IV Curve Tracer (Solar Cell)

In this lab, students construct and evaluate an automated current-voltage (I-V) curve tracer designed to characterize photovoltaic cells and solar panels. Using an Arduino Uno microcontroller mated to a custom high-power shield, students assemble an active electronic load driven by a SPI digital-to-analog converter (DAC) and high-current operational amplifiers capable of sinking up to 8 A. The system dynamically sweeps the terminal loading of a connected solar cell while measuring current across a low-resistance chassis-mounted shunt and reading scaled terminal voltages through analog-to-digital converter (ADC) channels. Through hardware assembly, sensor calibration, and experimental measurements, students explore operational amplifier power stages, automated data acquisition, thermal management, overcurrent relay protection, and the extraction of essential solar cell metrics including open-circuit voltage, short-circuit current, and maximum power point.

photovoltaics solar cell solar energy renewable energy IV curve tracer I-V characterization current-voltage curve operational amplifier op-amp power electronics Arduino Uno microcontroller digital-to-analog converter DAC analog-to-digital converter ADC SPI electronic load data acquisition maximum power point

Uploaded by demo on 2026-07-09 · ready · Electronics · Original source ↗

Files: directions.md · Parts List.xlsx · CircuitDesignV4.pdf · REVb.zip · IVCurve4_27.ino

Readiness checks

  • complete 2026-09-02 23:53 🛡 Cybersecurity: Review before networking · 1 finding 41 searches · 7 pages
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  • complete 2026-07-19 16:56 🛡 Cybersecurity: not checked 36 searches · 1 pages
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Latest report — 2026-09-02 23:53

Readiness: IV Curve Tracer (Solar Cell)

Verdict: At risk · 2026-09-02 · est. parts cost $200–$260 (PCB fabrication not priced) Cybersecurity — software & network: Review before networking

Every line of this lab's bill of materials can still be bought today, but the two OPA549S power op-amps — the most expensive parts on the board and, by the lab's own account, the ones with the least substitution latitude — have run dry since the last check. DigiKey, Mouser and Arrow all show zero stock with 26-week factory lead times, and a single authorized distributor holds 32 pieces. Order those now and the build proceeds; miss them and the lab waits about six months. That is the whole of the change: the verdict moves from Ready with caveats (2026-07-19) to At risk because of one part. Two problems the previous report raised have actually improved — the 20 kΩ resistor is stocked again, and the relay is not obsolete after all (that verdict rested on a different part number, corrected below).

Action required

Part Problem Recommended action
OPA549S New since the previous report. Zero stock at DigiKey, Mouser and Arrow; all three quote 26-week factory lead times. Only one authorized distributor holds stock (32 pieces). Order both units now from Spirit Electronics at $30.35. No substitute clears the board's 11-pin footprint — see Substitutes.
1461067-7 (relay K1) Changed since the previous report. The TE ordering number 1461067-7 has zero stock at every authorized distributor and a High lifecycle risk — but it is not obsolete: under its catalog name OJ-SS-124HM,000 the relay is Active. The previous report's "Obsolete" verdict came from a different relay (ORWH-SS-124D,N000). Order as OJ-SS-124HM,000 (10 in stock at Newark) or take the same-family OJE substitute with 5,309 in stock — see Substitutes.
HS50 R82 J Still zero stock at DigiKey (15-week lead time); unchanged since the previous report. Buy from Arrow, 200 in stock at $5.20. Mouser has 176 at $9.77 — 88% dearer for the same part.
FK20X7S1H106K Not For New Designs (unchanged). Lifecycle risk Med at ECIA. Buy the specified part while 140,934 pieces remain; only 1 per lab. The previous report's proposed replacement is also NFND — see Substitutes for the one Active option.
FK18X7R1H104K Not For New Designs (unchanged). Lifecycle risk Med at ECIA. Buy the specified part while 31,520 pieces remain; only 4 per lab. An Active drop-in on electricals is listed under Substitutes.
MF1/4DCT52R2002F Still zero stock at DigiKey (17-week lead), but easier than at the previous report, which found no stocked source at all. Buy from Mouser, 849 in stock at $0.12, or use the Yageo equivalent to keep a single DigiKey cart.

Cybersecurity — software & network

Review before networking — No firmware, library or toolchain version could be matched to any advisory or support database, and the documented setup requires running a Windows installer that is absent from the lab materials and would have to be re-obtained from the web — though the instrument itself has no network interface at all.

Component Version How known Support status
Solar Cell IV Curve Tracer firmware sketch (IVCurve4_27.ino) 4-27-16 inferred (date stamp in the sketch's own header comment as recorded in the lab snapshot; a revision date, not a package-registry version) —
Upstream base project — re-innovation PV_IV_Tracer (Arduino Code/PV_IV_Tracer_v7) not determined not determined (the repository was listed and its sketch and README fetched this run; the root and Arduino Code/ contain no manifest, lockfile or release metadata, so no version could be resolved) —
DAC_MCP49xx Arduino library not determined unpinned (the sketch includes <DAC_MCP49xx.h> with no version constraint; no manifest exists in the lab upload or in the upstream repository) —
Arduino SPI core library not determined not determined (bundled with whichever Arduino AVR core the builder installs; no version is recorded anywhere in the lab materials) —
Arduino IDE (build toolchain) not determined not determined (the lab documentation states no version; the stated download page https://www.arduino.cc/en/software returned an HTML page this run, and endoflife.date publishes no 'arduino' product, so no release cycle could be matched) —
IV Curve Tracer PC GUI (Installer.zip / VSProject.zip) not determined not determined (both archives are absent from the lab upload, so there is no binary or source to read a version from) —
Microsoft .NET Framework (host GUI runtime) not determined not determined (directions.md step 12 says only that the installer 'may require .NET framework'; no version is named and the host application is missing) —
Component Finding Severity Fix available?
IV Curve Tracer PC GUI (Installer.zip / VSProject.zip) The documented setup has the operator install and run a Windows executable (Installer.zip) that is missing from the lab materials, so it would have to be re-obtained from somewhere on the web and run on a lab PC without any way to check what it is. posture Mitigation only — drive the board with a short serial script written from the protocol documented in the sketch (115200 baud 8N1, handshake 'C'/'A', 'B' plus sweep parameters, data lines Vvoltage:04dcurrent:04d), or obtain Installer.zip only from the original project page and have it scanned before it runs on a lab machine.

What this means for your lab

This instrument has no network connection of any kind — no Ethernet, no Wi-Fi, no Bluetooth, no listening services and no passwords to change. The only link out of it is a USB cable to a single PC, so nobody else on your campus network can reach the instrument, read its measurements or drive the relay. The usual network precautions do not apply here. The one thing worth care is on the PC side: the lab's Windows program is missing from the uploaded materials, so whoever sets this up would have to download an executable from the internet and run it on a lab computer. Get it only from the original project's own page, have your IT group scan it first, or skip it entirely and talk to the board with a short serial script instead — the serial protocol is fully documented in the Arduino sketch. Everything else here could not be checked rather than checked clean: the sketch, the DAC library and the Arduino IDE carry no version numbers in the materials, the upstream project has no dependency file, and there is no vulnerability database that covers Arduino libraries or a hand-written sketch. Read 'nothing found' below as 'nothing was checkable', not as 'proven safe'.

Not checked

  • Solar Cell IV Curve Tracer firmware sketch (IVCurve4_27.ino): standalone Arduino sketch distributed with the lab; no package manager or registry, and no vulnerability database covers it
  • Upstream re-innovation PV_IV_Tracer repository: listed this run: neither the repository root nor Arduino Code/ contains a manifest or lockfile, so nothing could be resolved to a checkable version
  • DAC_MCP49xx Arduino library: unpinned — the sketch names the header with no version, no manifest exists, and no vulnerability database covers Arduino community libraries
  • Arduino SPI core library: bundled with whichever Arduino AVR core is installed; no version recorded and no vulnerability database covers Arduino core libraries
  • Arduino IDE (build toolchain): no version stated in the lab documentation, and endoflife.date publishes no 'arduino' product, so no support cycle could be matched
  • IV Curve Tracer PC GUI (Installer.zip / VSProject.zip): both archives are absent from the lab upload; there is no binary or source to inspect
  • Microsoft .NET Framework (host GUI runtime): version not stated in the lab documentation and the host application is missing, so nothing pins it
  • arduino not stated: support status: endoflife.date has no such product

Parts

Integrated circuits and active semiconductors

Part Spec/Package Status Stock Price Source Drift
OPA549S 8 A power op-amp, supply span 8–60 V / TO-220-11 Power Package Active, but single-sourced 0 at DigiKey (26-week lead); 32 at Spirit Electronics $30.35 Spirit Electronics (ECIA) Stock 188 → 0 at DigiKey; DigiKey list $34.44 unchanged
MCP4921-E/P 12-bit SPI DAC, 2.7–5.5 V / PDIP-8 Active 812 $2.81 DigiKey Stock 487 → 812; price flat
2N3904BU NPN switching transistor / TO-92 Active 166,982 $0.29 DigiKey $0.28 → $0.29; stock 231,511 → 166,982
1N4004 Rectifier diode, 400 V 1 A / DO-41 Active 199,396 $0.14 DigiKey Stock 178,689 → 199,396; price flat

Passive components: resistors

Part Spec/Package Status Stock Price Source Drift
HS50 R82 J 0.82 Ω, ±5%, 50 W, solder lugs / chassis mount, 49.10 × 14.20 mm Active 0 at DigiKey (15-week lead); 200 at Arrow, 176 at Mouser $5.20 Arrow (ECIA) Unchanged: Arrow 200 @ $5.20 then and now; Mouser 186 → 176
MF1/4DCT52R1001F 1 kΩ, 1%, 0.25 W / axial Active 72,713 $0.10 DigiKey Stock 79,993 → 72,713; price flat
MF1/4DCT52R3161F 3.16 kΩ, 1%, 0.25 W / axial Active 4,535 $0.10 DigiKey Stock 4,560 → 4,535; price flat
MF1/4DCT52R2002F 20 kΩ, 1%, 0.25 W / axial, 2.30 mm dia × 6.30 mm Active 0 at DigiKey (17-week lead); 849 at Mouser, 75,000 at TTI $0.12 Mouser (ECIA) Was "out of stock, no source"; now stocked at two distributors — improved
MF1/4DCT52R1003F 100 kΩ, 1%, 0.25 W / axial Active 1,849 $0.10 DigiKey Stock 9,933 → 1,849 (−81%); price flat
MF1/4DCT52R3163F 316 kΩ, 1%, 0.25 W / axial Active 4,873 $0.10 DigiKey Flat: 4,873 → 4,873, price unchanged
MF1/4DCT52R1002F 10 kΩ, 1%, 0.25 W / axial (BOM item 8) not checked — — — —

The 10 kΩ line is in the paper BOM only: the snapshot records that no 10 kΩ resistor appears in the EAGLE board or schematic, and it carries no sourcing plan, so no lookup was made.

Passive components: capacitors

Part Spec/Package Status Stock Price Source Drift
UPW1J101MPD 100 µF, ±20%, 63 V / radial can, 5.00 mm lead spacing, 10.00 mm dia Active 4,404 $0.74 DigiKey Stock 5,178 → 4,404; price flat
FK20X7S1H106K 10 µF, ±10%, 50 V, X7S / radial, 5.00 mm lead spacing (ordered as FK20X7S1H106KR000) Not For New Designs 140,934 $1.24 DigiKey Stock 141,750 → 140,934; price and status unchanged
FK18X7R1H104K 0.1 µF, ±10%, 50 V, X7R / radial, 2.50 mm lead spacing (ordered as FK18X7R1H104KN020) Not For New Designs 31,520 $0.28 DigiKey Stock 40,230 → 31,520 (−22%); price and status unchanged
FG18C0G1H100DNT06 10 pF, C0G, 50 V / radial, 2.5 mm lead pitch Active 4,432 $0.23 DigiKey Stock 4,525 → 4,432; price flat

One mechanical note on C1: the board footprint is a 7.5 mm can on 5.0 mm pitch and the lab's own substitution rule says "≤ 8 mm diameter", but DigiKey's parametrics put the specified UPW1J101MPD at 10.00 mm diameter. The lead spacing matches; the can is 2.5 mm wider than the footprint's nominal. Check clearance to the neighbouring parts, or pick a 100 µF / 63 V / 5 mm-pitch can of 8 mm or less.

Electromechanical, relays and power sources

Part Spec/Package Status Stock Price Source Drift
1461067-7 (OJ-SS-124HM,000) SPST-NO, 10 A contacts, 24 VDC coil (18.8 mA) / 5-pin through-hole PCB relay Active under the catalog number; the TE ordering number 1461067-7 has High lifecycle risk and no stock anywhere 0 at DigiKey; 10 at Newark $2.31 list · $2.55 in stock DigiKey / Newark (ECIA) Previously reported Obsolete, 0 stock — corrected: that verdict came from a different relay (ORWH-SS-124D,N000)
LRS-200-24 24 V DC, 8.8 A, 200 W / enclosed chassis PSU Active 777 $24.50 DigiKey Stock 945 → 777; price flat
OD9225-24HSS 24 V DC axial fan / 92 × 92 × 25 mm Active 119 $9.97 DigiKey Stock 161 → 119 (−26%); price flat

Microcontroller and interconnects

Part Spec/Package Status Stock Price Source Drift
A000073 (Arduino Uno Rev3) ATmega328P, 5 V logic / Uno R3 form factor Active 2,117 $26.30 DigiKey Same $26.30 as before, now from an authorized-distributor line rather than a shopping result
PRT-00553 (0.1" breakaway male header, 40-pin) 2.54 mm pitch single-row male header strip Active as a generic part; the SparkFun part number itself was not priced this run Retail stock $0.95 Jameco Previously $0.30 for PRT-00553 at SparkFun; that listing did not return this run
RA-T2X-64E Extruded heatsink, ~4.8 °C/W, solder tabs / TO-220 vertical Active 1,147 $6.05 DigiKey Stock 1,338 → 1,147; price flat
1581-0 Black 4 mm banana jack / panel mount Active 16,911 $3.19 DigiKey $3.10 → $3.19 (+2.9%); stock 18,687 → 16,911
1581-2 Red 4 mm banana jack / panel mount Active 10,719 at DigiKey (7 distributors stocked) $3.19 DigiKey (via ECIA) $3.10 → $3.19 (+2.9%); stock 8,740 → 10,719
Wire terminals / test points (24V, GND, SC+, SC−) Board wirepads and test pads Not an orderable part — fabricated with the PCB — — — —

DigiKey's keyword search does not surface the Pomona part for the string "1581-2" — it returns a ferrite bead, a jumper, a header and an LED, none of which is this part. The stock and price above come from the authorized-distributor corroboration, which does return Pomona 1581-2.

Mechanical enclosure and assembly hardware

Part Spec/Package Status Stock Price Source Drift
Project enclosure box (Hefty 7099HFT-010-111-044, 6.5 qt) Clear polypropylene box, needs ≥ 12" × 8" × 4.5" inside Exact model not found; equivalents available Retail stock $1.25 Target (Brightroom 6 qt clear box) Previously $5.97 at Walmart; that listing did not return this run
PG9 waterproof cable gland PG9 thread, 4–8 mm cable Readily available Retail stock $0.20 Pixel Paradise USA Unchanged at $0.20, same seller
M3 nylon standoff / screw kit M3 nylon male-female standoffs and screws Readily available Retail stock $3.75 SpeedyFPV (180-piece kit) Previously bundled with M4 hardware at ~$15.00; itemised here
Chassis nylon spacers (Hillman 880444) 5/8" OD × 1/4" ID × 3/8" long nylon Readily available, exact dimensions matched Retail stock $2.97 Home Depot (Everbilt) —
M4-0.70 × 25 mm screws, lock nuts, washers M4 metric hardware Readily available Retail stock $11.07 Harfington (100 pcs with hex locknuts) Previously bundled with M3 hardware at ~$15.00; itemised here
Arctic Silver 5 thermal compound 3.5 g syringe, electrically non-conductive Readily available Retail stock $9.69 Quiet PC —
14 AWG stranded hookup wire (red, black) 14 AWG stranded copper, ≥ 10 A Readily available Retail stock $14.95 ZYLtech (5 m red + 5 m black) —
3-conductor grounded AC power cord NEMA 5-15P to bare pigtail leads, 120 V 10 A Readily available Retail stock $12.99 eBay (bare-lead appliance cord) —
4 mm banana test leads (red, black pair) Shrouded/stackable, needs ≥ 10 A DC Readily available; current rating not stated by any seller Retail stock $18.29 eBay (Goupchn silicone shrouded set) —

The enclosure and the test leads are the two retail lines whose deciding claim could not be confirmed: no listing states the box's internal dimensions, and none states the leads' current rating. Both are recorded as plausible but unverified — measure the box before drilling, and check the leads' rating before running the lab's 8 A test current through them.

Substitutes

For part Substitute Differences Verified Judgment
OPA549S OPA549T Identical electricals — 10 A output, 8–60 V supply span, 900 kHz gain-bandwidth — so the +24 V rail is covered. Package differs: "TO-220-11 Formed Leads" against the OPA549S's "TO-220-11, Power Package". Separately it has zero stock at every authorized distributor surveyed (Spirit 0, Arrow 0 at 26 weeks, DigiKey 0 at 26 weeks, Mouser 0 with 2,501 on order) and a High supply-chain risk. verified: supply-voltage range 8–60 V against the lab's +24 V rail, output current 10 A, and both parts' package strings (DigiKey parametrics). not verified: that the OPA549T lead pattern mates with the board's 11-pin staggered footprint. Not acceptable — the footprint is unverified and it is unobtainable anyway. No other part in the evidence combines 8 A continuous output with the 11-lead TO-220 footprint, and DigiKey lists no substitutes for the OPA549S.
1461067-7 (OJ-SS-124HM,000) OJE-SS-124HM,000 — Active, 5,309 in stock, $2.33 Same TE OJ/OJE family the lab specifies and the same catalogue description, "RELAY GEN PURPOSE SPST 10A 24V": SPST-NO contact form, 10 A contact rating and 24 VDC coil all match. DigiKey classifies it a "Parametric Equivalent" of the specified relay. Costs $0.02 more and, unlike the specified part, is in stock in quantity. verified: contact form (SPST, 1 Form A), 10 A contact rating, 24 VDC coil, and DigiKey's parametric-equivalent classification. not verified: the 5-pin footprint and pin layout — DigiKey's relay parametrics do not publish pin spacing. Acceptable on electricals, footprint not verified. Check the OJE pinout drawing against the board's five 1.32 mm holes before ordering in quantity.
1461067-7 (OJ-SS-124HM,000) G5LE-14 DC24 — Active, 19,237 in stock, $1.73 The substitute the previous report proposed. It comes from a different relay family than the OJ/OJE series the lab requires. Cheapest of the three options. not stated beyond Active status, price and stock: this lookup was pre-screened as routine and returned no parametrics, so contact form, contact rating and coil voltage could not be re-confirmed this run, and the footprint remains unverified exactly as the previous report left it. Not verified. Prefer the OJE-SS-124HM,000 — same family, only $0.60 dearer.
MF1/4DCT52R2002F MFR-25FBF52-20K — Active, 58,021 in stock, $0.11 Resistance, tolerance, power rating and temperature coefficient are identical (20 kΩ, ±1%, 0.25 W, ±100 ppm/°C); axial in both cases; body 2.40 mm × 6.30 mm against 2.30 mm × 6.30 mm — 0.1 mm fatter, same length. Same nominal value, so the firmware's ADC scaling constants are untouched. Watch the suffix: DigiKey's top hit for this search is MFR-25FBF52-20K5, which is 20.5 kΩ, not 20 kΩ. verified: resistance, tolerance, power rating, temperature coefficient, axial package and body dimensions, from DigiKey parametrics for both parts. Lead pitch on an axial resistor is set at assembly, so the board's 10 mm pitch needs no separate check. Acceptable — exact functional equivalent.
FK20X7S1H106K FG20X7R1H106KRT00 — Active, 915 in stock, $1.41 10 µF, 50 V, radial, with an X7R dielectric instead of X7S — explicitly inside the lab's stated latitude of X5R/X7R/X7S. DigiKey classifies it a "Direct" substitute for the specified part. The only Active option found; $0.17 dearer. verified: capacitance, 50 V rating and X7R dielectric (DigiKey substitute record and product description), and that the lab permits X7R. not verified: lead spacing and body size — this lookup was pre-screened as routine and returned no parametrics. Acceptable on electricals, footprint not verified. Measure the lead pitch against the 2.5/5.0 mm pads before committing.
FK20X7S1H106K FG20X7S1H106KRT06 — 9,556 in stock, $1.36 The substitute the previous report recommended. Dimensionally identical to the original — 10 µF, ±10%, 50 V, X7S, 5.50 × 4.00 mm, 7.00 mm tall, 5.00 mm lead spacing — but it is also Not For New Designs, and costs 10% more. verified: capacitance, tolerance, voltage rating, dielectric, body size and lead spacing (5.00 mm), from DigiKey parametrics for both parts. A true drop-in, but not an upgrade — it carries the same Not For New Designs status as the part it would replace, which the previous report did not record.
FK18X7R1H104K K104K15X7RF5TL2 — Active, 218,939 in stock, $0.29 0.1 µF, 50 V, X7R, radial — matches the requirement of 100 nF, ≥ 50 V radial ceramic exactly on electricals. DigiKey classifies it a "Direct" substitute. $0.01 dearer, with seven times the stock. verified: capacitance, voltage rating, dielectric and radial construction (DigiKey substitute record and product description) plus DigiKey's own "Direct" classification. not verified: lead spacing and body size — this lookup was pre-screened as routine and returned no parametrics, so the 2.5 mm pitch the previous report claimed cannot be reproduced from this run's evidence. Electrically equivalent, footprint not verified. A same-family alternative, TDK FG18X7R1H104KNT00 ("Direct", $0.23, 6,808 in stock), is cheaper but equally unverified on footprint.

Verify any substitute against its own datasheet before ordering — particularly the footprint and lead pitch, which this check could not confirm for the relay or for either ceramic capacitor.

Other dependencies

  • PCB fabrication — the package is complete and ready to quote as-is: 2 copper layers, 100.00 mm × 80.00 mm, RS-274X Gerbers (top and bottom copper, both solder masks, top silkscreen, mechanical outline) plus Excellon drill data, 142 plated through-holes across 13 tool diameters, generated with the SparkFun 2-layer CAM script. Not priced this run — no fabrication quote was in the sourcing plan. Correction: the previous report gave the board as "approx. 69 mm × 53 mm"; the mechanical outline Gerber gives 100 × 80 mm.
  • Advanced Circuits (4pcb.com), the fabricator the lab names — a fetch was attempted this run and the page returned no readable text, so the fabricator's current status is not checked. Any 2-layer prototype house can take this package.
  • Instructables project page (https://www.instructables.com/IV-Curve-Tracer/) — a fetch was attempted this run; the page downloaded but no readable text could be extracted, so its contents are not checked. The previous report stated that the lab's missing archives are "likely available on the project's Instructables page"; nothing gathered this run confirms that, and it should not be relied on until someone opens the page by hand.
  • Open-source base repository link (github.com/re-innovation/PV_IV_Tracer) — the link is live: a directory listing returned five entries on branch master this run.
  • Missing curriculum documents — Capstone Lesson Presentation.pdf and Solar Powered Energy Demo.docx are referenced by the lab but absent from the upload, and no URL is given for either. Not checked — there is nothing to fetch.

Watch list

  • OPA549S — the whole verdict rests on this part. Two are needed, 32 exist at one authorized distributor, and everyone else quotes 26 weeks. If those 32 go before the next check, this lab becomes unbuildable for roughly half a year, and there is no footprint-compatible alternative.
  • MF1/4DCT52R1003F (100 kΩ) — fell from 9,933 to 1,849 pieces in seven weeks, the fastest decline of any passive here. Only 2 are needed and 1% metal-film 100 kΩ resistors are a commodity, but it is the line to watch.
  • Both TDK ceramics (FK20X7S1H106K, FK18X7R1H104K) — Not For New Designs, ECIA lifecycle risk Med, and only one stocked authorized distributor each beyond DigiKey. Today's stock is deep enough that this is a two-or-three-year problem rather than a next-check problem, but the escape routes are unverified on footprint.
  • The relay's footprint — the OJE-SS-124HM,000 is the practical way to get this relay in quantity, and the one thing nobody has checked is whether its pins land in the board's five 1.32 mm holes. Confirm that once, from the datasheet, and the risk disappears permanently.
  • OD9225-24HSS (fan) — down 26% to 119 pieces. Low consequence: any 92 × 92 × 25 mm 24 V axial fan does the job.
Snapshot What the lab depended on when it was uploaded — the baseline the readiness checks research against.

Overview and System Architecture

This lab constructs an automated Solar Cell I-V (Current vs. Voltage) Curve Tracer designed as an Electrical and Computer Engineering capstone project at The Ohio State University. The hardware consists of a custom two-layer PCB shield mated to an Arduino Uno microcontroller development board. The system utilizes a Microchip MCP4921 12-bit SPI digital-to-analog converter (DAC) driving two Texas Instruments OPA549 high-current operational amplifiers configured to sweep terminal loading across a solar cell under test while measuring current and voltage via resistive voltage dividers into the Arduino analog-to-digital converter (ADC) inputs. A 24 V electromechanical relay disconnects the device under test when idle or during overcurrent fault conditions (cutoff threshold set at 8.0 A). The system operates across two main electrical domains: a 5 V DC logic rail powered by the Arduino Uno board (supplying the DAC VDD and VREF), and a high-power 24 V DC rail (Mean Well 200 W power supply) energizing the OPA549 op-amp power stages, the relay coil, and the 24 V chassis cooling fan. The operational amplifiers run in a single-supply configuration with a 12 V mid-supply reference generated by a 1 kΩ / 1 kΩ resistive divider.

Bill of Materials

Integrated Circuits and Active Semiconductors

  • High-Current Power Operational Amplifiers (U1, U2 on PCB; U2, U3 in schematic)

    • Identity: Texas Instruments OPA549S
    • Quantity: 2
    • Footprint / Package: 11TO-220 (11-pin staggered through-hole SIP/ZIP, TI package KV-11 / DDPAK-style vertical power package with tab)
    • Electrical Constraints: Operating on +24 V DC single supply (VS+ = +24 V, VS- = GND). Must support continuous output currents up to 8 A (OPA549 rated to 8 A continuous, 10 A peak) and supply voltage range encompassing 24 V (rated 8 V to 60 V). Pin 8 (ILIM) is tied to GND for maximum internal current limit.
    • Substitution Latitude: Extremely low substitution latitude. The circuit topology, thermal layout, and compensation rely on the specific drive capability, thermal shutdown behavior, and 11-lead staggered pinout of the OPA549S. Any replacement must be an 8 A to 10 A continuous output power op-amp capable of 24 V to 30 V single-supply operation and compatible with the 11-pin TO-220 footprint and board-mounted heatsinks.
    • User Control: No (automated operational amplifier stage).
    • Sourcing Plan: distributor lookup: OPA549S

  • 12-Bit Digital-to-Analog Converter (U3 on PCB; U2 / MCP4921-E/P in schematic)

    • Identity: Microchip Technology MCP4921-E/P
    • Quantity: 1
    • Footprint / Package: DIL08 (8-pin Plastic Dual In-Line Package, PDIP-8, 300 mil row spacing)
    • Electrical Constraints: VDD and VREF tied to Arduino +5 V rail. Communicates via SPI (CS on digital pin 10, SCK on digital pin 13, SDI on digital pin 11). LDAC (pin 5) is tied directly to GND on the PCB for unbuffered immediate DAC updates. Supply voltage range 2.7 V to 5.5 V.
    • Substitution Latitude: Low substitution latitude. Must be register- and command-compatible with the MCP4921 SPI protocol as implemented in the firmware library, and must be in a DIP-8 package with matching pinout.
    • User Control: No.
    • Sourcing Plan: distributor lookup: MCP4921-E/P

  • NPN Switching Bipolar Junction Transistor (T1 on PCB; Q1 in schematic)

    • Identity: onsemi / Fairchild Semiconductor 2N3904BU
    • Quantity: 1
    • Footprint / Package: TO-92 (through-hole, straight leads)
    • Electrical Constraints: Low-side relay coil driver. Collector tied to relay coil and +24 V rail (via coil), emitter tied to ground, base driven from Arduino D4 via a 20 kΩ / 100 kΩ divider network. VCEO ≥ 40 V, IC ≥ 100 mA (relay coil draws ~15 mA at 24 V).
    • Substitution Latitude: High substitution latitude. Any general-purpose NPN silicon transistor in a TO-92 package with VCEO ≥ 40 V, IC ≥ 100 mA, and matching pinout (E-B-C or bent to fit 1-Collector, 2-Base, 3-Emitter) is suitable.
    • User Control: No.
    • Sourcing Plan: distributor lookup: 2N3904BU

  • Flyback / Freewheeling Suppression Diode (D1)

    • Identity: Fairchild Semiconductor 1N4148 in BOM and schematic; 1N4004 on PCB element list.
    • Quantity: 1
    • Footprint / Package: DO41-10 (standard DO-41 axial diode package with 10 mm lead pitch on PCB; DO-35 axial package specified by 1N4148 BOM entry).
    • Electrical Constraints: Sits across 24 V relay coil (cathode to +24 V, anode to collector of T1). Must withstand reverse breakdown voltage VR ≥ 40 V and peak repetitive reverse current ≥ 50 mA.
    • Reconciliation / Discrepancy Note: The BOM and schematic specify a 1N4148 high-speed switching diode (DO-35 package), but the PCB board layout (REVB.brd) specifies a 1N4004 power rectifier (DO-41 package, 400 V, 1 A). Because the PCB hole spacing is 10 mm (DO-41), a standard 1N4004 (or 1N4007) fits mechanically without bending leads inward, though an axial 1N4148 can be mounted by bending leads to fit the 10 mm pitch. Prefer a 1N4004 / 1N4007 per the board file.
    • Substitution Latitude: High substitution latitude. Any silicon rectifier or fast recovery diode rated for VRRM ≥ 50 V and IF ≥ 200 mA in an axial DO-41 or DO-35 package works.
    • User Control: No.
    • Sourcing Plan: distributor lookup: 1N4004

Passive Components: Resistors

  • Chassis-Mount Aluminum-Housed Current Sense Resistor (R6)

    • Identity: ARCOL / Ohmite HS50 R82 J (HS50 series)
    • Quantity: 1
    • Footprint / Package: HS50 (aluminum-housed chassis mount power resistor with solder lugs, mounted mechanically to power supply mesh cover with 0.82 Ω value label)
    • Electrical Constraints: Resistance: 0.82 Ω, tolerance ±5%, power rating: 50 W. Carries full solar cell test current up to 8 A. At 8 A, instantaneous dissipation is P = I^2 * R = 64 * 0.82 = 52.5 W (intermittent during curve sweep).
    • Substitution Latitude: Low substitution latitude. Must be a 0.82 Ω resistor with a minimum continuous power rating of 50 W (when heatsinked) and low inductance/temperature coefficient. Changing the resistance value requires modifying the firmware calibration constant in the current calculation formula.
    • User Control: No.
    • Sourcing Plan: distributor lookup: HS50 R82 J

  • Precision 1/4 W Metal Film Resistors (1% Tolerance, Axial 0207/10 Footprint)

    • Identity: KOA Speer MF1/4DCT52R series (axial through-hole metal film resistors, 1/4 W, 1% tolerance, footprint 0207/10 with 10 mm lead pitch):
      • 1 kΩ 1% (MF1/4DCT52R1001F): Quantity 4 (R1, R2, R4, R9). R1 and R2 form the +12 V mid-rail bias divider from the +24 V bus. R4 forms the ground leg of the positive voltage sense divider (with R3). R9 forms the ground leg of the current sense ADC divider (with R5).
      • 3.16 kΩ 1% (MF1/4DCT52R3161F): Quantity 2 (R3, R5). R3 is the op-amp U1 feedback / scaling resistor. R5 is the high-side scaling resistor for the current sense ADC input.
      • 20 kΩ 1% (MF1/4DCT52R2002F): Quantity 1 (R12). Base drive current-limiting resistor from Arduino D4 to T1 base.
      • 100 kΩ 1% (MF1/4DCT52R1003F): Quantity 2 (R11, R13). R11 forms the lower leg of the negative terminal voltage sense divider. R13 forms the base pulldown resistor on T1.
      • 316 kΩ 1% (MF1/4DCT52R3163F): Quantity 1 (R10). Upper leg of the negative terminal voltage sense divider (attenuation ratio 100 kΩ / (316 kΩ + 100 kΩ) = 1/4.16).
      • Note on Unused BOM Item: BOM item 8 lists 10 kΩ 1% resistors (MF1/4DCT52R1002F, quantity 5), but no 10 kΩ resistor exists in the EAGLE board design or schematic.
    • Electrical Constraints: Maximum operating voltage 250 V, power rating 0.25 W, tolerance ±1%.
    • Substitution Latitude: High substitution latitude for identical resistance and tolerance. Any standard 1/4 W metal film axial resistor with 1% tolerance and matching lead pitch is an exact functional substitute. Divider ratios (3.16 kΩ / 1 kΩ and 316 kΩ / 100 kΩ) are critical to firmware ADC voltage scaling constants (4.14x to 4.16x attenuation).
    • User Control: No.
    • Sourcing Plan: distributor lookup (representative example — sources give spec only): KOA Speer MF1/4DCT52R series:
      • 1 kΩ: MF1/4DCT52R1001F
      • 3.16 kΩ: MF1/4DCT52R3161F
      • 20 kΩ: MF1/4DCT52R2002F
      • 100 kΩ: MF1/4DCT52R1003F
      • 316 kΩ: MF1/4DCT52R3163F

Passive Components: Capacitors

  • Power Bus Bulk Radial Electrolytic Capacitor (C1)

    • Identity: Nichicon UPW1J101MPD (UPW series low impedance). Note: BOM line 15 lists part number FK20X7S1H106K erroneously copied from line 13, but the description specifies "100uF Electrolytic Capacitor" and links directly to Nichicon UPW1J101MPD.
    • Quantity: 1
    • Footprint / Package: C050-050X075 (radial can, 5.0 mm lead spacing, 7.5 mm can diameter)
    • Electrical Constraints: Capacitance: 100 µF, voltage rating: 63 V DC (sitting directly across the +24 V DC bus to ground).
    • Substitution Latitude: High substitution latitude. Any aluminum electrolytic capacitor of 100 µF rated at ≥ 35 V (preferably 50 V or 63 V) with 5 mm lead spacing and ≤ 8 mm diameter.
    • User Control: No.
    • Sourcing Plan: distributor lookup: UPW1J101MPD

  • DC Bus Ceramic Filter Capacitor (C2)

    • Identity: TDK FK20X7S1H106K (FK20 series)
    • Quantity: 1
    • Footprint / Package: C025-024X044 (radial leaded ceramic, 2.5 mm / 0.1 inch lead pitch)
    • Electrical Constraints: Capacitance: 10 µF, voltage rating: 50 V DC (sits across +24 V rail to ground).
    • Substitution Latitude: High substitution latitude. Any 10 µF, ≥ 35 V, X5R/X7R/X7S radial ceramic capacitor with 2.5 mm or 5.0 mm lead spacing.
    • User Control: No.
    • Sourcing Plan: distributor lookup: FK20X7S1H106K

  • Bypass and Decoupling Ceramic Capacitors (C3, C4, C5, C8)

    • Identity: TDK FK18X7R1H104K (FK18 series)
    • Quantity: 4 on board (BOM specifies quantity 10)
    • Footprint / Package: C025-024X044 (radial leaded ceramic, 2.5 mm / 0.1 inch lead pitch)
    • Electrical Constraints: Capacitance: 100 nF (0.1 µF), dielectric X7R, voltage rating: 50 V DC. C3 and C4 sit on the +24 V bus near the op-amps; C5 filters the DAC output; C8 decouples the DAC +5 V supply (VDD).
    • Substitution Latitude: High substitution latitude. Any standard 100 nF, ≥ 50 V radial ceramic capacitor with 2.5 mm lead spacing.
    • User Control: No.
    • Sourcing Plan: distributor lookup: FK18X7R1H104K

  • Feedback and Noise Filter Ceramic Capacitors (C6, C7)

    • Identity: TDK FG18C0G1H100DNT06 (FG18 series)
    • Quantity: 2 on board (C6 across Voltage Sense 2 divider; C7 across U1 feedback divider. Schematic PDF only draws C6; board places both C6 and C7). BOM specifies quantity 5.
    • Footprint / Package: C025-024X044 (radial leaded ceramic, 2.5 mm / 0.1 inch lead pitch)
    • Electrical Constraints: Capacitance: 10 pF, dielectric C0G (NP0), voltage rating: 50 V DC, tolerance ±0.5 pF.
    • Substitution Latitude: High substitution latitude. Any 10 pF, ≥ 50 V C0G/NP0 ceramic capacitor with 2.5 mm lead spacing.
    • User Control: No.
    • Sourcing Plan: distributor lookup: FG18C0G1H100DNT06

Electromechanical, Relays, and Power Sources

  • High-Current SPST-NO / SPDT Power Relay (K1)

    • Identity: TE Connectivity / Potter & Brumfield / OEG 1461067-7 (OJ-SS-124HM,000)
    • Quantity: 1
    • Footprint / Package: TE OJ-SS series relay footprint (5-pin through-hole, sealed miniature PCB relay, 18.2 mm × 10.2 mm × 15.0 mm)
    • Electrical Constraints: Coil voltage: 24 V DC (nominal coil resistance ~1.6 kΩ, coil power ~360 mW). Contact rating: 10 A at 250 V AC / 30 V DC (form A, normally open). Switched in series with the solar cell return path.
    • Substitution Latitude: Low to moderate substitution latitude. Must match the exact 5-pin PCB footprint and pinout of the TE OJ-SH/OJ-SS series relay, have a 24 V DC coil, and possess contacts rated for at least 10 A DC switching.
    • User Control: No (actuated by firmware protection and sequence logic).
    • Sourcing Plan: distributor lookup: 1461067-7

  • Main System Power Supply Unit (PSU)

    • Identity: Mean Well LRS-200-24
    • Quantity: 1
    • Footprint / Package: Enclosed metal chassis switching power supply with perforated honeycomb cover and screw terminals (215 mm × 115 mm × 30 mm).
    • Electrical Constraints: Input: 115 V / 230 V AC selectable. Output: 24 V DC, 8.8 A (200 W continuous). Powers the shield op-amps, cooling fan, and relay coil.
    • Substitution Latitude: Moderate substitution latitude. Any industrial enclosed 24 V DC switching power supply delivering ≥ 8.5 A (≥ 200 W) with terminal block connections can substitute electrically, though mounting screw patterns on the enclosure base and cover standoff spacing may vary.
    • User Control: AC input voltage selector switch (set-once prior to power-on; not a student lab control).
    • Sourcing Plan: distributor lookup: LRS-200-24

  • Chassis Exhaust / Enclosure Cooling Fan

    • Identity: Orion Fans OD9225-24HSS
    • Quantity: 1
    • Footprint / Package: 92 mm × 92 mm × 25 mm square axial DC brushless fan
    • Electrical Constraints: Operating voltage: 24 V DC (wired directly to PSU 24 V output terminals). High speed / sleeve bearing (approx. 52 CFM airflow).
    • Substitution Latitude: High substitution latitude. Any standard 92 mm × 92 mm × 25 mm 24 V DC axial brushless cooling fan with two wire leads.
    • User Control: No.
    • Sourcing Plan: distributor lookup: OD9225-24HSS

Microcontroller and Interconnects

  • Microcontroller Host Board

    • Identity: Arduino Uno Rev3 (Arduino part number A000073)
    • Quantity: 1
    • Footprint / Package: Standard Arduino Uno form factor (DIP ATmega328P, USB Type-B connector, 8-pin and 6-pin female header sockets).
    • Electrical Constraints: 5 V logic rail (ATmega328P @ 16 MHz), powered via USB connection to PC host. Provides +5 V VDD and reference to DAC U3 and ADC reference voltage.
    • Substitution Latitude: Low substitution latitude. Requires exact physical alignment of shield male headers to Arduino Uno R3 header geometry and identical ATmega328P hardware timers / SPI peripheral pinout.
    • User Control: Reset push-button (set-once / board reset).
    • Sourcing Plan: distributor lookup: A000073

  • Shield Header Pins

    • Identity: SparkFun PRT-00553 (0.1" breakaway male header strip, 40-pin)
    • Quantity: 1 strip (cut to length: 1x 10-pin, 2x 8-pin, 1x 6-pin)
    • Footprint / Package: 0.1 inch (2.54 mm) pin pitch through-hole male headers
    • Electrical Constraints: Rated ≥ 1 A per pin.
    • Substitution Latitude: High substitution latitude. Any standard 0.1" pitch single-row breakaway male pin headers.
    • User Control: No.
    • Sourcing Plan: retail shopping search: 0.1 inch breakaway male pin headers 40 pin

  • Heatsinks for OPA549S Op-Amps (U$7, U$8)

    • Identity: Ohmite RA-T2X-64E
    • Quantity: 2
    • Footprint / Package: Extruded aluminum heatsink with solderable retaining tabs / solder pins designed for TO-220 / vertical SIP packages (PCB footprint DanECE4901:RA-T2X-64E).
    • Electrical Constraints: Thermal resistance ~4.8 °C/W. Must accommodate the 11-lead TO-220 package and solder tab pins into PCB isolated copper holes ISO1 and ISO2.
    • Substitution Latitude: Low substitution latitude without board re-drilling. The PCB has dedicated plated mounting holes matching the specific solderable pins of the RA-T2X-64E extrusion.
    • User Control: No.
    • Sourcing Plan: distributor lookup: RA-T2X-64E

  • Front Panel Banana Test Jacks

    • Identity:
      • Black Banana Jack (Negative Test Terminal): Pomona Electronics 1581-0
      • Red Banana Jack (Positive Test Terminal): Pomona Electronics 1581-2
    • Quantity: 1 Black (1581-0), 1 Red (1581-2)
    • Footprint / Package: Panel mount uninsulated / insulated binding jack for 4 mm banana plugs, mounting in 0.25" chassis hole.
    • Electrical Constraints: Current rating ≥ 10 A DC, voltage rating ≥ 30 V DC.
    • Substitution Latitude: High substitution latitude. Any standard chassis-mount 4 mm banana jacks rated for ≥ 10 A.
    • User Control: Yes, student-operated connection interface (banana test lead plugging).
    • Sourcing Plan:
      • Black jack: distributor lookup: 1581-0
      • Red jack: distributor lookup: 1581-2

  • PCB Wire Terminals / Test Points (24V, GND, SC+, SC-)

    • Identity: Through-hole wire pads on PCB:
      • 24V: wirepad 4,16O1,6 (large diameter plated hole for 14 AWG power wire from PSU V+)
      • GND: wirepad 4,16O1,6 (large diameter plated hole for 14 AWG power wire from PSU V-)
      • SC+: testpad TPSPAD1-20 (plated pad for wire to red banana jack)
      • SC-: testpad TPSPAD1-20 (plated pad for wire to black banana jack)
    • Quantity: 4 connection points
    • Footprint / Package: Board wirepads / test pads
    • Substitution Latitude: Soldered directly with hookup wire.
    • User Control: No.
    • Sourcing Plan: Not an independent part; fabricated as part of PCB.

Mechanical Enclosure and Assembly Hardware

  • Project Enclosure Box

    • Identity: Hefty Clear Storage Box 6.5 Quart (Hefty model 7099HFT-010-111-044)
    • Quantity: 1
    • Footprint / Package: Clear polypropylene plastic storage shoe box container (approx. 13.7" L × 8.1" W × 4.6" H).
    • Electrical / Mechanical Constraints: Houses the Mean Well power supply, Arduino Uno, shield PCB, and cooling fan. Must allow drilling for fan intake/exhaust, AC power gland, USB port access, and banana jacks.
    • Substitution Latitude: High substitution latitude. Any non-conductive plastic storage box or electronics enclosure with internal dimensions of at least 12" × 8" × 4.5" is suitable.
    • User Control: Removable lid for inspection.
    • Sourcing Plan: retail shopping search: Hefty clear storage box 6.5 qt

  • AC Power Entry Cable Gland

    • Identity: PG9 Waterproof Plastic Cable Gland
    • Quantity: 1 (or pack of 10)
    • Footprint / Package: PG9 thread (15.2 mm mounting hole), accommodates cable diameter 4 mm to 8 mm.
    • Electrical Constraints: Strain relief and abrasion protection for line-voltage AC power cord passing through enclosure wall.
    • Substitution Latitude: High substitution latitude. Any standard PG9, PG11, or M16 cable gland.
    • User Control: No.
    • Sourcing Plan: retail shopping search: PG9 cable gland waterproof

  • M3 PCB Standoffs / Spacers Kit

    • Identity: Teenitor M3 Nylon Male-Female Standoffs / Screws Assortment Kit
    • Quantity: 1 kit (requires 4 M3 nylon standoffs and screws)
    • Footprint / Package: M3 thread nylon standoffs (5 mm to 10 mm length) and M3 nylon screws.
    • Electrical Constraints: Non-conductive isolation between the Arduino Uno / shield and the metal honeycomb cover of the Mean Well PSU.
    • Substitution Latitude: High substitution latitude. Any M3 non-conductive (nylon) male-female standoffs and screws.
    • User Control: No.
    • Sourcing Plan: retail shopping search: M3 nylon standoff kit

  • Chassis Standoff Spacers

    • Identity: Hillman / Lowe's Item 880444 (Nylon Spacer 5/8" OD × 1/4" ID × 3/8" Length)
    • Quantity: 4 (used in step 7 to stand the PSU off the plastic box floor)
    • Footprint / Package: 5/8" outer diameter, 1/4" inner diameter, 3/8" length cylindrical nylon spacer.
    • Substitution Latitude: High substitution latitude. Any non-conductive cylindrical spacer with 1/4" or M4 through-hole and 3/8" (approx. 10 mm) height.
    • User Control: No.
    • Sourcing Plan: retail shopping search: 5/8 x 1/4 x 3/8 nylon spacer

  • Chassis Assembly Screws, Nuts, and Washers

    • Identity:
      • M4-0.70 × 25 mm Pan Head Machine Screws (Lowe's Item 127096): Quantity 4 (mounts PSU through enclosure base)
      • M4-0.70 Lock Nuts with Nylon Inserts (Lowe's Item 127092): Quantity 4
      • 4 mm Flat Washers (Lowe's Item 127072): Quantity 8 (used under screw heads and on PSU honeycomb cover)
    • Footprint / Package: M4 metric standard hardware
    • Substitution Latitude: High substitution latitude. Standard zinc-plated or stainless steel M4 hardware.
    • User Control: No.
    • Sourcing Plan: retail shopping search: M4-0.70 x 25mm machine screws lock nuts washers

  • Thermal Interface Material

    • Identity: Arctic Silver 5 Polysynthetic Thermal Compound (3.5 g tube)
    • Quantity: 1 tube
    • Footprint / Package: Syringe dispenser
    • Constraints: Electrically non-conductive, high thermal conductivity (applied between OPA549S tabs and RA-T2X-64E heatsinks, and between R6 base and PSU metal cover).
    • Substitution Latitude: High substitution latitude. Any quality non-conductive zinc-oxide, polysynthetic, or silicone thermal grease.
    • User Control: No.
    • Sourcing Plan: retail shopping search: Arctic Silver 5 thermal compound

  • High-Current Internal Hookup Wire

    • Identity: Southwire / Southwest Wire 55669121 (14 AWG Stranded Copper Hookup Wire, 20 ft)
    • Quantity: ~3 ft needed (cut to length)
    • Footprint / Package: 14 AWG stranded PVC-insulated hookup wire (black, red)
    • Electrical Constraints: Must safely carry up to 8.8 A continuous DC current from PSU to PCB wirepads and from PCB output pads to front panel banana jacks.
    • Substitution Latitude: High substitution latitude. Any 14 AWG or 16 AWG stranded copper insulated wire rated for ≥ 10 A.
    • User Control: No.
    • Sourcing Plan: retail shopping search: 14 AWG stranded hookup wire red black

  • AC Line Power Cord

    • Identity: 3-Conductor Grounded AC Power Cord (NEMA 5-15P to bare pigtail leads)
    • Quantity: 1
    • Footprint / Package: 18/3 or 16/3 SJT power cable with grounded North American plug
    • Electrical Constraints: 120 V AC, 10 A rated, carrying AC Line, Neutral, and Earth Ground to Mean Well PSU terminal strip.
    • Substitution Latitude: High substitution latitude. Standard commercial AC replacement power cord.
    • User Control: Main plug disconnect.
    • Sourcing Plan: retail shopping search: 3 prong grounded AC power cord bare leads

  • Banana Plug Test Leads

    • Identity: 4 mm Shrouded / Stackable Banana-to-Banana or Banana-to-Alligator Test Leads
    • Quantity: 1 pair (red, black)
    • Constraints: Rated ≥ 10 A DC, connecting solar panel terminals to red/black front panel banana jacks.
    • Substitution Latitude: High substitution latitude.
    • User Control: Yes, handled by students to hook up solar panels.
    • Sourcing Plan: retail shopping search: 4mm banana jack test leads heavy duty

Software and Network Dependencies

Microcontroller Firmware and Embedded Dependencies

  • Firmware Program

    • Name: Solar Cell IV Curve Tracer Sketch (IVCurve4_27.ino)
    • Source: Provided in lab upload. Derived from Matt Little / OpenEnergyMonitor PV IV Tracer project (re-innovation GitHub repository).
    • Version: Stated in code comments as 4-27-16 (dated April 27, 2016).
    • Target Microcontroller: ATmega328P on Arduino Uno (16 MHz).
    • Check Plan: not checkable: vendor standalone Arduino C++ sketch, no upstream package manager.

  • Microchip DAC Driver Library

    • Name: DAC_MCP49xx (header included as <DAC_MCP49xx.h>)
    • Source: Arduino MCP49xx DAC library by Thomas Wink / exupery / Steve Quinn (common community library for MCP4901/4911/4921/4922).
    • Version: Not stated in source code or project documentation.
    • Pinned Status: Unpinned. Code assumes standard constructor DAC_MCP49xx dac(DAC_MCP49xx::MCP4921, 10, 7); and method dac.output(value).
    • Manifest Location: None provided in repository.
    • Check Plan: not checkable: unpinned third-party Arduino library without version manifest.

  • Standard SPI Library

    • Name: SPI (header included as <SPI.h>)
    • Source: Built-in Arduino core library (Arduino AVR Boards package).
    • Version: Bundled with Arduino IDE / AVR Core.
    • Version Source: Not stated.
    • Check Plan: not checkable: standard Arduino IDE built-in core library.

  • Toolchain / Build Environment

    • Name: Arduino IDE
    • Source: https://www.arduino.cc/en/software
    • Version: Not stated in documentation (built during 2016; compatible with Arduino IDE 1.6.x through 2.x).
    • Check Plan: support-status lookup: Arduino IDE 1.8.x / 2.x

Host Software and PC Interface

  • IV Curve Tracer Desktop GUI Application
    • Name: IV Curve Tracer PC Software (Installer.zip and Visual Studio C# source VSProject.zip referenced in directions.md, steps 12-16).
    • Role: Windows graphical application communicating over USB Virtual COM port at 115200 baud (8N1). Sends character 'C' for handshake, receives 'A'; sends 'B' with start voltage, end voltage, and sample counts; parses real-time data stream V<voltage:04d><current:04d>\n; plots up to 5 concurrent I-V curves.
    • Platform / Framework Dependency: Microsoft .NET Framework (version not stated in documentation; noted in directions.md step 12: "Installer.zip (may require .NET framework)").
    • Critical Upload Gap Note: Installer.zip and VSProject.zip are missing from the project files. To operate without the original executable, an operator must implement a generic serial script (Python/PyQt/pyserial or MATLAB) following the serial protocol documented in IVCurve4_27.ino.
    • Check Plan: not checkable: missing proprietary host software binaries and source archive.

Network Exposure and Security

  • Network Connectivity: None. The system does not possess an Ethernet controller, Wi-Fi radio, Bluetooth module, or network stack.
  • Physical Interface: Point-to-point USB-to-UART serial interface (115200 baud) between host PC and Arduino Uno ATmega16U2/FTDI bridge.
  • Listening Services / Open Ports: None (no network exposure).
  • Default Credentials: None.

External URLs and Referenced Downloads

PCB Fabrication and Mechanical Specifications

  • CAD Software / Format: Autodesk EAGLE version 7.5.0 (REVB.brd, REVB.sch).
  • Board Physical Dimensions: 100.00 mm × 80.00 mm (3.937 inches × 3.150 inches) derived from mechanical outline Gerber REVB.GML (bounding box X: 0.2625" to 4.1995", Y: 0.1680" to 3.3176").
  • Layer Count: 2 copper layers (Top copper REVB.GTL, Bottom copper REVB.GBL).
  • Solder Mask / Silkscreen: Standard top/bottom liquid photoimageable (LPI) solder mask (REVB.GTS, REVB.GBS) and white top silkscreen (REVB.GTO).
  • Drill Holes: 142 total plated through-holes across 13 tool diameters (REVB.TXT / REVB.dri):
    • T01: 0.0236" (0.60 mm) - 1 hole
    • T02: 0.0240" (0.61 mm) - 15 holes
    • T03: 0.0320" (0.81 mm) - 47 holes (resistors, signal lines)
    • T04: 0.0400" (1.02 mm) - 32 holes (Arduino headers, DIP pins)
    • T05: 0.0420" (1.07 mm) - 22 holes (OPA549S staggered pins)
    • T06: 0.0440" (1.12 mm) - 2 holes
    • T07: 0.0520" (1.32 mm) - 5 holes (Relay pins)
    • T08: 0.0630" (1.60 mm) - 2 holes (24V and GND wirepads)
    • T09: 0.0700" (1.78 mm) - 2 holes
    • T10: 0.0790" (2.01 mm) - 2 holes (SC+ and SC- test pads)
    • T11: 0.0910" (2.31 mm) - 4 holes (Heatsink retention solder tabs ISO1, ISO2)
    • T12: 0.1250" (3.18 mm) - 4 holes (M3 shield mounting holes)
    • T13: 0.1260" (3.20 mm) - 4 holes (M3 standoff clearance holes)
  • CAM Template: SparkFun 2-layer CAM script (sfe-gerb274x.cam). Production output format RS-274X with Excellon drill formatting.