4 layers38.1 × 25.4 mm
4 layers61 × 71 mm
Hardware challenge
alienware-sa/harness_tester_challengeHarness Tester Challenge Leaderboard · comma.ai/jobs · Discord · X
- Size
- 61 × 71 mm
- Copper layers
- 4
- Thickness
- 1.63 mm
- Parts
- 25
- Nets
- 142
- Pads
- 290
- Tracks, vias
- 577, 258
- Pours
- 7
- Routed
- Yes
- KiCad
- KiCad 8.0 (file 20240108)
- Created
- 5 Mar 2025
- Updated
- 5 Mar 2025
Overview
Hardware challenge is an open-source printed circuit board by alienware-sa, from the alienware-sa/harness_tester_challenge repository on GitHub, published under the MIT licence. It is a 4-layer board of 61 × 71 mm with 25 parts on 142 nets, routed with 577 tracks and 258 vias.
It is built around the TEENSY 4.1, CY8C9560A-24AXIT and L7805, with the NEO-M8N, ANT-GNSSCP-TH25L1 and ASMB-KTF0-0A306 among its other parts. Its parts include 7 capacitors, 5 ICs, 4 resistors, 3 diodes and 2 connectors. It belongs with the NXP (LPC, Kinetis, i.MX RT) boards of this library.
Main components
9
TEENSY 4.1
Development Boards & Kits - ARM ModuleSparkFun ElectronicsUncategorised
CY8C9560A-24AXIT
TQFP-100TQFP-100(14x14) I/O Expanders ROHSInfineon TechnologiesI/O Expanders
L7805
TO-220ST0℃~+125℃@(Tj) 1 1.2A 20V 2V@(1A) 42uV 500uA 5V 73dB@(120Hz) Fixed Positive Short Circuit Protection TO-220ST Voltage Regulators - Linear, Low Drop Out (LDO) Regulators ROHSOSENVoltage Regulators - Linear, Low Drop Out (LDO) Regulators
NEO-M8N
Uncategorisedu-bloxANT-GNSSCP-TH25L1
-1.575GHz、1.602GHz 1.7、2.1、5.6 3.5dBi、4dBi、4dBi 8W Ceramic Antenna - Antennas ROHSLinxAntennas
ASMB-KTF0-0A306
SMD-4P,2.2x2mm-40℃~+85℃ 10mA、15mA、15mA 110° 2V、2.85V、2.95V 315mcd、725mcd、1.69cd 465nm~474nm、521nm~529nm、618nm~628nm 467nm、518nm、628nm 48mW、66mW、66mW Common Anode Red, Green, Blue SMD-4P,2.2x2mm LED Indication - Discrete ROHSBroadcom LimitedLED Indication - Discrete
PMEG10020ELRX
SOD-123W-65℃~+150℃ 100V 150nA@100V 2A 830mV@2A Independent SOD-123W Schottky Diodes ROHSNexperiaSchottky Diodes
SMAJ16A
DO-214AC(SMA)-65℃~+150℃ 15.4A 15.4uA 16V 17.8V 26V 400W TVS Unidirectional DO-214AC(SMA) ESD and Surge Protection (TVS/ESD) ROHSLittelfuseESD And Surge Protection (TVS/ESD)
SISS27DN
PowerPAK1212-8S-50℃~+150℃ 1 P-Channel 2.2V 30V 4.6mΩ@10V 485pF 5.25nF 50A 530pF 57W 92nC@10V P-Channel PowerPAK1212-8S MOSFETs ROHSVishay IntertechnologyMOSFETs
README
README.mdHarness Tester Challenge
Leaderboard · comma.ai/jobs · Discord · X
We (mock) designed a simple harness testing PCB and wrote some firmware for it. Unfortunately, this board was designed and firmware was written on a Monday morning.
Can you figure out everything wrong with it?
The Harness Tester
We currently sell hundreds of car-specific harnesses to users every month, consisting of close to 40 different types.
As a simple wiring harness, we expect them to have a near-zero failure rate. For this, making sure that the harness wiring matches the designed diagram for each unit we send out is vital. This tester is designed to be capable of quickly verifying which pins are connected to which other pins.
A quick list of design goals is listed here:
- 12V DC input with transient and reverse polarity protection
- compatible with harnesses with up to 40 pins (through a pin header)
- start button and RGB LED are the user interface
- microSD card to store test results along with the current time (for statistical purposes)
- receive time by acquiring a GPS lock (ok, yes, this is just to make the board and firmware more interesting)
The challenge
The challenge consists of 3 distinct parts, each riddled with a few bugs:
The web views are made possible thanks to KiCanvas!
The board is designed in KiCad 8, a free and open source EDA tool. The full project is available in an exported archive.
There are a handful of intentional, show-stopping bugs hidden in each part (we're not looking for potential points of improvement). Find them, and send them over to us for verification!
Parts
25| Qty | Value | Footprint | References |
|---|---|---|---|
| 4 | 100n | Capacitor_SMD:C_0402_1005Metric | C2, C3, C4, C5 |
| 2 | 4k7 | Resistor_SMD:R_0402_1005Metric | R2, R3 |
| 1 | 10k | Resistor_SMD:R_0402_1005Metric | R4 |
| 1 | 10u | Capacitor_SMD:C_0402_1005Metric | C7 |
| 1 | 12V INPUT | Connector_BarrelJack:BarrelJack_CLIFF_FC681465S_SMT_Horizontal | J1 |
| 1 | 12n | Inductor_SMD:L_0402_1005Metric | L1 |
| 1 | 1k | Resistor_SMD:R_0402_1005Metric | R1 |
| 1 | 1n | Capacitor_SMD:C_0402_1005Metric | C6 |
| 1 | 1u | Capacitor_SMD:C_0402_1005Metric | C1 |
| 1 | ANT-GNSSCP-TH25L1 | gnss:ANT-GNSSCP-TH25L1 | AE1 |
| 1 | ASMB-KTF0-0A306 | LED_SMD:LED_ASMB-KTF0-0A306 | D3 |
| 1 | CY8C9560A-24AXIT | Package_QFP:TQFP-100_12x12mm_P0.4mm | U4 |
| 1 | Cable header | Connector_PinHeader_2.54mm:PinHeader_2x20_P2.54mm_Horizontal | J3 |
| 1 | L7805 | Package_TO_SOT_SMD:TO-252-2 | U1 |
| 1 | MAX2679 | Package_BGA:WLP-4_0.83x0.83mm_P0.4mm | U5 |
| 1 | NEO-M8N | RF_GPS:ublox_NEO | U3 |
| 1 | PMEG10020ELR | Diode_SMD:Nexperia_CFP3_SOD-123W | D2 |
| 1 | SMAJ16A | Diode_SMD:D_SMA | D1 |
| 1 | SiSS27DN | Package_SO:Vishay_PowerPAK_1212-8_Single | Q1 |
| 1 | TEST BUTTON | Button_Switch_SMD:SW_SPST_PTS645 | SW1 |
| 1 | Teensy4.1 | teensy:Teensy41 | U2 |
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Questions
How big is the Hardware challenge PCB?
It measures 61 × 71 mm and has 4 copper layers, 1.63 mm thick.
What parts does the Hardware challenge use?
25 parts, built around the TEENSY 4.1, CY8C9560A-24AXIT, L7805 and NEO-M8N. The full list of its parts is on this page, with links to each part's symbol and footprint where PCBKit's library has them.
Where can I download the Hardware challenge KiCad files?
From the alienware-sa/harness_tester_challenge repository on GitHub, at the commit this page was made from: the board is kicad_files/hardware_challenge.kicad_pcb and its schematic kicad_files/hardware_challenge.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the Hardware challenge design in my own project?
Its repository publishes it under the MIT licence: you may reuse it on that licence's terms (keep the author's notice, and for a copyleft licence share your changes alike).