Photomarker
About the Photomarker PCB
Photomarker is an open source PCB design by SheinbergLab, published on GitHub under the MIT license. It is a 2-layer board measuring 50 × 34 mm, with 22 components from 14 distinct parts.
Other key parts include the OPT101 and LM393. By type, the board carries 14 resistors, 3 capacitors, 2 ICs, 2 connectors and 1 diode.
From the project
Data server system for data acquisition and control
A per-rig photodiode board that timestamps stimulus light onset two ways at once: an analog waveform into an MCP3204 channel, and a comparator edge into a dserv DI pin (IRQ-latched with a box-clock stamp, so it beats the ~100 µs ADC scan quantization).
Wire both. The digital edge is your routine per-trial timestamp; the analog trace is how you verify the edge means what you think, because a fixed voltage threshold lands at a different fraction of the transition for black→white than for a gray-to-gray change.
Main components on the Photomarker
Photomarker bill of materials (BOM)
22 components, 14 distinct parts — part numbers from the project's BOM.
| Qty | Part | Footprint | Refs |
|---|---|---|---|
| 1 | OPT101 | DIP-8_W7.62mm | U1 |
| 1 | LM393 | SOIC-8_3.9x4.9mm_P1.27mm | U2 |
| 1 | JST-PH 5 | JST_PH_B5B-PH-K_1x05_P2.00mm_Vertical | J1 |
| 1 | DNP 1x05 | PinHeader_1x05_P2.54mm_Vertical | J2 |
| 1 | DNP LED | LED_0805_2012Metric | D1 |
| 2 | 100n | C_0805_2012Metric | C1, C2 |
| 1 | 3n3 C0G | C_0805_2012Metric | C3 |
| 1 | 39k | R_0805_2012Metric | R1 |
| 3 | 10k | R_0805_2012Metric | R2, R4, R11 |
| 1 | 270k | R_0805_2012Metric | R3 |
| 1 | 100R | R_0805_2012Metric | R5 |
| 5 | DNP | R_0805_2012Metric | R6, R8, R12, R13, R15 |
| 2 | 2k2 | R_0805_2012Metric | R7, R14 |
| 1 | DNP 1k | R_0805_2012Metric | R9 |
Photomarker design files
The KiCad project lives in the SheinbergLab/dserv repository on GitHub; these links point at the commit this page was built from.
Photomarker: common questions
How big is the Photomarker PCB?
The Photomarker measures 50 × 34 mm, has 2 copper layers and is 1.6 mm thick.
How many components are on the Photomarker?
22 components, from 14 distinct parts, with part numbers taken from the project's own BOM. The full bill of materials is listed on this page.
Where can I download the Photomarker design files?
From the SheinbergLab/dserv repository on GitHub, which has the KiCad layout, the schematic and the BOM; the links under Design files point to each one.
Can I use the Photomarker design in my own project?
Yes, under the terms of its MIT license, which SheinbergLab chose for the repository.
