4 layers99 × 53.3 mm
PSLab
fossasia/pslab-hardware
PSLab Hardware Design and Schematics https://pslab.io
199 parts1.7kApache-2.0
2 layers53 × 41 mm
Laser control
mattvenn/laser-controllerlegend 32 ex, coherent C series laser controller
- Size
- 53 × 41 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 16
- Nets
- 18
- Pads
- 61
- Tracks, vias
- 156, 6
- Routed
- Yes
- KiCad
- KiCad 5 (file 20170123)
- Created
- 12 Jan 2017
- Updated
- 17 Mar 2021
Overview
Laser control is an open-source printed circuit board by mattvenn, from the mattvenn/laser-controller repository on GitHub. It is a 2-layer board of 53 × 41 mm with 16 parts on 18 nets, routed with 156 tracks and 6 vias.
It is built around the WS2812B. Its parts include 3 resistors, 3 diodes, 1 capacitor, 1 transistor and 1 switch.
Main components
1README
README.mdEpilog 32 ex usage & control system
Control System
- internet connection to download current valid RFID cards
- enable laser with valid RFID card
- post usage to net every minute
- disable laser after X seconds without laser being used
Electronics
-
ESP8266
-
2 channel relay & driver
-
RFID reader
-
ws2812 RGB status light
Problems & Fixes
- Sometimes rfid reader seems to get blocked
- Sometimes laser pulse isn't detected so laser is switched off - fixed by Guillem, was an interrupt issue
- Sometimes relay turns on but laser won't fire - fixed with new pcb (breadboard bad ground connections)
Software
- ESP8266 checks RFID against remote DB
- if valid, light LED
- turn on relay to connect DSUB25 lines 7&8.
- laser DSUB25 pin 7 -> interrupt on pin 14,
- while interrupt is firing post usage to phant
Control reverse engineering
Neither Epilog or Coherent were willing to share the DSUB 25 pinout that controls the Coherent C Series laser model 1138402-AA.
Searching for the DSUB 25 format, only references to ILDA were found.
A board that connects straight through 2 x DSUB 25 was designed in Kicad and milled
After finding system ground, all pins were tested with laser on and off:
| Pin | Laser On | Laser Off |
|---|---|---|
| 1 | 0 | 0 |
| 2 | 0 | 0 |
| 3 | 5 | 5 |
| 4 | 0 | 0 |
| 5 | 0 | 0 |
| 6 | 5 | 5 |
| 7 | 5->0 | 0 |
| 8 | 5 | 5 |
| 9 | 5 | 5 |
| 10 | 5 | 5 |
| 11 | 5 | 5 |
| 12 | 5 | 5 |
| 13 | 0 | 0 |
| 14 | 5 | 5 |
| 15 | 5 | 5 |
| 16 | GND | GND |
| 17 | 0 | 0 |
| 18 | 0 | 0 |
| 19 | 0 | 0 |
| 20 | 0->5 | 5 |
| 21 | 0 | 0 |
| 22 | 5 | 5 |
| 23 | 5 | 5 |
| 24 | 5 | 5 |
| 25 | 15 | 15 |
Only pins 7 & 20 seemed to have any change when lasing. Also thought that they would be a differential signal. Cracking out the scope gave these results for rastering, lasing at 50% power and 100% power.
Scope channel 1 is pin 7, channel 2 is 20.
Breaking connection to either pin 7 or 20 made no difference, only breaking both lines stopped the laser.
Also tested was breaking pin 4 as ILDA showed that as being the interlock signal, it made no difference.
Parts
16| Qty | Value | Footprint | References |
|---|---|---|---|
| 2 | 10k | Resistors_ThroughHole:Resistor_Horizontal_RM15mm | r1, r2 |
| 2 | CONN_01X08 | Pin_Headers:Pin_Header_Straight_1x08 | laser1, rfid1 |
| 2 | D | Diodes_ThroughHole:Diode_DO-41_SOD81_Horizontal_RM10 | D1, D2 |
| 1 | 330r | Resistors_ThroughHole:Resistor_Horizontal_RM15mm | R1 |
| 1 | CONN_01X14 | Pin_Headers:Pin_Header_Straight_1x14 | esp-con1 |
| 1 | CP | Capacitors_ThroughHole:C_Radial_D5_L6_P2.5 | C1 |
| 1 | Q_NPN_EBC | Housings_TO-92:TO-92_Inline_Wide | Q1 |
| 1 | RELAY_2RT | fp:relay | K1 |
| 1 | ws2812b | fp:WS2812B | led1 |
The 12 most common of 16 parts.
Questions
How big is the Laser control PCB?
It measures 53 × 41 mm and has 2 copper layers, 1.6 mm thick.
What parts does the Laser control use?
16 parts, built around the WS2812B. 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 Laser control KiCad files?
From the mattvenn/laser-controller repository on GitHub, at the commit this page was made from: the board is control-board/laser-control.kicad_pcb. PCBKit opens the board in the browser, with nothing to install.
Can I use the Laser control design in my own project?
Its repository states no licence, so its author keeps all rights: ask mattvenn before reusing the design.
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