At last, I’ve just finished testing the PowerComms card for our Darwin RepRap machine.
This is the summary of differents tasks during this process.
Getting PowerComms card
Zach has made an excellent job with pushing difficult Darwin parts on a web-shop.
It’s simple and really faster than doing your own PCB cards, but supplies are limited, so I prefer to order parts step by step to give priority to people well more advanced than me in their RepRap building.
Finding componants
I’ve never order any electronic componants on the web, and when I tried to do so on RadioSpares, it was so complicated I preferred to look for help.
After a week, I went to this little electronic shop - Le Comptoir du Languedoc - in the middle of Toulouse, and everything was ready in 10 minutes 
Soldering componants
Zach has made a great video available on RepRap blog where he shows the steps to follow. The only step to take care of is the PCB molex bug, it has to be reverted (5V to 12V position).
Looking for a power supply
It’s time of the century when you’ll find lots of people with dead computers at home, time to use their spare parts. After SMS-spamming all of my toulousian phone directory, Kortex answered first to the announce, and the power supply was retrieved the day after.
Switching on the power supply
Most of ATX power supply you’ll find won’t have a switch on them, this switch used to be connected on the computer motherboard.
You can easily make one yourself. For this, I used an old lamp switch, and connect 2 wires between the green wire and one of the black wire on the big pin plug.
Mac USB Serial connector
I’ve been a bit lost at first with this usbserial cable, a unknown brand one. After connecting it to an ubuntu computer, it was detected as a PL-2303 chipset.
After that, you just need to install one of the PL-2303 drivers for your Mac, and restart the computer.
Just verify you’ve got this file after reboot: /dev/cu.usbserial
Testing card
- Open iTerm (or another terminal)
- sudo minicom -s
- Serial Port Setup
- A - Serial Device : /dev/cu.usbserial
- E - Bps/Par/Bits : 19200 8N1
- F - Hardware Flow Control : No
- G - Software Flow Control : No
- Save setup as dfl
- Connect the usbserial cable, place a wire between Tx and Rx (pin 13 and 14 on max232 chip), and open minicom. If you type on your keyboard, something should appear on the terminal.
- Remove the wire between Tx and Rx, verify nothing appear in your minicom terminal when you type.
- Connect the power to the PowerComms card anb switch on the power supply. If you type something in the minicom terminal, it should appear.
Getting help
RepRap wiki and forums are a big place for information, you should definitely use them in case of problem with your PowerComms card:
