This is a video of the Gertboard being put through its paces in the Darlington array relay switching tests. There is a Darlington array on the Gertboard that can drive up to six relays. Each can switch 50V and 0.5A. This video shows the program Gert provided to test this functionality (and train us how to use them too).
On the video I talk about relays. In fact I mean Darlington array open collector relay drivers. My bad. ;)
Have you experimented with actual relays as well? I’m looking to power regular 220V lamps but I’m not sure if the 50V you’re mentioning here means that won’t work. Hope you can help. Thanks!
Yes. Here. https://raspi.tv/2012/pi-controlled-light-and-fan-from-mains-power-socket
The 50V is the limit the Darlington array can switch, but that’s the voltage powering the actual relay coils themselves, not the voltage switched by the relay. There are some issues with mains and isolation for safety. The Gertboard will be fine if you hook up the relay properly, but the safety of the rest of the system is important. When I published that page and the video made the Raspberry pi front page, I was heavily criticised for encouraging people to do unsafe things with mains. So be careful. :)
Is it possible to use the gertboard for switching a electric 12V AC door opener ?
If you use the open collector to switch a relay, yes. But you can’t do it directly with the Darlington array for a high current device.