2 replies to this topic

[John C]

Is anyone out there using their Netduino to switch AC? If so, what device are you using? TIA. - John

[bill.french]

I'm using this for my sous vide controller: (i use a transistor to control it from the netduino)
http://powerswitchta...om/default.aspx

I had a 16hr steak and eggs for breakfast! What are you working on?

[Fred]

I'm using a Netduino to control lighting. I decided on a relay to switch the voltage and the usual transistor / fly-back diode to allow the Netduino to power the relay safely. Something similar to this diagram.

The main problem I came across was because I'm switching fluorescent lighting. The kickback as the relay switches off the lights was causing the relay contacts to spark and weld together. A varistor across the relay contacts seems to have solved this.

Another quirk is that the Netduino's outputs are pulled high on startup by the internal pull-up resistor. Enough to openate the relay until my code created the OutputPort object. Adding an external pulldown resistor was the simplest way to solve this.


I also intend to try using an opto-isolated triac switching a power triac when I get the chance. See page 4 of this to see what I mean.