[HH] cheapest/simplest way to control a relay from a PC

[Tom Metro]

Federico Lucifredi wrote:
> I may not have caught all that went in the thread...

The objective was to work around an undetermined hardware/software
problem (cross-talk) with the port multiplexer on an IR transmitter by
running one of the ports through a computer controlled relay, and using
some scripting to force that emitter to be disconnected from the
transmitter when not in use.


> Powerswitch Tail - $25 
> https://www.adafruit.com/products/268
> ...did anyone mention this already?

No, it didn't come up.

The device is basically an enclosed solid state relay with a couple of
120 V pigtail cords - one plug, one socket. Screw terminals to supply
the 3 to 12 VDC control signal. It doesn't include a computer interface.

That's nicely done for $26. Not useful for this project, but could be
handy in the future.

In theory, it should be drivable from the parallel port, per the earlier
discussion. (Though with ~3mA drive, it'll require an external supply,
buffer transistor, or ganging multiple outputs together.)

 -Tom