EasyDAQ as virtual relay device

Posted on
Thu Aug 09, 2012 4:56 am
berkinet offline
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Joined: Nov 18, 2008
Location: Berkeley, CA, USA & Mougins, France

EasyDAQ as virtual relay device

In my house I have a few contactor circuits. These are the type where several momentary contact push buttons are connected to a contactor and any button press will toggle the contactor state. Controlling the circuit from an EasyDAQ (or other similar relay device) is pretty simple, just wire the EasyDAQ's Normally Open relay contacts across the contactor input just like a button. Then, create an Indigo action to close the relay and then release it 0.02 min later.

The problem is that Indigo has no idea of the state of the circuit - especially since it can be changed by pressing any of the connected pushbuttons. However, I found that my contactors had two sets of contacts, one unused. So, all I had to do was wire the EasyDAQ's 5v output through the unused contacts and then back to an EasyDAQ digital input - when the input goes high, the contactor is operated. (It should also be possible to rectify the actual circuit voltage and either pass that through an appropriately sized resistor, or use a simple +5v power supply chip, and then look for that voltage on a digital input.)

The next thing was to try to make this lash-up look like a single Indigo Relay device. For this I used the Meta-Device plugin with the action on On and Off tied to the relay closure (button press) action. Unfortunately, while the Meta-Device would toggle the state of the contactor as desired, the displayed state of the device was useless.

Then, all that was needed was a quick mod to the Meta-Device plug-in to add actions to allow changing the onOffState of the Meta-Device. (See Meta-Device v0.9.7). With that in place, I created 2 triggers to look at the state of the digital input tied to my contactor and set the onOffState of the Meta-Device appropriately.

I now have a true Indigo device that acts just like an Insteon or X10 relay, tracks the state of the circuit, regardless of how it was controlled, and uses EasyDAQ for the control.

This same general approach should work for other similar, asynchronous, control situations.

Posted on
Thu Aug 09, 2012 11:14 am
matt (support) offline
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Location: Texas

Re: EasyDAQ as virtual relay device

Cool and creative setup. Thanks for sharing.


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