Hydra with PIR and Ethernet - interference?

Archive
1

Im making some experiments with my Hydra and the GHI PIR sensor + GHI ENC28 module.

I have a very simple program just outputting to the VS debug console when motion has been detected.
When I only have the PIR sensor connected this works very well.

However, as soon as the ENC28 module is connected with an ethernet cable plugged in, the PIR sensor starts to fire its event randomly.
I found a very simple way to trigger the issue. Reconnecting the ethernet cable makes the PIR sensor fire its event.

What could cause this?
It appears to me as a hardware issue.

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How are you powering your system?

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It’s powered from the USB of my MacBook Pro 2011.
Tried it on another PC as well.

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Have you tried using power source or powered hub?

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I’m actually finding this as well. The GHI PIR sensor seems to “detect” motion every 6 seconds regardless of whether there is or not. I’m using a spider + PIR sensor. Any help would be much appreciated.

This guy also seems to be having the same problem

http://www.tinyclr.com/forum/topic?id=8534&page=1

My app waits 20 seconds for setup and then registers the motion detected event handler. It also ticks every second with the seconds since started.

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Motion detected
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Motion detected
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Motion detected
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Motion detected
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Motion detected
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Motion detected

This is with a cardboard box over the sensor. What’s strange is that it is so regular.

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Are you using hydra as well?

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I’m using the Fez spider

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I go it to work using a PIR sensor off ebay for about £1.99 and soldered it to one of the .net gadgeteer extender boards

(http://www.ghielectronics.com/catalog/product/273)

You can find out which pins need it soldering to by using this;

http://gadgeteer.codeplex.com/downloads/get/273356 (page 5)

Remember this is an X type module (not sure if this matters)

and I used the following code to check the pin status and register an event;

not at machine at the minute, will upload script tonight

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When I disconnect all other modules (or even supply my PIR sensor with power from batteries + a LED that turns on when there’s motion) it seems to work fine though.

I’ll try to order a different PIR sensor.