I have one of these cheap pir modules hooked up to an atmega328.

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Anonymous
2016-06-20 22:39:56 Post No. 1011684
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Anonymous 2016-06-20 22:39:56 Post No. 1011684 [Report]

I have one of these cheap pir modules hooked up to an atmega328. It is supposed to trigger an interrupt and wake the atmega.

Everything seems to work but when the atmega goes into sleep mode it causes a false positive on the pir module and wakes itself up.

It works fine without sleeping and the interrupt works fine if i use a switch instead of the pir module.

I have removed the voltage regulator from the pir and it now shares a regulator with the atmega.

I assume the problem is caused by some kind of interference on the 3.3v rail but I don't have a scope. What should I do?

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Anonymous 2016-06-20 22:43:59 Post No.1011686
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Anonymous 2016-06-20 22:43:59 Post No.1011686 [Report]

>>1011684

invest in pullup / pulldown resistors

without a schematic we can't say shit

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Anonymous 2016-06-20 22:50:05 Post No.1011690
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Anonymous 2016-06-20 22:50:05 Post No.1011690 [Report]

>>1011686
pull up / pull down resistors for what? i thnk i have them on everthing that needs them, everything works except when i sleep the atmega

i just don't understand why sleeping the atmega seems to be causing interference on the 3.3v

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Anonymous 2016-06-20 22:54:38 Post No.1011695
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Anonymous 2016-06-20 22:54:38 Post No.1011695 [Report]

>>1011690

pulldown for the output

you can add some caps to the power rail.

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Anonymous 2016-06-20 23:00:41 Post No.1011699
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Anonymous 2016-06-20 23:00:41 Post No.1011699 [Report]

>>1011695
i've tried adding a 10k pulldown to the pir out but it made no difference

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Anonymous 2016-06-20 23:02:54 Post No.1011702
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Anonymous 2016-06-20 23:02:54 Post No.1011702 [Report]

>>1011699

show the schematic. want our help? don't make us work for it.