Motion Sensor (PIR) and Boost Converter

[david_shb]

Hi,

I hope you guys can help with this. I have a MySensor node running on 2AA batteries. It is a motion sensor with one of those cheap PIR modules.

I am feeding the PIR sensor using 3.3V directly to the HIGH pin. So far so good up until here. The problem comes when I try to feed the PIR sensor using a boost converter 0.8-3.3v. With that configuration, the sensor throws tons of false positives.

I attribute it to noise generated by the booster. I have tried adding a 4.7uF capacitor to the power supply but it hasn't helped.

Any suggestions?

Thanks!!

[electrik]

@david_shb try a bigger capacitor
470uF or maybe even 1mF

[david_shb]

Thanks @electrik Are you using a similar design?

[Yveaux]

@david_shb most pir modules are very sensitive to power glitches and require 3..5V power supply.
Therefore I prefer the 3 battery approach as described here : https://forum.mysensors.org/topic/6511/hc-sr501-3-3v-randomly-sends-tripped-when-radio-is-on/23

[electrik]

@david_shb no I'm using 3 AAA batteries without booster.

[david_shb]

Thanks guys, I have one of those modules I will test it out.

I have been playing with a combination of 0.1uF and 10uF. It has been performing decently so far.

Let's see.