Cheap Asda USB charger + Sensor node

  • So I got one of these things from asda a while back.

    alt text
    alt text
    I opened it up and there was plenty of space for 'things' inside. So I connected a 3.3v regulator to the USB circuit to power a pro mini. On that, I am running the example humidity sensor sketch with repeater mode enabled. Connected to that is a DHT22. I cut a hole in the side for that to poke out of. I also managed to get the pro mini and NRF quite well stuck together. Compact is probably the word i'm after:

    alt text

    alt text

    I tried to keep this away from the high voltage side as best I could. The gap I managed to stuff the pro mini + NRF into is a insulated area, so perfect! I am quite pleased with it.

    alt text

    It did just occur to me though.... the DHT could pick up heat from the USB circuit inside. I'm not sure if it runs warm when in use. I suppose I will find out.

  • Hero Member

    Hi @thazlett144
    ..sounds good... and probably looks good ( but i cannot see the images in your post?!? ) - Can anyone else see them?

    I think you will indeed find that the temperature is off due to the heat generated by the supply... perhaps put the sensor on a short cable ( which wont be as tidy 😞

    If you do put the dht on a cable, be really careful as you may not have the level of isolation you need!!!

    Perhaps, forget the dht, and install a PIR sensor instead. ?

  • Fixed the images. Apologies.

    PIR was what I was thinking doing next. Perhaps more useful. There is not much room for it though.

  • So I got another one of these and made a motion sensor version 🙂
    alt text

    I was thinking about making a multi sensor version of this. I have the sketches for many combinations of multi sensor sketches I have mashed together.