Looks like you can get 10x nanos for ~£16 now.

Possibly even cheaper if you searched a bit harder - http://www.ebay.co.uk/itm/181880011056

Just found 10 pro minis for under a tenner.

http://www.ebay.co.uk/itm/201419551076

Wow, that's crazy cheap. How much do the official ones cost compared to that?

Cheapest I can find the chips on their own is about £1 each. No caps or crystals with that though. My other ones came with all that sfuff but I don't use them, and a DIP socket and reset button.

They're so cheap I pretty much see them as disposable now.

I might see what sort of power a pro mini uses with regulator and all LEDs removed. No USB chip to consume energy either.

Not sure if I posted this before but http://www.gammon.com.au/power is very helpful for power saving.

I have seen that before, but forgot about it!

Soldered up another board with a Li-Ion battery now. It's powering up but not sending the temps for some reason. I'll have to try and fix it tomorrow.

What's it all going to do in the end?

/Exciting stuff/... display a graph.

Screenshot attached of the current one doing its job in my living room. With other bits for turning my water and heating on.

Finally got round to changing my loft door over to reed switch from hall effect sensors. Open and close switches to prevent closing too far or opening too much and killing the motor/winder.

Whilst I was doing it I killed the original arduino, lovely smell of something electronic going pop. I had stupidly soldered the nano directly to the board meaning I couldn't swap it out easily. Tried to unsolder it but it wasn't budging. Ended up making a new board and added female socket headers so I can swap it out and reprogram without disconnecting the whole board.

 (bounce)

Nice work :) What do you use to activate the door? I think you did say. I've realised it's not goot soldering some parts in just in case they need changing. In fact the reason my temp sensor didn't work last night was because the actual temperature sensor on the board has stopped working.

It's made me make some changes to the software though. Before I was manually inputting the DS18B20 address before flashing, I had to reflash if I wanted to change the sensor. Now it finds the address automatically and lights the LEDs if it can't find one.

I've also changed the sensor interval to 5 minutes from 1 so should save 5 times less data now. Too many points on my graph I think.

So I finally have 2 working sensors. Have to decide where to put this one and also change the software on the Pi so it can show data from more than just one sensor.

My two boards side by side.

Does the heat from the electronics impact your readings at all?

Are you buying the wire specifically for this? Looks quite thick.

I've just been using some solid core CAT6 I have spare.

Not sure, doubt it though. It's only running for a few seconds every 5 minutes. The rest of the time it's sleeping and oly using microamps of power. The temp sensor is sticking up above the board too, or I could replace it with a sensor on a long cable to see of it's any different t.

It's cable I've ripped out of an old PSU. Too chunky, need to find something smaller and easier to use.

I've an idea. You could try some spare pieces of CAT6 cable you may have lying around...

 

Will Cat5 do? Don't think I have any Cat6.