Living room - nRF24
Master Bedroom - nRF24
Kitchen - nRF24
Front room - nRF24
Box room - RPi
Outside - wired to the box room RPi

Want to put one in the hallway, which I guess is the classic place for a thermostat, but unless it's battery powered or right next to a socket it would be very ugly.

I've made loads of changes since but an earlier version is here

https://github.com/ant-thomas/centralheating

It's pretty simple stuff, and can no doubt be improved massively even beyond what I've done since. It's only bash at the end of the day.

Make a wireless one. Mine have been running for nearly 3 months and the batteries have hardly dropped. I should probably set up some kind of alert for when they drop too low.

If I ever get around to making some custom PCBs for them I'll try and find a little box to put them in (NJ) to make them nice and tidy. Have you ordered your PCBs yet?

How long does it take to zap all that with your laser?

That took about 30 or 40 minutes :$

Redid the board, not as pretty but it is functional. Should have made teh solder pads bigger round the pins, but hopefully it's OK. All cleaned, drilled and ready to solder. I think next time I'll just send off to seeed studio :|

https://www.dropbox.com/s/sdj3aik1y4kax3p/2016-03-09%2023.09.31.jpg?dl=0

Looks good :D I couldn't work out what were the traces in your last picture but I can see it now things are connected up. Not used to seeing full copper boards like that.

Is that the way a normal PCB works but with a solder mask over the rest or is the copper just where the traces go?

If you haven't already seen some videos, this guy might interest you - https://www.youtube.com/user/bigclivedotcom

I think he describes his videos as blue collar teardowns. He's recently done a few PCB videos which are quite good.

Not ordered any PCBs, parts haven't arrived to test yet, and I keep having different ideas for design.

What battery do you use? An 18650?

I've had a little look at using a Nokia BL-5C battery because they seem to be the most readily available flat cheap li-ion battery.

I was wondering whether to include a charging circuit, but it would probably be better just to replace the battery with a charged one since they're less than £1 each.

So I'd drop the 4.2V to 3.3V with a regulator, maybe put a voltage sensing bit in like yours to check the battery. I wonder if the ESP8266 can be put to sleep as well as the Arduinos can.

I've seen a couple of his videos, could listen to his voice for hours. Like a posh Kenny.

A NL-5C would be nice to sit under the board. How do you connect up to them and are they only £1? I have a load of 18650 batteries from a dead laptop I'm using.

A regulator drains too much power even when it's doing nothing so best to avoid using one. I've got a diode between one of the output pins and the power input to the radio which I switch on and off when needed, drops the voltage for the radio. I don't think it's a proper way of doing things but it works.

The voltage sensing is all internal to the ATmega chip if it's powered directly from the battery. Nice and easy to do.

All sorts of tweaks you can do and things you can switch off to minimise the power draw when sleeping.

Diode is a nice way to drop the voltage without a regulator. Looking on AliExpress the NL-5Cs are currently 81p. I'd either need to buy some sort of holder/mount which I bet is more expensive than the battery itself, or go for a screw and couple of pins to secure the battery.

I was thinking the same, to have it sat behind the board.

I've got a load of 18650s in a drawer too.

If I didn't have so many 18660s I'd consider getting some of them. Actually I probably have an old mobile I can rip a battery out of to see how well it would work.

Easy method to fix one in place here http://strofoland.com/arduino-projects/nokias-bl-4c-battery-holder-in-just-5-minutes/

ESP8266 modules have arrived. I can already think of a load of things other than temperature sensors that I want to make. Definitely going to end up ordering some more.

Are they little WiFi modules? Easy to use? What else you planning with them?

Once I figured out how to program it, wiring etc, it is now fairly easy.

I'll build a programming board at some point so I can just plug in the USB serial adapter and an esp8266 module.



Once it's programmed you can just power it up without all the buttons and adapters.

Made a quick test setup to see how well my new sketch works.



Pretty simple setup which I might solder to a protoboard

esp8266
ams1117-3.3 regulator module
ds18b20 temp sensor module

Rather than running a webserver on the esp8266 and another system requesting the data, the esp8266 now uses a http get command to send the data itself. This will mean once I tidy up the code I can have it deep sleeping when it's not needed, rather than being awake and ready to send.

Made a programming board



And made a temperature sensor board to play with

 

Turns out the ESP8266 can run off 4.2V so you can connect a lithium battery direct without a regulator to waste energy. 3x rechargeable AAs work well direct. Next step is to sort the deep sleep code.

I've bought some lithium charging boards to use to protect against over discharge. Another few weeks to wait!

Interesting. I didn't realise they could be run on their own. I assumed they needed an Arduino to connect up to. I wonder how well they run in sleep mode compared to an Atmega with RF24 radio connected.