A temperature monitor for the ESP8266

While getting depressed about the firmware for the ESP8266, I happened to be Tweeting and I got a reply from a fellow called Martin – who’s developed a web server for one of the boards, able to read a DHT22 chip (temperature monitor) and put a led on and off – without any other board. I went off to his site to get the materials and sure enough – a pair of binaries and some website code (ie 3 files to blow into the chip.

I followed his instructions – I got nothing at first then realised the board still somehow remembered my router.. so I went off to the last IP address I had for the board and lo and behold…

tmp86CC

I gave it a bit of a hammering including having it send me some code and scrapping that half way through – and it survived. The PROBLEM is that my boards (the ESP-01) have only a couple of GPIO pins brought out – not the lot – so I can’t use this to monitor temperature right now – also GPIO13 is not available on this board – but I am going to ask him to look into hooking up GPIO2 which is currently not used on the ESP-01 boards.. at under £3 for the board and you don’t need anything else other than Power, this HAS to be worth using?

Here’s the link – http://harizanov.com/2014/11/esp8266-powered-web-server-led-control-dht22-temperaturehumidity-sensor-reading/

Looks like he’s done lots of work on the chip!

I’ve tried out his binary code (anyone want to write a tutorial on how to compile this for Windows users – I really do want to mess with this) and even had it running remotely and tested by 2 people at once  – UP TO NOW it’s rock solid. Can’t test the thermal input – would much rather it used one of the Dallas 3 pin sensors.

Here’s what Martin has to say about the ESP-01 board as against ones using a version of the chip with more pins..

Here are my thoughts about usability of the ESP-01

1) The available GPIOs are limited to GPIO0 and GPIO2

2) You need GPIO0 for firmware update mode, this limits the type of things you can connect to it and may prevent firmware update possibility..

3) GPIO2 is used as serial debug during the module boot; mind what you connect there or it may wrongly be activated during start up. Also pulling that low during boot prevents the module from starting.. quite unpleasant

for the above limitations, I’ve decided to go for the ESP-03 version only, the ESP-01 is more intended for interfacing to Arduino projects and not standalone use.

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