[Semibug] Cheap temperature / humidity / switch

[Mike Wayne]

As some on you know, this has been an ongoing issue for me. I
really want to find CHEAP temperature sensors that I can put
on my local network.

At the moment, the closest I have found is the stuff from Sonoff.
Switches, temperature, humidity -> WIFI
   http://sonoff.itead.cc/en/

These things start at just over $5 for just a switch. I do not
believe that you can get any inputs on the cheap ones; the 
components are not on the PC board.

The TH10 (10A switch) is just over $8 and a temperature probe
adds $2.31 putting it pretty close enough to my <$10 goal. I just
ordered several from E(vil)bay:
   http://stores.ebay.com/mobilekits-Center/_i.html?_nkw=sonoff&submit=Search&_sid=1106796037

In addition, the company permits end users to replace the firmware
so no cloud is needed. Lots of options are available. Once the f/w
has been replaced, it can even be upgraded over-the-air. Here are
two that look interesting:
   https://github.com/arendst/Sonoff-Tasmota	- this is what I plan to try first
   https://github.com/KmanOz/KmanSonoff

If you need bigger firmware, there are even tutorials on how to
replace the off chip RAM.

Or, if you don't want to replace the firmware:
   https://blog.ipsumdomus.com/sonoff-switch-complete-hack-without-firmware-upgrade-1b2d6632c01

It's overkill for my initial project - I don't need the switched
output but it's cheap enough that I'm willing to try it out.

The input can be hooked to all sorts of things, you simply
have to make your own cable.  

They also sell a waterproof case.