Well, that escalated quickly...

A project log for Magnificent Moisture Management

I've got a balcony, tomatoes and a micro controller

Michael HaasMichael Haas 10/23/2014 at 10:050 Comments

I am still looking for a nice valve and an usable servo. For the valve, I went to local DIY stores and was surprised that they're so expensive. I had finally settled on a small 1/2" valve with internal female threading. I still needed some hose fittings for that which where nowhere to be found. Great.

So it's back to eBay.. where I ended up buying an ESP8266 serial-to-wifi interface. Wait, what?

I guess I didn't like the servo and valve offering on eBay and jumped straight from the basics to the fancy stuff. I'll use the ESP8266 to push sensor readings on the 'net. The plan still is to build the MMM (Magnificient Moisture Management) in a power-efficient way. The ESP8266 can draw quite a bit of power, so the obvious thing is to turn it on once a day and upload a batch of collected measurements. From what I read, there is a low power mode (DTIM4) that will draw very little power, but slow down the whole wifi network.

The chip itself is very capable and typically controlled with AT commands over a serial link. The MSP430G2553 only has one hardware UART, so I will have to use a software serial implementation. The wifi chips, or rather the full serial-to-wifi module, is still very new. Some people have translated the Chinese documentations and some projects are surfacing to hook it up to Arduinos and whatnot. The stock firmware is apparently a bit buggy. A GCC variant is available and some people have started using the module as an application processor as well. I am not quite sure if the firmware or the SDK are publically available and under a open license. Still, this is very exciting, and all for 3.05€ including shipping per module. Great stuff.

Here are some links:

My module should arrive in 2-3 weeks. There are at least two versions floating around, and I hope I get the newer one which apparently is more stable.