Hardware

I had a discussion with a friend of mine on Why the hell are you designing a new PCB instead of buying one ? He is right: there is a lot of great cheap boars like Moteino, Anarduino, Jeenode… But on the other side:

1. I like to learn.
2. Some of them are expensive compared to a full DIY solution.
3. It is not so difficult: it is just an ATmega, an RF chip, an optional voltage regulator and some passives selected to optimize power consumption.
4. Adapted to my needs (RFM69hw, dedicated footprint for some sensors, form factor, regulator, connectors…).
5. I am not reinventing the wheel, so I will use libraries from these boards.
6. Regarding firmware they have done a great job, but I did not found it flexible enough or too complicated for my needs.

Software & IHM

A lot of big softwares, hhis time too, I see the pros and cons:

• Jeedom
  • Good GUI design, looks pretty
  • Only use of MySQL, not really adapted for storing sensors data on a small embedded Linux card
  • Open-source but commercial aspects are really intrusive
  • Not so easy to add a module
• Domoticz
  • Seems more open and lightweight than Jeedom
  • Bad GUI design
  • Seems to be based on SQLite, lightweight but some old test on a Gumstix gave me issues after a few months
• OpenHAB
  • Created to be linked to any modules or database
  • Not lightweight, might be related to the use of Java
  • Bad GUI design for version 1, the v2 seems great.
  • The v2 will be too late for me

Also, I discovered Node-Red which is really easy to use and created “for wiring together hardware devices, APIs and online services in new and interesting ways”, exactly what I am doing. The main drawback is that everything is asynchronous.

Database

On the database side I wanted to try time-series databases which are made to collects metrics, and NoSQL.

• MongoDB with or without cube layer: I heard good things but never tried.
• Graphite: I tried on a Raspberry Pi, it works but it is a complete solution: too big for me, a lot of dependencies and components
• InfluxDB: I like the approach, the v0.9 add ‘tags’ which are good for my application, perform well on the rPi. Maybe a too unstable but I will give a try :)

On the GUI side, I did not found what I want yet, so I am testing Grafana to display data and might use some links inside to start actions until I find something great. I might also do it myself, but I am far away from being a designer so it can be really ugly…