New Boards arrived!

This time is the PCB of the Opentherm Interface (v1.0) for Alex and his JeeNode and my Jam Jar Firefly simulator.


The round ones are the JamJarFirely and the rectangular is the JeeNode interface. We've sent them to be produced by Lean, there were some delays but eventually we got them.

Alex mentioned that the Opentherm interface mentions having a loop powered Master and Alex wanted to try and do it with JeeNode. I thought about a version two.
I think that I have the hardware ready but surely a lot has to be done in the jeenode side in terms of software, there are only about 25mW available permanently (about 5V@5mA).
This is my first attempt, I've still just tested it on the breadboard but I think it will work. Here is my initial schematic, the LED on the input is a receive indicator and correct polarity indicator (lights dimly when correctly connected and blinks when receiving).


The rest of the circuit is a programmable shunt regulator with two voltages (the transmitter 7V and 16V since the loop is a current source) and a current to voltage converter (receiver).

Solar Cells testing

This Sunday the sky was clear and the Sun strong, so I decided to check some of the solar cells I had in my components box. I have two types from solarbotics (this one and this other one) and other from pagermotors (this one).


All the cells are up to specification although I only tested them on open circuit voltage, it was too hot and too bright to do a test load. I also have no reason to believe the cells won't perform as specified.
I have two ideas for them:

1. use one or two white bright LEDs and a couple of batteries to build a "light hours" extender for my chili peppers. I haven't decided yet if I'll use a micro-processor or I try to build a fully analog control system. Either way it will be quite complex as it involves two switching power supplies (charge batteries and supply LEDs) and some operation decision. I'll call this project the "Solar-Extender".
   
2. revise the Mousebot to include a solar panel and a couple of rechargeable batteries, this one will definitely have a micro controller. It should harvest the sun and charge his batteries and when the sun is out it should hide in the darkest and coolest place of the house. Put some "simulated annealing" when it wake's up or goes to sleep in order to let him fool around and find some better places. This project I'll call the "Solar-Bug".
   

I hope to finish these two projects before the end of the summer, as from then on either the behavior of both the projects will be pushed to the maximum efficiency as light-hours decrease towards the winter-equinox.