Over the last couple of weeks l’ve done a bit more work on my HomePi project. I have now finished the design of the pcb (for the first version). Previously i had been using Eagle to design my pcb’s, this time however i have used Fritzing instead.
While Eagle is very good, its also a bit hard to use, especially if you have not done a lot of electronics work before. Fritzing on the other hand is aimed at novices and is very easy to get to grips with. You can create a virtual breadboard of your project, and based on this it will create you a real schematic and a PCB. There are also loads of template part available online, so building up the project is a simple! Check out the software at http://fritzing.org/.
They also offer a PCB fabrication service, but it doesn’t work out as cheap as using Seedstudio, although (from a European standpoint) you will end up with your board a lot faster. This is an export of my breadboard view:
So, on this board I have the following sensors:
- A DHT11 temperature and Humidity sensor
- A light resistor and capacitor for measuring the current light level
- An LED that can be turned on or of (to be used as a lego street light that comes on at night)
- An Rj45 interface so the device can be extended with 1-wire devices
My HomePi board will be mounted on the top of an Adafuit LCD pi plate using a 45° GPIO header. The LDC plate will have the LCD screen plugged in, and is mounted in the roof of the Lego house. My first (unfinished version) of this is pictured below:
From the Fritzing software, I have also printed out the PCB, backed it on a some polythene packing sheet and mounted all the components on it. I have done this to give me a rough idea of how big the finished PCB will be, and to make sure its going to fit in the house OK. Lucky it looks to be the right size:
So hardware wise, I think I am now ready to get my board made. I still need to do some more work on the actual house, one of my main things with the house is i’m not sure the best way to create my little street light. I have ordered a pre-made Lego street lamp, so I might have to drill some holes in it to get my LED in.
Software wise, I have done a bit more work on the Python script that controls everything. I have tided up some of the code, and it is now hosted on Github, so you can download it yourself and have a play around. At the moment there is no instructions on how to build everything needed for the code to run, but as I need to build an sd card from scratch for the micro sd adapter I am going to use, I will document it as I build. Go and grab the python script now from https://github.com/beakersoft/HomePi