Category Archives: raspberry pi

Nut dispenser – 1. Concept

With our squirrels and jays becoming a bit more used to our presence I though it would be fun to create an automatic feeder. Rather than simply dispense nuts the idea was to get them to work for it and to see what they see in terms of colours. Initially this consisted of a coloured l.e.d. that showed if a nut was present (e.g. red for none, green for present etc) with the nut being obscured so they could only tell via the colours.
I have grown this idea in my head to the point where I thought it would be fun to construct a dispenser that had several functions and then use them in a modular fashion to create various scenarios for the creatures to go through before they received the prize.

This idea was left for a while until my niece & nephew gave me a bird house for my birthday – unfortunately it is not possible to put up a permanent bird house in our communal gardens but the shape of it made me think that I could build my dispenser inside – so I did!

birdhouse
The birdhouse that will house the feeder

The following posts show how I am going through the design and build of this project.

Raspberry Pi Breakout board

I’ve spent a few days relearning how to solder and put together a small project for my raspberry pi – a breakout board.

The idea is to have the GPIO pins easily accesible whilst providing each with a bit of protection from mistakes when wiring – specifically to have each behind a resistor as well as a zener diode to stop passing too much current through the pin (check out the links below for a more accurate description!)

Pi working
This pic shows the board and pi connected and working

It is designed by Mike Cook (the same chap who did all the interesting stuff for the BBC B in micro user) and he has full instructions on his website here

He also has some excellent further projects and really handy information about the pi – well work keeping an eye on his site for further updates: website

I have made a couple of very minor alterations so that I can use the materials that were to hand – Mike’s version has a very neat wire layout however I didn’t have anything thin enough to allow for 2 connections in the same hole – hence the messy and multicoloured wires!

Board and pi connected
This pic shows the Pi sitting on the spare section of the new board. I was using it to carry the pair around & was going to chop it off however it sits there quite nicely.
(I’ll give it a try and see how useable it is when it has the cables plugged in).

Its a simple project and I thought that it would handy to teach me how to get soldering and read circuit diagrams – in the end it worked perfectly however it was let down by my rubbish soldering skills and general poor level of quality control.

The board and pi in the connected position. I’m really pleased that I’ve left enough ribbon cable to give good access around both the board and pi – my HDMI lead is short so it all has to be balanced close to the tv.

(I’m not going to show a photo of the back as it looks like a baby transformer has spluttered his solder based dinner all over i!t)

At least I’ve now learnt how to trace faults and rectify them as well as use my meter and soldering iron more effectively. As with all things Pi I bought it to tinker with and to enjoy learning new skills and it has not disappointed.

Pi experiment 1 – dice

Based on an article in the latest magpi online magazine – http://www.themagpi.com/ I’ve had a go at using the GPIO to control LED’s.

After a bit of fiddling around (rectifying my own mistakes with a wrong resistor!)  I managed to get the type in program to work – basically you press the switch then the red LED produces between 1 and 6 flashes to represent a dice.

It was quite tricky to see when the counting started and stopped so with the help of a multitude of websites and python programming guesswork I fitted a further green LED to another of the IO pins. The alteration gives a green light to show it is on. When the switch is pressed the green light goes off and the red LED gives the flashes…. when done it goes back to green.

Its all very basic stuff and laughably useless (!) but I am really pleased that my first step in programing and electronics has resulted in something that works.

Here is a video so that you can witness the excitement (?) in real time:

pi video

and a still of the program itself:

I’m a bit too lazy to retype it so this pic will have to do! – pin 10 is the green LED, with the rest as in the magpi magazine.