Today with the help of my four year old son Kai, we built a little experimenter’s board because he has been wanting to “learn about ‘lectricty” for a while now.
First I found an old piece of MDF from my shed and cut off a bit about 10″ by 6″. Then I bought some screw eyes from the hardware shop. I already had this bunch of colourful clip leads.
To build it, we drilled some 1mm pilot holes and then screwed in the eyelets with a small washer under each one. Kai loved having a go of a power tool even if it was only a little battery-powered Dremel. The wire from each part gets clamped under the washer as the screw eye is tightened. I used some pliers to screw the eyes in nice and hard so the wire will stay clamped.
I have soldered a current limiting resistor in series with each part. I used 100Ω for each of the LEDs and a 15Ω ½ watt resistor for the motor. These values were arrived at by guesswork, experimentation and whatever I could find in my parts box using the time-honoured principle of “Whatever works man”. I used a little hot-glue to hold the parts in place.
I attached the battery holder to the board with some velcro so it can be easily lifted up to change the batteries.
And here’s the finished product. I still do not have any kind of over-current protection for the batteries. I guess it won’t be long before the child tries to connect the battery terminals together and kills them. I’ll see what I can come up with in the future but for now we are having too much fun to bother about it.
I spent about $2 all up to buy a packet of screw eyes. Everything else came out of my junk box. That is my driving philsophy here. Just use what I’ve got, otherwise, I may as well have spent $50 on a store-bought electronics kit.
The board contains 4xAA batteries, 2 LEDs, a momentary push button and a DC motor. Kai can make up circuits by clipping the clip leads onto the eyelets. I have left some room on the board so we can add other bits on in the future. Its simple and fun enough for a four year old.