So, the Riverside School Robo-Sharks made dough-bots this week.
Because every year with a new group of robot-builders, we need to go over some basic electronics before they can design and build a bot. So, we may as well have some fun and do something creative along the way.
The night before, I made two batches of dough – as per Squishy Circuits’ recipe. One batch was conductive dough (with a relatively high acid and salt content) – I left this in its natural colour. The other batch, I prefer to think of as ‘resistive’ dough rather than ‘insulating’. It had vegetable oil and sugar to replace the majority of the water and the salt content. I coloured this batch red so the two types were easy to tell apart.
I used an Arduino to test the difference in resistance between the two batches. Next time, I’ll probably write a simple script in Scratch to act as a graphical demonstration of the difference between the two and also show what happens to its resistance when you squish the playdough (playdough potentiometer, anyone?)…
I had decided to use coin cells rather than battery boxes with wires. Largely because I wanted to make compact, self contained dough-bots that the students could take away. However, the dough corrodes the surface of a coin cell alarmingly quickly. You have been warned…
We kneaded our dough and then arranged some simple circuits first of all to test the materials. The expression on people’s faces when they first see an LED light up when stuck into playdough has to be seen.
Then, we started adding extra layers of resistive playdough around to shield parts of each structure, while adding extra pipes of conductive playdough to add more LEDs to a model where they were needed.
The End Result
Here are a few photos of some of the creations we made – it’s not easy to capture an image that allows enough light to show off the detail of a doughbot while balancing the light given off by its LEDs
Next week – Clay Alien Night Lights…