re-innovation were behind the original solar car kits used by reaction education. They supply renewable energy and engineering activities for a wide range of educational events. Their main activity is to design, build and race a model solar powered car. The kit includes a number of solar panels, motors, wheels and gears along with a whole heap of general building materials (mainly wood and plastic off-cuts). The participants create a solar car and then take it to the race track to compete against the other teams.

Obviously it is not always sunny here in the UK, so a line of bright lamps are used as a fake ‘sun’. One of the problems with the set-up is the accuracy of the car race times. Obviously if you are going to have a competition, you must have the same parameters for everyone. This was not possible using a stopwatch and flicking the switch. We were asked to help build a new light rig which was easy to transport and had an integrated timer.

In comes an arduino (actually a Xino) and a bunch of other components to try and make an accurate race timer and to display the results. This is based upon the LED dot matrix display, which we are planning on supplying as a kit in the near future.

The main features are:

  • Press button to start the race
  • Count down for race start
  • Switch on external mains supply to start the race (this will switch on the lights)
  • Display the resulting race time

Additional features:

  • A push switch to turn on the lights for 10 seconds with automatic switch off. This stops the lights being left on and getting too hot.

Here is a video of the unit in action:

The unit was built from white plastic plumbing fixtures. This is 22mm waste water pipe. Buy all the parts of the same brand, as I had problems with slight differences in size between different suppliers.

The lights are 400W halogen lights, mounted around 50cm from the ground. This gives enough ‘sun’ to ensure the motors spin well.

A modified AC load timer was used to control the lights from the micro-controller (see separate blog post for full construction details).

The parts were designed to pack away into a reasonable sized bag (which we have not yet made…).

Construction of the rig is pretty speedy:

The arduino sketch is available here.

We will try the light rig out for the next reaction education event and see how it performs. Hopefully we will also get some more video and images of the device in action.

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