Mum, Can We Use Sound with Ozobot?

Ozobot is a mini robot which we've been having lots of fun with. We've found a way to add sound to our Ozobot play board which uses an adapted version of our LEGO Chariot to trigger sounds.

My kids have really enjoyed adding light shows and trick spots to their play board which are triggered when Ozobot reads coloured stickers at the end of paths. We've been finding lots of fun ways to extend their play.

• See also: Ozobot mini programmable robot review

"Mum, can we use sound with Ozobot?"

One day my 7 year old asked "Mum, can we use sound with Ozobot?". That got me thinking. Ozobot itself doesn't have sound support, but we did have something else that does. We have Electro-mats that can play a recorded sound which a reed switch is triggered by a magnet (Elbrie used one of these with her son to make a talking story board for show and tell.)

We just needed to find a way to join the two together.  A reed switch is an electronic component that closes to make a circuit when a magnet is placed close to it. Well we had been using LEGO magnets with the Electro-mats to trigger sounds. And we had been getting Ozobot to pull along a LEGO Chariot. Aha!

We built an adapted LEGO chariot that incorporates a magnet. We tested that this could trigger a reed switch through the thickness of the play board by driving over it. Success!

Then my boys did a bit of design to see where they wanted the sensors. This could either be on existing paths or in new spots that we could add a path to with grid tape and stickers.

We rearranged the board a bit to move a house into the non-trailer part of the board (where there are structures for Ozobot to drive into without the chariot.) This extended the chariot-accessible part of the board so a sensor could be placed where my son wanted it.

We really appreciated the flexibility of the grid tape and stickers approach at this point. We can easily add or remove paths or change the colour of a sticker to repurpose a path.

Once the design was done we put the sensors in position under a set of Electro-mats. Then we put the Electro-mats under our Ozobot play board with the sensors in place. We've got four sensors in place at the moment but 6 boards (two from another set.) We've got another Electro-mat set which is in use in another project at the moment, but when that's finished with we could add another 4 sensors to give 8 different sounds.

The boys recorded the sounds that they wanted on the Electro-mat (they can easily record different sounds whenever they want to change them.)

My 7 year old played a few notes on his guitar while the 9 year old recorded an 'all aboard' message that's is triggered near the harbour.

Now Ozobot can trigger custom sounds when it drives over the sensors! This works really well.

The Electo-mat control unit also has the ability to power another component for a few seconds when its sensor is triggered. That means we could trigger a motor when an Ozobot drives over a sensor. But that will be a future project.

If you're in the UK you can still get hold of Electro-mats which make this project really easy.

If not, then you could make something similar using reed switches or other triggers and hardware such as MaKey MaKey, Arduino or a Raspberry Pi with GPIO. You'd need to be connected to a computer that can play sound (e.g. via Scratch) or have sound support on the micro-controller you use.

• Next: Ozobot mini programmable robot review