The trusty alarm clock is a great tool for little kids who insist on getting out of bed very, very early and waking Mum and Dad many hours before it’s time to get up. It’s a simple enough trick. Give the child the gift of a proper, grown-up alarm clock; and inform the child that unless the bell has rung, it is still night-time, and that they should stay in bed.

It works like a dream for some families we know, but this method is a bit less effective with some kids. If you can’t tell the time yet, and if you believe you may have slept through the ringing/that it has been turned off by fairies, you may find your tiny self prone to ignoring your proper, grown-up alarm clock, and jumping up and down on Mum and Dad’s soft parts at five in the morning just because you can.

Blogger and parent Tycen has found a solution for his non-time-telling kid. He spotted this object in a shop for $35, and, like many of us do when confronted with that number, decided he should make one with a Raspberry Pi instead of buying it.

The idea here is that the traffic lights can be programmed: when the light is red, it’s time to be in bed, and when it’s green, it’s time to get up. The yellow light just operates as a night light.

The beautiful thing about making your own version of something like this with your kid is that they’ll become much more invested in it than they might if you just hand over something you’ve bought in a shop. Tycen’s version doesn’t have the moulded plastics, and might not be as pretty as the toy-shop version, but it’s something his son has helped to make, so it’s much more meaningful and precious to him as a result.

Sleepi, ripe for decoration with stickers

The setup’s very simple: basically all this box does is to run a cron job. There’s a button to press at bedtime which turns the light red. Tycen says: “Apart from the watch script on the button, everything else just runs out of cron.  At 6:30 the red light turns off and the orange light comes on.  Then, at 7am the orange light turns off and the green light comes on.  The green light will stay on until you press the button at bed time to turn the red light back on. I put in a cron job to turn the red light back on at 10pm just in case we forgot.”

We love it; the parents at Pi Towers are going to be making their own versions over Christmas. Thanks Tycen! You can find build instructions and code at Tycen’s blog, and a sleepy little boy at Tycen’s house.