Tomobell — a doorbell for friends.

Making a plan with a friend is a skill. "Can I come over after school?" — asking, being told no, trying again. Children used to practise it by knocking on a door. Today, almost every plan goes through a parent's phone.

Tomobell gives that step back to the child. It is a doorbell for the home — not a device of her own. She puts a friend's little house on the home spot and pushes the bell; at the friend's home it chimes, and the two of them talk. Because it stays in the room, she makes the arrangement herself while a parent is still within earshot to help when she needs it.

It is a communication device without the parts of a smartphone that worry parents: no screen, no feed, no apps, no browsing, no number to hand out. Only people both sets of parents have approved can ring.

The first Tomobells are due to ring in 2027.