I got lost when I was seven.

My dad and I had gone out for a walk, the way you do on a warm night, and somewhere in the park I stopped being next to him. It was around ten o’clock. I do not remember how long it lasted. I remember that it was dark, and that I did not know which way we had come from.

A stranger found me first. He walked me around until we found my dad, and my dad picked me up and held on.

It came back to me one day, out of nowhere. Not the being lost part. The other part. What that hour was like standing where my dad was standing, in a dark park, calling a seven year old’s name and getting nothing back.

It was frightening for me. I have always known that. What I had never once considered is that it must have been worse for him, and that the only reason it ended the way it did is that a stranger happened to be walking past.

I could not stop thinking about it. There is a notebook by my bed for whenever an idea turns up, and that night I reached over in the dark and wrote in it.

A phone small enough for a toddler. One button that calls mum and dad. GPS so they can see where their child is, and impact detection so they know if the child falls. A bad idea, written in the dark, and this is where it started.

Two nights later I wrote down a second one.

Put it in the shoe. That was the moment it stopped being a gadget a child has to carry and became something they are already wearing, which is the idea the whole product still rests on. I spent about two months on it and got further than I expected: what happens when a child kicks their shoes off, what happens when they outgrow them, all of it worked out. Then I moved it into the insole and built that.

Mostly on Reddit, at first, and mostly to show them the insole and ask what was wrong with it. Plenty was. Parents of children with autism, ADHD and Down syndrome pulled it apart question by question, and every one of those questions made it better. What happened to me once was something these families were living with every day. One father told me he had turned every lock in the house around to face inside.

And then the part I was not expecting. Almost all of them had looked at the trackers built for exactly this, and almost all of them had closed the tab. The one everybody knows costs between forty five and sixty five dollars a month, forever. One mother told me she had priced it out for her son twice and walked away both times, not because she did not want it, but because some months that money is simply not there.

The technology to keep these children safe already exists. It is just priced so that the families who need it most cannot have it.

Then I emailed manufacturers about making it properly. They came back with two answers. Either it cannot be made thin enough to sit under a child’s foot, or it can, and it costs considerably more than a broke seventeen year old has.

That is when it stopped being a notebook page. The tracker came off the foot and onto a clip, and the rest of the spring and summer went on certification paperwork and factory negotiations, which is not what I expected to be doing at seventeen and is somehow the part I would do again.