I wanted to find a way to get kids:

- moving

- creating

- playing with others

In the end I, and a team of 4 others, built:

- a foam ball with a BLE IMU in it (moving/together)

- an app that allows you to create almost any game you can imagine with AI (creating)

Video of teenagers making a game: https://www.youtube.com/watch?v=-7TZXRBybOE

Video that was intended to be for Kickstarter: https://www.youtube.com/watch?v=Edy9zew1XN4 (we abandoned kickstarter, long story)

For hardware we came up with a pretty awesome custom PCB, based around a Dialog DA14531, that doesnt need any charging for over 500 hours of play. The electronics are encased inside 4.5" diameter of foam. We drove a car over it and it didn't break.

For the app, we are using OpenAI Realtime API (gpt-realtime-2025-08-28) to gather the game requirements via conversation. We are using voice/realtime to allow kids to do it without needing to type or read. This piece has a huge dynamic prompt that flows with the conversation. It has about 20 different tools that the agent can use to access sample requirements, ball data, user profiles, api documentation, etc. We also did a lot of work to require younger kids to have adults present and make sure we never saved any pii, etc.

Then we use Gemini 3 Pro to process the conversation and generate a markdown specification/arhictecture of how the game should be designed. We found that Anthropic Opus 4.6 did perform better here, but Gemini 3 Pro is much cheaper and faster. This has a static/cacheable prompt that is primarily a ball api documentation and details on previously seen issues.

Then we use Gemini 3 Pro to also code the game. A very similar prompt to the specification/requirements just different purpose. We are currently exploring condensing the architecture and coding steps into a single step, with new "thinking" models. Also seeing that Google is launching 3.1 model, literally while I type this...

The end result is an app that allows you to speak game requirements, have ai code the game, then you get to play it with a real physical ball.

So ya, tons of fun building all that. Curious what HN thinks. Now the hard part of maybe getting someone to buy it...

user:	BretJohnson
created:	February 19, 2026
karma:	3
about:	A US expat happily doing life permanently in New Zealand with my wife and 7 year old son who is absolutely living his best kiwi life! Using the big move to launch a new thing, details soon...