- 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...
BretJohnson•41m ago
One glaring call out for me as a parent looking at the product itself -- the in app purchase. Wanted way more clarity around those.
For instance it wasn't super clear how many credits would typically be used when creating and dialing in a game (my 7 year old is unlikely to be super efficient in prompts!)
The biggest issue though was I couldn't find the cost of in-app credit purchases listed anywhere. I wouldn't go near a product like this without being able to wrap my head around the scope of on-going costs.
Perhaps highlighting the existing number of free-to-play games would show the value proposition apart from the AI coding aspect. Better yet, provide a way for potential buyers to explore that database and see for themselves how many great, diverse options exist?
Site looks great and really made me want to give it a go.
Cheers from New Zealand...where I'll either consider myself on the waitlist for international delivery, or add it to our 'ship to parents and pick up when in the US list'
-Bret
klangdon•25m ago
It is true we need to be more clear on the game credits.
Currently you can create 20 games with cost of the ball. Then it is $5USD to create 10 games and $6USD per month for unlimited games.
You can remix/improve any of those games for free. The cost of this component is a little unknown to us.
We really are only looking to only cover our AI token costs on game creation. This will likely change if we add text only ability to create games. Right now the realtime/voice part of it is like 80% of our cost.