We put on a massive Haunted Circus every year for Halloween, so I built an ESP32-based controller to manage the increasingly insane amount of games, props, and custom lighting audio that makes it all happen.

It can:

• Use up to 4 motion sensors and other GPIO based devices. I find Ultrasonic Sensors actually work pretty darn well in a haunt.
• Trigger up to 4 of pretty much any typical Spirit Halloween, Home Depot, etc prop that has a step pad or try me button.
• Play custom audio, including a beefy amp and lineout for powered speakers
• Sync jaw motion with overridden of props (with an extra MOSFET hooked up)
• Has two higher powered and very protected 5V PWM connectors specifically to make it easy to connect programmable RGB LED strings, servos, etc.
• Has a wireless interface via a hub, so I can monitor everything plus adjust motion range/sensitivity, volume, and other per-prop settings. It's fun to monitor activations from my phone.
• Can be powered with 5.9V-12V barrel jack adapters. And has a fused pass thru VOut so you can plug in the controller and one prop through the same adapter, very common use case to spiffy up a prop with custom audio, lights, etc.
• All of this is programmable via ESP32-S3-WROOM-1-N16R8 Having the extra storage is key for all the audio (and there's an even bigger module, but it was out stock at the manufacturer)

The fortune teller in the second photo is a great example of the controller being used to its fullest. The attendant presses a remote control button to start the sequence. This wakes her up, and she does her movements while playing custom audio synced with her jaw synced to it. Plus extra props on the table go off. Plus it sets off a relay to create a lightning effect. Plus it tells a Pi to display a number in the crystal ball via a pepper's ghost effect.

I had built a much simpler controller last year, and while I love that thing, I really wanted to push myself to actually have proper power regulation (instead of a USB brick), power protection, my own built-in amp instead of DFPlayer, etc. And it needed to get done in time for Halloween, so I put my mind to figuring out how to get AI to help the process.

Over two months I ended up using GPT Sol 5.6 and later GPT Astra via Codex going pretty much every step of the PCB design process:

• Speccing out the functionality
• Initial design and component selection
• Sourcing datasheets, footprints, and 3D files
• Interpreting datasheets (so many datasheets)
• Iterating on and validating the design
• Building schematics in KiCad
• Some help with component placement (I did most of it, in hindsight I probably didn't need to)
• And the craziest thing, 99.9% of this PCB was routed by GPT Astra.

There was a lot involved in getting it to work well enough, particularly anything in visual layout. The general process was to have AI attempt to do the work, figure out where it's struggling and critique it, iterate, and once we had a good workflow, have AI build a skill so it can do the rest of the step on its own. This was critical to getting good results, including having schematics and routing not look like a dog's breakfast.