For Disneyland’s 70th anniversary, they released this giant lightup key which contains a pin which you can unlock by inserting the key into various locks around the park. I decided to retrofit the key with an ESP01 running WLED.

Let’s start with a teardown of the key. I was curious what kind of mechanism they decided to use for triggering both the key itself and the lock stations when the key is inserted.

It looks like the key contains an NFC tag which activates the lock station, and the key station has an infrared LED transmitted in the lock which is ready by an infrared receiver in the tip of the key.

Here is a closeup of the 940nm IR 38kHz receiver - either a TSOP1238 or HL-1238. This kind of 38kHz encoded IR communication system is fairly ubiquitous and is often seen in IR remotes for TVs, stereos, etc.

The key implements addressable LEDs on a set of three PCBs. The middle board uses foam to diffuse the light in the shaft of the key, and has a lightbox section for displaying icons representing the individual lands.

The lightbox section employs what looks like a transparency sheet printed with the various icons.

Here’s the disassembled PCB illuminated.

The main board has two ICs - a microcontroller and a flash IC.

The MCU is one from Zhuhai Jieli Technology. Their ICs are fairly common in consumer products like this, and seriously lack publicly available documentation….

The flash conceivably contains the audio samples, and perhaps the LED patterns.

I wired in the ESP01 running WLED to the main board through a switch which enables power to the ESP01, and selects which MCU is connected to the first LED in the addressable LED daisy chain. Annoyingly, the stock MCU switches the power to the LEDs, and turns them off after a set idle period. The MOSFET used to control this must be driven in order to run the LEDs continuously.

The ESP01 and additional wiring can be tucked neatly under the main PCB.