JSK-koubou Packed a Full Smart IR Blaster Into a Walnut Shell

Most snack bowls never see this kind of afterlife. Maker JSK-koubou split a walnut along its natural seam, finished the meat, and then spent at least a few hours of careful shop work turning the empty halves into a living room remote that talks to air conditioners, TVs, lights, and fans.

Small neodymium magnets perch on the inside of that seam, resulting in a lovely clear click when you snap the two halves shut. A Seeed Studio ESP32-C3 lies in the center, twisted around so that its USB port sticks out, allowing you to charge it and do firmware upgrades. Because there is so little space, we simply glued an infrared receiver module to the microcontroller. A small magnet wire connects to a tactile switch, a lithium polymer cell, a temperature sensor, and a slew of IR LEDs we’ve placed around the shell. A MOSFET stage provides enough power for the LEDs to send infrared signals across a room.

Once that walnut connects to your home WiFi, the ESP32 displays a basic webpage on your phone. With a single tap on that webpage, the nut activates the codes it has learnt for whatever device still utilizes an outdated remote. A cloud API can do the same function from outside the house. Because the board can capture signals from a variety of existing remotes, you may use a single shell to cover multiple brands without cluttering up your coffee table with plastic clickers. The room temperature is simply sent over the same radio link, allowing the air conditioner to begin running before anyone enters through the door.

Assembly is patient work more than exotic work. The shell is machined and cleaned so that the boards and battery may fit in. We used surface mount components to keep the stack small. Magnet wire replaces all of the cumbersome hookup cables. After loading the firmware, he measures the power usage to ensure that the small cell is not asked to do more than its share. For practical everyday use, JSK-koubou created a 3D printed case version of the same circuit, which is essentially the twin of the walnut showpiece he presently has sitting in the living room, serving as both an adornment and an appliance. A grocery shop walnut fashioned into a WiFi node still appears edible.
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