a little guy

Mutsu Water Looper

This is some info about my beloved Mutsu Water Looper v2. Unlike the kidney-shaped original, this one is orb-shaped and comes with an infrared remote control. A magnet in the base moves the little Mutsu creature around the tank, which can be filled with water. Mutsu makes adorable squeaks and chirps, and grows from being shy to friendly as you interact with them.

A blue orb, the top half transparent and with a large opening through which you can see several clear plastic coral pieces, and Mutsu themself - a cute fish-bunny hybrid with a blue body, rainbow ears and tail, and a yellow star on their forehead. To the side is the remote, made of blue plastic in the shape of a bend teardrop, with a single yellow button.

Mutsu out of the tank, sitting in the palm of my hand - they're maybe 2cm long. The Mutsu Water Looper box, a blue cube-shaped cardboard box with the logo, a rainbow, and some feature call-outs on the front, as well as a window where you can see Mutsu embedded in the internal plastic packaging.

I'd wanted one of these since I was a kid, and spent months refreshing Mercari daily... and the first v2 to pop up was my dream version, with rainbow ears and tail and a little star on their forehead! New-in-box, too!

Unfortunately the device didn't seem to respond to the remote, so I went on a journey to fix it. With the help of a friend and an oscilloscope, we determined that the problem was that the chip was too old to put out a strong enough electrical signal to turn the IR LED on. Luckily we were able to record the signal itself, weak as it was, and someday I hope to build a brand new replacement.

Until then, Mutsu sleeps, waiting for the day when I can properly care for them...

Remote

Internals

The open Mutsu Water Looper remote, half of it held in my hand with the PCB popped out and being attached to the remote with two wires. The same half of the remote again, but this time just on a flat surface with the PCB in-place.

Components

The surface mount components are 805-sized.

Infrared Signals

When you activate the button in a sequence of long and short presses, a signal of 10 pulses is sent from the IR LED. Each pulse is 1.6ms long @ 30kHz.

Button Presses IR Signal
Short, short, short 001110101?
Long, short, short 010000101?
Short, long, short 010010101?
Short, short, long 010100101?
Long, short 001010101?
Long, long 001100101?