[sigplus] Critical error: Image gallery folder photos/2011-marlinespikes is expected to be a path relative to the image base folder specified in the back-end.

A new hardware project: Crazy Volts. Drew and I are working on a fuel gauge for his Crazy Cart. It's based on the ATmega328P + Adafruit's OLED display, and a custom PCB to hold it all together.

The power switch for the cart has 3 leads: ground, battery, and switched to controller. The controller lead is switched and provides the voltage sense, so we just wired the input + power leads together. The display running in the pic above shows our calibration test, and the display itself hasn't been permanently mounted yet.

The design is general enough to be adapted to anything with batteries. In software we'll probably only try to estimate the power characteristics of SLA, but it's just software....

2 layer board of 1.55x2.05 inches (39.47x52.15 mm).

We also considered using a general-purpose ATmega328 breakout (the bduino), or a teensy 3.1 + adapter board to wire up a regulator + OLED display.

I am out of kits and will not restock Wiiceiver due to the lack of good wireless nunchucks available. I am working on Wiiceiver X, a replacement wireless handheld controller & receiver, and can hopefully release specs & instructions in the Spring.

I am also out of "upgrade" kits, but you can also download the latest software and upgrade your own device at your convenience.

Introducing the wiiceiver! A drop-in "plug and play" replacement for a traditional RC receiver, designed for use on an electric skateboard. It has 2 standard 3-pin servo connectors (single ESC, dual ESC, or ESC + BEC) and a port for a Nintendo Wii Nunchuck.

... unfortunately all kits are sold out.

Looking for instructions? click here

I have been asked to deliver a low-voltage disconnect circuit for potential future production. It would drive a 15w load and protect a 12v sealed lead-acid (SLA) battery.


  • Arduino-based ATtiny45v microcontroller
  • preset high/low values at 11.3v and 10.5v
  • An asynchronous banner/Flasher to expose the observed ADC value

I have (finally) made a proper PCB and am offering an LVD / battery saver kit.

This is based on the Custom Arduino-based LVD, but incorporates a 60A N-channel MOSFET. For simplicity's sake, this has a single MOSFET for switching on the ground side. While the components are rated high, it's probably best for relatively low draw (~5A). For high-draw components you can easily use the LVD to fire an automotive electromechanical relay and drive as much current as you like!


A simple, static Stack of int. If you can spare the additional ~1k FLASH for StackArray or StackList, please use them. ATtiny parts are tight on FLASH, and I didn't need the extra functionality.

This is primarily used in Flasher to print most-significant-digit first, and store additional high/low pulses.

An LED "flasher" to expose unsigned int values via single LED, in cases where Serial is unavailable (e.g. on ATtiny parts, or in field-installed modules). This code is used in the Custom Arduino-based LVD

Uses TinyStack for an internal data structure.

Introducing the Commuter Brake:

Tie this around a brake lever to maintain light pressure on the front brake. This immobilizes the wheel and helps keep the bike from moving while propped up in a train or against a tree.

The brake is a short loop of nylon shock cord. Adjust it once to fit, and just slip it on / off as needed. The cord will be tight enough to maintain brake pressure, but also loose enough to allow you to release pressure (squeezing near the top of the hood) to relocate the bike.


for $1 I'll mail you a few. For $0 I'll hand them over, just find me.

Works on any type of handbrake

Compatible with disc brakes!

Emergency Repairs

The Commuter Brake, temporarily repurposed to secure a broken rack.