Monday, October 6, 2014

Frozen Chainsaw Massacre: Ryobi RY40511 Cordless 40V Chainsaw on a scooter

Following up on Charles' blog post here I decided to snag one of these chainsaws for myself and see how it faired in vehicle duty.

The end result:
Chainsaw on a Disney Princess scooter - hence the name
The scooter turned out remarkably rideable, except for the extremely annoying motor controller cut-in behavior, which gave the motor the start-up behavior of a gas engine- if throttle was applied from a standstill too quickly, the motor would cut out, requiring a controller reset. The motor had to be ramped up to speed over the course of several seconds to work properly.

The only way to fix this was to reflash the controller with new firmware. Conveniently enough, there was an unpopulated programming/debug header on the board. We rooted around the board for a while and came up with this schematic:

Next up: port my sinewave controller firmware to the STM8S micro that the board uses.


  1. Working is so cool with Ryobi. Thanks for this sharing.

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