Mega 2560 to Teensy 3.5 Adapter Board

Speeduino Mega 2560 to Teensy 3.5 processor upgrade. Using the Community Gerbers from Josh Stewart’s GitHub with zero changes. They are known to work with Teensy 3.5. See Josh Stewart‘s Teensy demo on YouTube. Bare Teensy 3.5 boards $10 each 04/18/22 Have SMDs to build 12 boards (add $12 per board for unsoldered SMDs). Following is…Read more

The State of the Interface Board Design

The following was an unanswered post on the project Slack channel. Issue not decided, but leaning toward the header solution. 09/18/2021. I am currently using KiCAD to build my interface board from my factory engine bay wiring harness to the Dropbear ECU. I have downloaded the board-mounted connector definition from and placed it on my circuit board design….Read more

Speeduino Drop Bear ECU

The newest product from Josh Stewart’s Speeduino project is finally a production product. It has been in development for over a year. There were four Alpha versions and two or three Beta versions. The chip shortage has affected delivery so I feel very fortunate to have scored one of the first available. Josh’s initial order…Read more

OEM ECU Pinouts

Using the TSRM and TEWD conventions for numbering pins, these are the three connectors on the pre-1989 “yellow plug” ECU for a manual transmission. This is not a change from the original configuration. It is only a documentation correction to make things easier for me to use. The Toyota documentation numbers pins left to right…Read more

August 2021 Update on Supra

Summer in California and my Supra sits outside for the first time in 14 years. It is under cover and on stands at the moment. The landlord at the office complex where I have a commercially zoned garage… almost in a residential neighborhood… has given me permission to park outside for “three weeks”. We are…Read more

Drivetrain Back in My Supra

Great day! Friends (left to right) are Jonathan, Mike and Jessie. Thank you guys, so much. The drivetrain is back in the car. Below is a photo gallery from today’s installation. Sort of makes it look like I wasn’t working, and I must admit, my friends did a ton of work. I definitely could not…Read more

My Teensy 3.6 Upgrade

These are two of my Speeduino ECUs. Difference is basically how each attaches to the car. They have until now ridden piggy-back on an Arduino Mega 2560. That’s an 8-bit machine, and it does the job, but I wanted to do something even more different, and I’m replacing that unit with a Teensy 3.6. I…Read more