1 October 2016

How to use CAN bus relay module Keybox to conduct a massive I/O extension

We sat down with Collin Kidder, CAN bus Protocol Hacker and early adopter of the CAN bus relay module Keybox. Together with his staff at K & K Manufacturing, Kidder has used Keybox for a project for the full electric conversion of a historical automobile: the 1959 Mercedes Benz 190SL. Thanks to Keybox, Kidder was able to significantly extend the car’s capabilities. Now, in addition to a fully electric 100kW engine (UQM PowerPhase 100), the car can boast evolved instrumentation including cruise control and a twelve-key CAN Keypad...


Mr. Kidder, tell us a little more about what you do…

I write software/firmware for electric vehicles and reverse engineer existing OEM components so that they can be used in aftermarket conversions. For instance, the Mercedes project uses a UQM motor and inverter from a Coda car. The Coda company went bankrupt, but left behind a large stock of motors and inverters meant specifically for that car. I figured out how to produce the proper security responses and helped to write code to control the inverter. I've also gotten into doing the actual electric vehicle conversions.

What were you working on when you first discovered Blink Marine?

That project was a 1959 190SL Mercedes Benz that was converted to all electric. We needed a good way to control things like lights and contactors. The car is an antique, so it was very, very basic in terms of electrical connections. They just didn't have much of anything powered back then, certainly not 500A contactors or precharge resistors!

It can’t have been easy to convert a car that’s almost six decades old… How did Blink Marine solutions help you accomplish your goal?

The Blink Marine KeyBox was used to add control to systems that didn’t exist in the 1950's. Keybox helped me add things to the car that the car wasn’t designed for, like:

  • LED turn signals with configurable blink duration and emergency (four way) flashing lights
  • Control of a main contactor
  • Control of the precharge resistor contactor

I could have done some of the things I needed to do with my existing hardware, but I was running out of I/O on the ECU. The KeyBox really helped by giving me a lot of extra outputs that I could easily control over CAN. As a bonus, the KeyBox is also quite small and well-contained so it allowed me to pack a lot of outputs into a small space.

KEYPAD CONFIGURATION: 1. Turtle mode - Drops maximum power down to about 70% 2. Rabbit mode - Full power for acceleration 3. Park - Essentially neutral - No power 4. Reverse - Backward driving 5. Accelerate - Cruise control - increase set speed 6. Decelerate - Cruise control - decrease set speed or set initial speed 7. nr 1 - Light Regen 8. nr 2 - Heavy Regen 9. nr 0 - No Regen 10. Fan - Force cooling fans on 11. Hazard - Turn on four way hazard lights.

I also used the PowerKey PRO 2600 pad. This allowed me to easily add even more things that the car would never have had otherwise. I added cruise control to a 1959 car! The keys were also used for shifting (the car was originally a stick shift and we removed the transmission), to trigger emergency four way lights, and to be able to manually force the cooling fans on. The Blink Marine button faces are much nicer and more numerous than other company's button faces, so we were able to find a set of self explanatory button faces that look really nice.


I’m intrigued by the blend of old-fashioned and futuristic in your Mercedes benz. It reminded me of the cars in “steam punk” literature. Why did you start working specifically on this type of car? What inspired you?

My main business – where I work most of the time – involves making body and frame parts for antique Mercedes Benz and Porsche cars. So we’re really familiar with Mercedes Benzs. Some of

the people here have restored more than 30 190SL cars. You could say we're experts in 190SL restoration. Our close ties to antique Mercedes brought us to the attention of a customer who wanted to do a 190SL electric conversion and had purchased parts to do so. But he was having trouble getting the project done.

1959 Mercedes 190SL fully electric CAN bus Keypad Blend

We talked him into sending us the car and we finished it for him. It was the very first electric car we'd ever touched. This was with lead/acid batteries. The car worked, but the lead batteries were so heavy that they affected performance. So, we got the car back and switched to LiFePO4 batteries. That increased performance and the customer was happy for years. But then, over time electric car technology continued to improve. I had gotten the UQM inverter to work and the customer was looking for more power. The UQM fit the bill, and the batteries in the car were starting to suffer a bit anyway (a few bad cells) so we took the car back, switched to the UQM motor, removed the transmission, and added your KeyBox and PowerKey Pro. This final conversion really did take it in a steam punk direction. Now it is a 1959 car with custom body work, a very powerful motor, and LED push button controls on the dash. It's a very interesting mix of antique and modern.

How are your involved with GEVCU project? Why is the GEVCU Project so important for so many hobbyist and prototype electric cars?

Well, I wrote most of the GEVCU project. It was originally conceived by Jack Rickard of EVTV as a way to have a universal system that could bridge the gap between various OEM components installed in a custom car. The problem was that the Leaf DC/DC converter wasn’t meant to work in a car equipped with a UQM inverter, a Coda charger, and a Blink Marine keypad. It needed something in between all these systems; something that could provide each one the custom messages it needs to make everything work harmoniously in the custom vehicle. GEVCU was developed as the solution to that problem. Jack Rickard produced a design document and a few people got to work making it happen. I'm the main developer for the firmware, but other people wrote some of the code as well.

How Keybox can be used to expand the possibilities of GEVCU?

GEVCU has a set of 8 outputs but they're all low side drivers. This has worked fine for many people, but sometimes it’s nice to be able to switch high side as well. When going to high side there’s the question of "which voltage?" or "which signal?" It’s difficult to satisfy all possibilities. But the keybox leaves the choice up to you. Each output has two wires, and the end user decides what to connect. This is unquestionably the best approach! I used this capability to do some high side and some low side switching with the keybox. Also, I ended up with far more than 8 necessary outputs, so I had to overcome GEVCU’s limits anyway. The KeyBox was a valuable addition both because I needed more outputs and because it is so configurable.

Thank you for your time Collin. One last question before we finish… Are you working on anything particularly interesting right now? And what do you think your next projects will be?

Right now I'm working on a somewhat secret car project, so I can't really tell you anything about that. I’ll be working on one or two more cars in the near future. I think all of them will use the same basic products now that I've got them all integrated. I continue to work on GEVCU improvements and reverse engineer other OEM electric vehicle components. I'm also working to make or find a reasonably priced CHAdeMO station so that I can install more of them in the US. We've got a lot of CHAdeMO stations in the US, but it’s a very big country and coverage is not good. For example, there are no stations within 200 km of where I live. This puts all existing chargers too far away. I'd like to fix that. Also, I have plans to help produce a system that makes it possible to add CHAdeMO to electric vehicles that don't have it. Some testing is already underway for that…

Collin Kidder

Skilled Developer • CANBUS Protocol Hacker • Geek • Gaming Enthusiast

Active in embedded development, Collin has designed both the hardware and software for a biometric safe and a wireless vehicle access control project. He helped design hardware for a vehicle control system, and is currently leading a project to develop open source software for a vehicle control module. Meet Collin on Linkedin.