Bionx - Removing the speed limit with BigXionFlasher
This morning I reset my BionX system to remove the speed limit. With my current gearing, the maximum speed I can go is about 25mpg, but honestly, I wouldn't want to go much faster. At full-assist, the bike quickly gets up to speed and stays there with little effort. At lower assist levels, the bike acts just like it always does, with the assist matching my effort.
Following the directions for the BigXionFlasher, I purchased a Crumb128 5.0 from chip45.com in Germany. I also purchased a male HR30-6J-6P hirose connector and a female HR30-6P-6S hirose connector from DigiKey. Everything showed up yesterday, so this morning I sat down and started soldering. I used an extra ethernet cable with the extra pair removed, since the Cat5e cable was 4-pair and I only needed 3-pair.
The pins on the hirose connectors are really small; it was necessary to tin the wires on the cable long and then cut them to length, about 3mm. I also pre-tinned the pins on the connector. That made the actual connection of the cable to the connector relatively straightforward. This took about 90 minutes to prep everything and do the work.
Following the directions, I checked the cable to make sure it worked. When it did, I cut it and soldered in the Crumb128 board according to the diagram on the BigXionFlasher website. This took about 30 minutes and was pretty straightforward. I only cut the cables to pins 2, 4, and 6, leaving pins 1, 3, and 5 connected. This made for less soldering since the odd number pins are pass through; they don't connect to the Crumb128.
After that, flashing the board with the firmware was pretty easy. Windows 7 did not automatically install the driver for the CP2120 USB to UART Converter from Silicon Labs and install it manually. After that, though, everything went smooth. It took about 10 minutes to get the board connected to my PC and flashed. From there, I connected it to my BionX system. The cable from the console connects into one side of the Crumb128, the cable from the battery connects to the other. Everything loaded and a few seconds later I got a message saying my speed limit was off.
The directions on BigXionFlasher seemed difficult to follow, but once I had all the parts in hand, it made a lot more sense. This was a pretty easy project, all in all. The worst parts were waiting for the Crumb128 from Germany (and even that didn't take too long) and soldering the pins on the hirose connectors.
I don't plan on doing 25 very often, but there are some busy intersections on my commute where I have to take the center lane or the left lane. Drivers seem ignorant of my right to use the roads and can be unpleasant to deal with at times. It'll be nice being able to move through those intersections at a speed more closely matching traffic and then drop down to normal cruising speed.
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