It has been a while since the last post.
During the last few weeks I have been experimenting with Arduino and I’ve assembled ad little computer for my electric bicycle. As you can see from the photo I am using a 16 x 2 LCD display where I can see some useful information:
- External Temperature
- Distance in Km (data stored in the eeprom so it will stay in memory even when the power is off)
- Speed in Kph
- Battery Voltage
This is just a little experiment and I am really satisfied with the results. I have already ordered a bigger LCD screed (20 x 4) to add more data such as:
- Amps drawn from the battery
- Watt-hours used from the beginning of the trip
- Estimate range left based on Watt-hours used
- Battery temperature
- Trip Distance (can be reset pushing a button)
I have some problems with the current configuration because I am using a hall sensor from the motor to calculate speed and distance. My hub motor has a sort of “clutch” or “freewheel” built in so that when I am not accelerating the motor stop turning and the wheel can still rotate freely. For this reason as soon as I stop accelerating the Kph goes to “zero” and no distance is registered. The solution is simple, I will use a common bicycle computer sensor to get the speed and distance data. If I had a direct drive motor there would be no problem 🙂
Here is a video of the road testing:
I used a voltage divider to measure the voltage with Arduino and despite the delay compared to the Turnigy Watt Meter the voltage is pretty accurate (within 0.08 Volts or less difference).