In the case of setup mode where it's just a constant repeating pulse, I set a desired speed in code (15kph typically) and then solve for required wheel RPM, milliseconds per revolution and pulse time, being the duration the electromagnet is firing. That pulse time is simply 1/12 of the...
Update on the reversing pulse:
Good news is that I've completed the code changes to run the L9110 driver. These first included the rewrite of how the multiplier behaves at low speeds. In the past, the first five wheel revolutions from stopped just pulsed the coil in unison with the passing...
Yes the dashed line is the field produced by the coil. In fact it switches much faster than the what's induced by the natural analog motion of the rim magnet - I was actually thinking of slowing it down! You can see it's just about vertical vs the slight slope in the blue Bosch line as the...
Quick update. Using the L9110 driver (thanks @tatane for the tip on this) I'm able to produce a reversing coil signal with exponential growth and decay which very closely matches the original Bosch rim magnet profile. Snip below using some data captured using my phone.
I'll incorporate this...
Eeep I'm on Software version 5.17.0 on the drive unit! App version 1.17.2(1037).
I'll spend some time to integrate the + - pulse behaviour on my test bed. I'll come back with an update.
I don't think I'm brave enough to update the drive unit firmware though!!
Anything's possible of course but I'm still a bit skeptical of this. I just think there's too many variables that are unaccounted for. And sure, Bosch want to demonstrate that they're policing the max speed rule for a given market, but surely not at the expense of false positives being thrown...
No not at the moment. I got the driver in case I encountered trouble but didn't need it. I might give one a go on my bench setup to in case I'm actually a long way behind on the firmware...
Hi Frank,
Let me check the version tomorrow to confirm, I'm not sure off-hand, but it must be an older one as I'm not facing those problems.
I actually picked up some L9110S stepper motor drivers to accommodate a reversing pulse but had the need to get it setup. You might find using something...
Hi guys,
I've been running my updated setup with hall sensor and new coil since early December and it's working well. Changes from the original design in the tutorial are as follows:
Addition of small OLED display with two buttons to show simple ride stats and allow for user configuration of...
Hi Frank,
Good to hear your build went well.
When traveling slow, the pulse is 1:1 as you found. Then over the next five wheel revolutions the pulse duration will gradually increase each time as dictated by the multiplier value. However you should not see anything like 1200ms.
It's really the...
The relationship between cadence and rpm really only becomes an issue at slower speeds, being the main reason the megabobra drops back to 1:1 reporting at this point. Reasoning is, for a given rpm, there's only so slow you could realistically be traveling with typical gear ratios. eg If you're...
I just don't need assistance over 35kph, and to reduce unnecessary risk of detection. When you start pushing such high levels of assistance, the current draw from the battery will be significantly higher than what's 'typical', whereby I'd expect Bosch has accumulated SIGNIFICANT data around...
Niiice 2000km, well ahead of me!
Yep, it's the Purion 200. Nice change from the LED remote. Sure, it's super bulky, but only a little larger than the LED, so it was already wasted space. PS don't believe the requirement that you need to take the bike to a dealer to setup the new display - you...
Taking inspiration from Bosch, it'll just be a magnet on the rim with a sensor inside the motor area. Sound familiar? :)
Yes sure, the screen would be optional. My plan is just to attach the female socket to the device, allowing users to decide if they want the screen or not. Could even add the...
Gotcha thanks. Those are reed switches, rather than hall effect sensors. Both detect a passing magnet, but the reed switches do so physically and are susceptible to vibration, and can be a bit particular with orientation. Orientation issues are addressed in the one you linked by the screw mount...