Hey Megabobra! I'm still running your 1st gen MegaBobra for about 4k now ;-) A friend of mine also rides a Voima, but his motor has issues so it's gonna be replaced under warranty. We swapped his motor with a new one from another bike. Today we're gonna put the Bobra back. So if due to higher software version his Bobra won't work, the only solution is to switch from external to internal? And then "firing" the sensor input on the motor with the Bobra? Cheers Sander.
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MEGABOBRA: Bosch Smart System Derestriction for Rim Magnet - DIY Project with Support
- Thread starter megabobra
- Start date
- Thread starter
- #392
Hey Sander, ha that's outstanding. Did the motor that's being replaced have the megabobra running on it?
Do you mean switch from Rim to Rotor magnet? If so, yes I think that's safest. BUT let me send you a PM
robbydobs
Active member
I was thinking about this the other day as I took magnet off when chaning the valve.
I think the rim magnet is oriented so north-south is tangential to the wheel.
In which case, I think you'd need two coils, a longer one running up/down (as if coiled around the seapost), one running left/right (like you have already).
The up/down one needs to increase, then decrease and produce a strong field.
The left/right one needs to be weaker and incrase, then flip negative and decrease (as this crosses zero, it represents the rim magnet being perpendicular to the sensor)
These two magnetic fields should then add up to simulate the magnet on the rim passing.
I think this is exactly how the Speedfun rim magnet chip works, as there is space for the up/down coil in the longer raised part of the magnet emulator...
I did email about buying one but they aren't available yet.
I may get the bits and attempt to construct something similar with the megabobra schematic. I think the L9110 already has two outputs, so shouldn't be too hard to add another coil.
I think the rim magnet is oriented so north-south is tangential to the wheel.
In which case, I think you'd need two coils, a longer one running up/down (as if coiled around the seapost), one running left/right (like you have already).
The up/down one needs to increase, then decrease and produce a strong field.
The left/right one needs to be weaker and incrase, then flip negative and decrease (as this crosses zero, it represents the rim magnet being perpendicular to the sensor)
These two magnetic fields should then add up to simulate the magnet on the rim passing.
I think this is exactly how the Speedfun rim magnet chip works, as there is space for the up/down coil in the longer raised part of the magnet emulator...
I did email about buying one but they aren't available yet.
I may get the bits and attempt to construct something similar with the megabobra schematic. I think the L9110 already has two outputs, so shouldn't be too hard to add another coil.
- Thread starter
- #394
Yes I think you're on the right track with this. I'd built up a three axis coil for the reasons you state above, but it was wound in a continuous strand so it wouldn't be possible to fire in sequence or with different power levels.
Again yes correct, you can use the second channel of the L9110 to do so.
Keen to hear how you go!
Again yes correct, you can use the second channel of the L9110 to do so.
Keen to hear how you go!
- Thread starter
- #397
Hi Henno,
My original tutorial won't work with that firmware version. That said, I don't expect there's any changes needed to the code, it'd just be the magnet design that needs updating to match the later firmware requirements. Yes you could try the two coils, or otherwise see what inspiration you can take from the couple of commercial solutions that are around now.
My original tutorial won't work with that firmware version. That said, I don't expect there's any changes needed to the code, it'd just be the magnet design that needs updating to match the later firmware requirements. Yes you could try the two coils, or otherwise see what inspiration you can take from the couple of commercial solutions that are around now.
I follow, if you find anything please let me know ( gen 4 cx 13.13.1 valve magnet)
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martyfrommonmouth
Member
How are you getting on with this?
I've only got mine recently on a CX Gen 5 and it works but the spoke magnet is the weak link. I'm trying to work out how to make it more bump proof so that it cannot move at all under any circumstances.
Hey, i didnt order yet i wanted to gather more info while testing bike without chip, and i have just read your post and im glad that chip works good, but not sure that u can use flow app, please update us how it goes, il let you know when i install mine.
martyfrommonmouth
Member
You can use the Flow app - but to be on the safe side I haven't registered the bike on it. I have just done the tuning.
I've had issues so far with the speed sensor and spoke magnet moving which messes the whole thing up. Oh yeah - you need to leave the bike on once you've finished a ride so that it can trick the Bosch algo.
I think all the solutions so far for Gen 5 have different downsides but this one does work.
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Nice, did you bought rs version with top speed of 45kmh, do you ride everyday? So you can update us on detection rate, i will order RS version this week probably, you encouraged me.
martyfrommonmouth
Member
Yeah the RS version. I haven't been detected yet but have had some errors with 523001 speed sensor and in my first ride the 30kmh algo detection cut in. I'll let you know if it changes.
pierrot364
Member
Guys,
I just bought a 600wh battery but I didn't receive yet my bike.
May I kindly ask you to remove your 800wh or 600 wh battery and send me a pictures ? I would like to know which parts or adapters I should screw on the battery to be able to install it on my bike ?
Thank you in advance!
I just bought a 600wh battery but I didn't receive yet my bike.
May I kindly ask you to remove your 800wh or 600 wh battery and send me a pictures ? I would like to know which parts or adapters I should screw on the battery to be able to install it on my bike ?
Thank you in advance!
Philipp
Member
@Evanon I am riding the bikespeed sensor for Bosch Gen4 with rim magnet over 1000km on trails with a Cube Stereo 140 2024 and the sensor is really nice. I had only few times sensor error while riding up a mountain too slow, but this bug is fixed after updating the chip or buying the newest variant. You can also change fast too the original mode with replace the spoke magnet with the orignal rim magnet.
Thank you for all info bro
Hey guys, so i have the gen 4 rim magnet on speedfun. I only get 523003 error on slow pedals or mostly slow uphill pedals but rarely get errors if my cadence is high or faster downhills. I am running 15.12.3 software as i got it new from the shop and they updated it before i got it (smh). I am certain i have installed it correctly with a lot of troubleshooting done. What could cause the error?
Possible reason/ solutions:
- the firmware
- maybe i can run 2 magnets on either end to trick the motor i am doing more revolutions
Possible reason/ solutions:
- the firmware
- maybe i can run 2 magnets on either end to trick the motor i am doing more revolutions
Same for me, sometimes I get the error after 30-60km “constant” 26km/h average and then do a slow speed steep uphill highest gear .
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