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MEGABOBRA: Bosch Smart System Derestriction for Rim Magnet - DIY Project with Support

manu.w

New Member
Aug 5, 2023
82
39
belgium
LPP and HPP were already active according to the bosch diagnostic program. So Canyon service center doesn't know what is activated and they even said it was not possible to activate.
On my new canyon neuron Bosch performance cx with rim magnet, the lpp and hpp were both factory enabled 12V.
The front and rear lights are not!
 

manu.w

New Member
Aug 5, 2023
82
39
belgium
On my new canyon neuron Bosch performance cx with rim magnet, the lpp and hpp were both factory enabled 12V.
The front and rear lights are not!
Useful picture…

Bosch-CX_MY22_Cabels.png
 

AlumiPro

Active member
May 1, 2023
168
107
California
I’m guessing any of these would work with your system if I don’t want to use the magnet you provide?
I would like to use the Levo magnet,…. provided I can get your sensor wire/reed switch far enough inside the swing arm to align with the magnet!

IMG_6192.png IMG_6189.png IMG_6188.png
 

megabobra

Active member
Jul 24, 2022
229
253
Australia

megabobra

Active member
Jul 24, 2022
229
253
Australia
Useful <Magnetic field calculator>…
Magnetic 🧲 calculator
Hello Megabobra,
What are your coil characteristics?
How far from the motor sensor do you place the coil?
Thanks

Here's the output from that calc using the specs from my coil. In terms of placement, I'm not sure how far inside the motor case the sensor is, so instead my coil is mounted around 30mm from the motor case.

Capture.JPG
 

megabobra

Active member
Jul 24, 2022
229
253
Australia
All devices from the first batch have now been shipped out, spread across eight countries 🥳

For those receiving one, I'm keen to get some feedback and hear about your experiences when they arrive!

For those who are still keen for a device, don't forget you can build your own!
 

megabobra

Active member
Jul 24, 2022
229
253
Australia
Looks like the first few Megabobras have been delivered around the world. Post some photos of your installs once you get them up and running!

And naturally, reach out if you have any questions.
 

bail0ut

New Member
Jul 31, 2023
7
9
UK
Looks like the first few Megabobras have been delivered around the world. Post some photos of your installs once you get them up and running!

And naturally, reach out if you have any questions.
Received today! Unfortunately I won’t be able to install it for another week or so as I’m going away on holiday. I’ll be sure to post pics and feedback when I’m back and have completed the installation.
 

littleleye

New Member
Jun 25, 2023
11
4
the Netherlands
Received mine today! Immediately performed the installation. Steps are easy to follow. The LPP port was already occupied, only the HPP was free as the plug is the same I used the latter.
Unfortunately, my Flow app immediately (in 5-10sec) gives an speed sensor error while positioning the coil on the motor case. After restarting I can try again. I presume the position is correct, as I get an almost instant stable speed. Position of the coil is a bit different than I expected (based on the photos), but the only location that provided me a speed. However, the speed is 13.4km/h, which is probably due to the wheel circumference (27.5 inch vs 29 inch wheels). Still continued installation, to check if it was caused by the lack of physical displacement. Shut off my phone to break connection with the bike. But no luck, during cycling I also get the speed sensor error before I even reach max speed (34km/h). If I mount the rim sensor on top of the Megabobra I do not get the sensor error but max speed fluctuates and is limited to approximately 20km/h. This again tells me the speed sensor and coil is doing something.

Any ideas how I could solve the error?
Could it be the HPP port? Or do you think the positioning is the problem? Firmware version of the drive unit is 8.16.0

IMG_0818.png IMG_0819.jpeg
 
Last edited:

megabobra

Active member
Jul 24, 2022
229
253
Australia
Received mine today! Immediately performed the installation. Steps are easy to follow. The LPP port was already occupied, only the HPP was free as the plug is the same I used the latter.
Unfortunately, my Flow app immediately (in 5-10sec) gives an speed sensor error while positioning the coil on the motor case. After restarting I can try again. I presume the position is correct, as I get an almost instant stable speed. Position of the coil is a bit different than I expected (based on the photos), but the only location that provided me a speed. However, the speed is 13.4km/h, which is probably due to the wheel circumference (27.5 inch vs 29 inch wheels). Still continued installation, to check if it was caused by the lack of physical displacement. Shut off my phone to break connection with the bike. But no luck, during cycling I also get the speed sensor error before I even reach max speed (34km/h). If I mount the rim sensor on top of the Megabobra I do not get the sensor error but max speed fluctuates and is limited to approximately 20km/h. This again tells me the speed sensor and coil is doing something.

Any ideas how I could solve the error?
Could it be the HPP port? Or do you think the positioning is the problem? Firmware version of the drive unit is 8.16.0

Hi Littleleye,
Glad to hear it arrived OK. First thing, don't worry at all about 13.4 vs 15kph - the actual speed displayed in setup mode is irrelevant. I tried to make all units show 15kph (or mph for those markets) but it's tricky given small differences in wheel circumference. In future, I won't worry about this at all. Instead the focus in setup mode is just to ensure the speed shown, whatever that is, doesn't move around.

I haven't tried the HPP but its 12v output is the same as LPP so I bet it's fine. Your trouble sounds like the electromagnet isn't positioned correctly, so try a few things as below:

  • Ensure you remove the existing rim magnet
  • When positioning the electromagnet, ensure you have the white jumper plugged in to enter setup mode. Then move the electromagnet around a little, starting from the location shown in the user guide, to map out the space where the speed reading is stable and where it's not. To be stable, the speed should remain unchanged indefinitely (+- 0.1kph is fine), not just for a few seconds. One you've found the bounds of where the coil can be placed, place the coil in the center of that area and fix it either to the motor casing or to the interior of the frame.
  • Once the electromagnet is fixed in position, ensure you remove the white jumper plug to resume normal mode
  • Assuming you have already mounted the reed switch and magnet on the disc rotor, try spinning the back wheel - you should see normal speed behaviour displayed in Flow/kiox now as the wheel speed increases/slows.
  • If nothing is shown when spinning the wheel or it's unstable, this suggests the reed sensor may not be picking up every revolution of the wheel. Try positioning the magnet so that it passes closer to the reed switch as it rotates. The magnet should pass down the middle of the reed switch as the wheel rotates. If still no luck, you can try twisting the reed sensor 90deg along its length.

The main idea with setup mode is to be able to setup one part of the system at a time. Once a steady speed is displayed in setup, the electromagnet placement is correct and working. Then after removing the white setup plug no speed is shown, or it's intermittent, you know the issue is with the alignment of the magnet and reed switch. So focus first on getting the electromagnet working 100% in setup mode before moving to normal mode.

Rest assured you'll get it running - all setups were tested on my Voima before shipping out!

Let me know how you go!
 

megabobra

Active member
Jul 24, 2022
229
253
Australia
Hi Littleleye,
Glad to hear it arrived OK. First thing, don't worry at all about 13.4 vs 15kph - the actual speed displayed in setup mode is irrelevant. I tried to make all units show 15kph (or mph for those markets) but it's tricky given small differences in wheel circumference. In future, I won't worry about this at all. Instead the focus in setup mode is just to ensure the speed shown, whatever that is, doesn't move around.

I haven't tried the HPP but its 12v output is the same as LPP so I bet it's fine. Your trouble sounds like the electromagnet isn't positioned correctly, so try a few things as below:

  • Ensure you remove the existing rim magnet
  • When positioning the electromagnet, ensure you have the white jumper plugged in to enter setup mode. Then move the electromagnet around a little, starting from the location shown in the user guide, to map out the space where the speed reading is stable and where it's not. To be stable, the speed should remain unchanged indefinitely (+- 0.1kph is fine), not just for a few seconds. One you've found the bounds of where the coil can be placed, place the coil in the center of that area and fix it either to the motor casing or to the interior of the frame.
  • Once the electromagnet is fixed in position, ensure you remove the white jumper plug to resume normal mode
  • Assuming you have already mounted the reed switch and magnet on the disc rotor, try spinning the back wheel - you should see normal speed behaviour displayed in Flow/kiox now as the wheel speed increases/slows.
  • If nothing is shown when spinning the wheel or it's unstable, this suggests the reed sensor may not be picking up every revolution of the wheel. Try positioning the magnet so that it passes closer to the reed switch as it rotates. The magnet should pass down the middle of the reed switch as the wheel rotates. If still no luck, you can try twisting the reed sensor 90deg along its length.

The main idea with setup mode is to be able to setup one part of the system at a time. Once a steady speed is displayed in setup, the electromagnet placement is correct and working. Then after removing the white setup plug no speed is shown, or it's intermittent, you know the issue is with the alignment of the magnet and reed switch. So focus first on getting the electromagnet working 100% in setup mode before moving to normal mode.

Rest assured you'll get it running - all setups were tested on my Voima before shipping out!

Let me know how you go!

Actually also, I just noticed from your photo that your motor looks to be the Performance Line, while the placement I noted in the user guide was for the Performance Line CX - my fault, I didn't realise there was another variant of the Performance Line which still used rim magnet.

In that case, try searching a wider area for the stable speed in setup mode, the motor's hall sensor is probably in a different location vs the CX!
 

littleleye

New Member
Jun 25, 2023
11
4
the Netherlands
Hi Littleleye,
Glad to hear it arrived OK. First thing, don't worry at all about 13.4 vs 15kph - the actual speed displayed in setup mode is irrelevant. I tried to make all units show 15kph (or mph for those markets) but it's tricky given small differences in wheel circumference. In future, I won't worry about this at all. Instead the focus in setup mode is just to ensure the speed shown, whatever that is, doesn't move around.

I haven't tried the HPP but its 12v output is the same as LPP so I bet it's fine. Your trouble sounds like the electromagnet isn't positioned correctly, so try a few things as below:

  • Ensure you remove the existing rim magnet
  • When positioning the electromagnet, ensure you have the white jumper plugged in to enter setup mode. Then move the electromagnet around a little, starting from the location shown in the user guide, to map out the space where the speed reading is stable and where it's not. To be stable, the speed should remain unchanged indefinitely (+- 0.1kph is fine), not just for a few seconds. One you've found the bounds of where the coil can be placed, place the coil in the center of that area and fix it either to the motor casing or to the interior of the frame.
  • Once the electromagnet is fixed in position, ensure you remove the white jumper plug to resume normal mode
  • Assuming you have already mounted the reed switch and magnet on the disc rotor, try spinning the back wheel - you should see normal speed behaviour displayed in Flow/kiox now as the wheel speed increases/slows.
  • If nothing is shown when spinning the wheel or it's unstable, this suggests the reed sensor may not be picking up every revolution of the wheel. Try positioning the magnet so that it passes closer to the reed switch as it rotates. The magnet should pass down the middle of the reed switch as the wheel rotates. If still no luck, you can try twisting the reed sensor 90deg along its length.

The main idea with setup mode is to be able to setup one part of the system at a time. Once a steady speed is displayed in setup, the electromagnet placement is correct and working. Then after removing the white setup plug no speed is shown, or it's intermittent, you know the issue is with the alignment of the magnet and reed switch. So focus first on getting the electromagnet working 100% in setup mode before moving to normal mode.

Rest assured you'll get it running - all setups were tested on my Voima before shipping out!

Let me know how you go!
Thanks for your extensive replies and reassurances regarding most of the questions. I actually did what you explained in all of these bullets. The surprising part is that when I was locating the correct coil position in setup mode the Flow app almost instantly gives this error despite showing a stable speed. Once I’ve got this error I have to restart the bike. I have found the boundaries of the sensor, but on any location within the boundaries I got this error. See screenshot, this is from multiple bike restarts.
I am currently wondering if the elektromagnet could be too strong for my motor type (performance line)? That would mean that if I hold the elektromagnet at a little distance that should work, correct?
I will also try to use the LPP port instead of the HPP port to see if that makes any difference somehow.

IMG_0820.jpeg
 

megabobra

Active member
Jul 24, 2022
229
253
Australia
Hmm can you post a photo of your rim magnet? I wonder if the magnet is different to the CX as well?

Yes next step then is to try positioning the coil back a bit from the motor casing. Maybe put a book or piece of wood between the motor and coil in order to space it back by ~20mm and try again. If that works OK, mounting to the interior of your frame rather than the casing will probably solve the issue.

Also just confirming that you're not using GPS while running the Flow app?
 

AlumiPro

Active member
May 1, 2023
168
107
California
Will the reed sensor pick up a magnet rotation signal if the reed sensor is inside a carbon fiber swing arm? Or was this system built with the intention that the reed sensor would be externally mounted on the inside of the swing arm?
Approx how far away can the magnet be from the reed sensor?
 

megabobra

Active member
Jul 24, 2022
229
253
Australia
Will the reed sensor pick up a magnet rotation signal if the reed sensor is inside a carbon fiber swing arm? Or was this system built with the intention that the reed sensor would be externally mounted on the inside of the swing arm?
Approx how far away can the magnet be from the reed sensor?
Intention is to mount it externally, but if it you can see that it's picking up the magnet, then internally would look neat.

Probably a max of ~20mm separation?
 

AlumiPro

Active member
May 1, 2023
168
107
California
The speed sensor is inside the rear swing arm on my Gen3 Carbon Levo Brose system with a rotor magnet…..guessing it’s using a reed sensor to pick up the rotor magnet.
 
Last edited:

Zimmerframe

MUPPET
Subscriber
Jun 12, 2019
13,883
20,573
Brittany, France
It’s internal on my Gen4 Carbon Levo Brose system with a rotor magnet…..guessing it’s using a reed sensor to pick up the rotor magnet.
Just to check something .......

There's a mix of things there .. Gen4 - would be correct if it was the Bosch Gen4. (gen4 motor)

Levo - would be gen3 (Third generation of Levo) if it was a new one and Brose 2.1/2.2 motor would be correct for the motor.

The megabobra system is designed to work with the Bosch Gen4 Smart System - so if you want something for a Levo you need something like a planet 3 or a levociraptor.
 

littleleye

New Member
Jun 25, 2023
11
4
the Netherlands
Hmm can you post a photo of your rim magnet? I wonder if the magnet is different to the CX as well?

Yes next step then is to try positioning the coil back a bit from the motor casing. Maybe put a book or piece of wood between the motor and coil in order to space it back by ~20mm and try again. If that works OK, mounting to the interior of your frame rather than the casing will probably solve the issue.

Also just confirming that you're not using GPS while running the Flow app?
You cannot run the Flow app and see the ride speed if GPS is not allowed (apple), I thought there was a discussion about that before (see screenshot)? The rim magnet is exactly he same, Bosch offers only one type of rim magnet.

Update on my progress:
Unfortunately I had to give up on the system for now.
Spacing the coil back >20mm results is no signal received, so ruled out that the elektromagneticsignal would be "too strong". Also, changing the HPP to LPP port didn't matter, so ruled that out as well.
Positioning is the real problem, the hall sensor (or some surrounding sensor?) seems to be really sensitive. With a lot of tweaking, I can have the system running in setup mode for 5min with a stable speed output (see screenshot). However, when I mount the motor back, which is awful with all the cables, and try to cycle I do get the same error again. When disassembled, everything seems to be in the same position, but when going in setup mode in without changing the position I get the error within 20 seconds. Repositioning the coil, I get it working again, assembled everything was able to cycle 1 km reached my max speed of 35km/h and again got the error. After the third try two evenings and one morning, I gave up...
The reed sensor is definitely positioned well and working, otherwise I wouldn't have been able to cycle up to 35km/h. But something with the coil positioning is really sensitive. Wonder if having a factory electromagnet (like the one suggested; 5v Electromagnet) with smaller diameter would result in less sensitive placement, as this coils outer diameter is 35mm covering a large part of the range. I think it is worth the try.

@megabobra, do I need to keep the resistors in place? Or can I also just remove the resistors and use a smaller electromagnet? See options: ee table: AliExpress electromagnet. Estimating from the eplus.bike manual, the magnet is quite small.
1692435045786.png


IMG_0824.jpeg IMG_0823.jpeg IMG_0821.jpeg
 

megabobra

Active member
Jul 24, 2022
229
253
Australia
You cannot run the Flow app and see the ride speed if GPS is not allowed (apple), I thought there was a discussion about that before (see screenshot)? The rim magnet is exactly he same, Bosch offers only one type of rim magnet.

Update on my progress:
Unfortunately I had to give up on the system for now.
Spacing the coil back >20mm results is no signal received, so ruled out that the elektromagneticsignal would be "too strong". Also, changing the HPP to LPP port didn't matter, so ruled that out as well.
Positioning is the real problem, the hall sensor (or some surrounding sensor?) seems to be really sensitive. With a lot of tweaking, I can have the system running in setup mode for 5min with a stable speed output (see screenshot). However, when I mount the motor back, which is awful with all the cables, and try to cycle I do get the same error again. When disassembled, everything seems to be in the same position, but when going in setup mode in without changing the position I get the error within 20 seconds. Repositioning the coil, I get it working again, assembled everything was able to cycle 1 km reached my max speed of 35km/h and again got the error. After the third try two evenings and one morning, I gave up...
The reed sensor is definitely positioned well and working, otherwise I wouldn't have been able to cycle up to 35km/h. But something with the coil positioning is really sensitive. Wonder if having a factory electromagnet (like the one suggested; 5v Electromagnet) with smaller diameter would result in less sensitive placement, as this coils outer diameter is 35mm covering a large part of the range. I think it is worth the try.

@megabobra, do I need to keep the resistors in place? Or can I also just remove the resistors and use a smaller electromagnet? See options: ee table: AliExpress electromagnet. Estimating from the eplus.bike manual, the magnet is quite small. View attachment 122859

View attachment 122855 View attachment 122856 View attachment 122857

Sorry to hear about your trouble. re the GPS in the app, on Android, you can grant the app location access, but keep GPS disabled. This allows you to run the ride screen without GPS on.
Does that mean though that when you rode for 1km and hit 35kph that GPS was on? If so, this would cause the error due to the bike/GPS speed mismatch.

Yes you can certainly try a different electromagnet coil. You don't have to have the resistors, they're in place to give ~15ohms total coil resistance as this was found to go generate a magnetic field of proportionate strength to the rim magnet. I originally used the 5v coil you linked with success, before winding my own to suit reduce its footprint. The aliexpress one you found looks the same, just make sure you select the 5v model, and take care that it's not too deep/tall to fit in position once the motor is back in then frame.

With the coil mounted in the location where it was running for 5min in setup mode, removing the setup mode plug, does the spinning the rear wheel then show speed correctly?

I think before trying a different coil, you should persevere with this setup. Finding the correct coil location is definitely tricky, but if you're running a constant speed for 5min in setup mode, that's the right spot. I'm really wondering if its GPS related... Why don't you try a ride without GPS turned on at all? Or otherwise, with bluetooth turned off (so that you're definitely disconnected from the bike) and then use google maps (sorry, or apple equivalent?) to show the GPS speed to check you're hitting 35kph under power?
 

littleleye

New Member
Jun 25, 2023
11
4
the Netherlands
Sorry to hear about your trouble. re the GPS in the app, on Android, you can grant the app location access, but keep GPS disabled. This allows you to run the ride screen without GPS on.
Does that mean though that when you rode for 1km and hit 35kph that GPS was on? If so, this would cause the error due to the bike/GPS speed mismatch.

Yes you can certainly try a different electromagnet coil. You don't have to have the resistors, they're in place to give ~15ohms total coil resistance as this was found to go generate a magnetic field of proportionate strength to the rim magnet. I originally used the 5v coil you linked with success, before winding my own to suit reduce its footprint. The aliexpress one you found looks the same, just make sure you select the 5v model, and take care that it's not too deep/tall to fit in position once the motor is back in then frame.

With the coil mounted in the location where it was running for 5min in setup mode, removing the setup mode plug, does the spinning the rear wheel then show speed correctly?

I think before trying a different coil, you should persevere with this setup. Finding the correct coil location is definitely tricky, but if you're running a constant speed for 5min in setup mode, that's the right spot. I'm really wondering if its GPS related... Why don't you try a ride without GPS turned on at all? Or otherwise, with bluetooth turned off (so that you're definitely disconnected from the bike) and then use google maps (sorry, or apple equivalent?) to show the GPS speed to check you're hitting 35kph under power?
Thanks again for the reply!

Unfortunately, I cannot disable location independent of apps on Apple.
When out of setup mode I tried turning my wheel which does provide a speed constantly (whether it is accurate is hard to determine).
Of course when riding my bike I powered down my entire phone to avoid any connection with GPS. The speed was measured with my exercise watch with GPS.
Still I get the speed sensor error, despite it was in the exact location it was running for 5min in setup mode. I don’t suspect it is due to cycling with the bike, but due to slight movement of the coil and cables while assembling the motor into the frame again. Hence looking for an option with less sensitive coil placement. Going to give the factory elektromagnet a try.
Will update in a few weeks, once I have received everything.
 

AlumiPro

Active member
May 1, 2023
168
107
California
Just to check something .......

There's a mix of things there .. Gen4 - would be correct if it was the Bosch Gen4. (gen4 motor)

Levo - would be gen3 (Third generation of Levo) if it was a new one and Brose 2.1/2.2 motor would be correct for the motor.

The megabobra system is designed to work with the Bosch Gen4 Smart System - so if you want something for a Levo you need something like a planet 3 or a levociraptor.
I corrected, I meant Gen3 Levo. I’m not putting this system on that bike. I was just explaining how the speed sensor wire is installed on it….thinking maybe I could do the same with the Megabobra reed sensor and magnet
 

megabobra

Active member
Jul 24, 2022
229
253
Australia
Anyone else had a change to install their megabobra yet? I'm obviously hoping you have more luck than littleleye!
 

bail0ut

New Member
Jul 31, 2023
7
9
UK
Anyone else had a change to install their megabobra yet? I'm obviously hoping you have more luck than littleleye!
I’m doing mine today but unsure if the LPP is enabled. Asked in two dealers if they would check with the Bosch Diagnostic Tool, both refused because I didn’t buy the bike from them! I guess the only way to find out is to rough in the megabobra and see how it goes…
 

bail0ut

New Member
Jul 31, 2023
7
9
UK
I’m doing mine today but unsure if the LPP is enabled. Asked in two dealers if they would check with the Bosch Diagnostic Tool, both refused because I didn’t buy the bike from them! I guess the only way to find out is to rough in the megabobra and see how it goes…
Seems like the LPP is disabled as I’m unable to get a speed reading on the kiox when holding the coil in place, just stays at 0 no matter where I place it.
Time to try find a friendly dealer.
 

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