I want my BBSHD Speed Sensor Disabled

[davidsng]

Hello, I see on my SPEEED App for bbshd, there is a some sort of "External Speed Sensor" by pass.

The options are by "internal meter" and "motor phase". Here is a screen shot. I found nothing on it anywhere.

Does any one know how to bypass the external steed sensor?

I have a bike only designed for off-road. I'm sick of damaging my speed sensor over and over.

 

[davidsng]

Hello, I've been looking on the internet for many days now, but can't find and answer. So, I joined this site.

Has anyone learned how to disable the Bafang BBSHD External Speed Sensor?

Reason for this is I'm building a bike dirt bike and don't want to keep damaging my speed sensor near my rear wheel.

I found on the Bafang SPEEED App, this setting.

Motor Speed has three settings. 1. External Sensor, 2. Internal motor meter 3. Motor Phase.

Has any one successfully accomplished this?

I want some feedback before I try it.

 

[amberwolf]

Hello, I see on my SPEEED App for bbshd, there is a some sort of "External Speed Sensor" by pass.

The options are by "internal meter" and "motor phase". Here is a screen shot. I found nothing on it anywhere.

Does any one know how to bypass the external steed sensor?

I have a bike only designed for off-road. I'm sick of damaging my speed sensor over and over.

The motor phase sensor just reads the motor speed. It will only work while the motor is spinning, and unless you have a singlespeed system that cannot shift gears, it can't tell you the actual wheelspeed because it doens't have any way to know what gearing ratio is between the motor and wheel at any moment.

To read the wheel speed, you have to have a sensor that actually reads the wheel speed, which really means having something like a magnet on the wheel, and a sensor on the frame.

There are almost certainly ways to setup such a sensor to be protected against damage, but without knowing what you've already tried and the kinds of damage already experienced, and the conditions it has to survive, it's hard to give specific suggestions.


There's been discussion about not using a speed sensor at all, but I don't recall any successful instances--IIRC the controller will timeout and shutdown if it doesn't detect motion after a certain amount of time.

You could build a small 555 timer chip (or other device) that just continuously outputs a stream of "speed" pulses to keep the controller awake, wired in place of the wheel speed sensor, and installed wherever you find is safe from damage on the bike.

 

[E-HP]

Does any one know how to bypass the external steed sensor?

So by bypass, do you mean that you don't need to monitor your speed, or are you looking for an alternate way of monitoring it? Would a speed sensor on the front wheel also be problematic?

 

[davidsng]

Thanks for the answer. There has been talk about this topic, but nothing is concrete. I'm building a single speed bike and just want to run the motor without any type of speed readings. If I had only an RPM reading that would be great! I want the least amount complexity as possible, and the most durable bike possible.

I heard from some I has been done with an Bafang Ultra motor with an internal magnet on the drive staft and after market controller. Then you can program the MPH on 100 rpm of the motor, or something like that.

Ill be testing this Intenal sensor and phase sensor speed out on my other bafang bike soon, im just hoping not mess anything up. That is why I want to post this before trying it.

 

[davidsng]

So by bypass, do you mean that you don't need to monitor your speed, or are you looking for an alternate way of monitoring it? Would a speed sensor on the front wheel also be problematic?

Thanks for the reply. I clarify my reasoning.

I broke my speed sensor twice in one year, off riding with my standard bbshd set up. It is really annoying to have it keep breaking during off road trips. That is why I trying to make an indestructible off-road ebike, for long outings and rugged terrain. Those dinky speed sensor don't work for that.

 

[davidsng]

You could build a small 555 timer chip (or other device) that just continuously outputs a stream of "speed" pulses to keep the controller awake, wired in place of the wheel speed sensor, and installed wherever you find is safe from damage on the bike.

This look promising. I thought of this before but I did not know what device would work on it.

How would I pick one out? How would I wire it in? Cut the speed sensor cable, wire it in? Is it that easy? I would need one with at least a few seconds interval, or slower? Wouldn't a fast one would make the bike shut down if it makes the bike register 100mph?

 

[amberwolf]

How many pulses per second does your speed sensor show, on average, when you're riding the way you usually do?

That's how many pulses per second you would build the timer circuit to create.

There are a number of websites with various 555 timer circuits,

555 timer circuits - Google Search

including the calculators for what resistor and capacitor to use. You want the "Astable mode" that creates a simple "clock" signal, or pulsetrain. It's easy to work out, setup, and build, if you have any electronics experience, and not too hard to learn if you don't.

555 Timer Operating Modes

www.555-timer-circuits.com

The 555 probably can't run directly off your battery voltage, but it can run off 5v, so if your speed sensor has 5v, signal, and ground going to it, you can power the timer from the 5v and ground, and connect the signal to the timer's open-collector output on pin 7. (rather than the one on pin 3, which may or may not have the right output swing to run your controller's speed input).

The controller probably already has a pullup resistor from signal to 5v internally. If it does, then the timer will just "work" to provide a speed signal. If it doesn't seem to work reliably, you may need to add a pullup resistor (5kohm to 10kohm) from signal wire to 5v at the timer.

 

[davidsng]

Thank you so much for the start. I have been looking at those all day and have several picked out. I'll do some testing, research and post my results.