Speed Sensor? Torque Sensor?

Speed Sensor with less cost? Or spend more money for Torque Sensor?

  • Speed Sensor is enough for me

  • Torque Sensor is everything!


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Woosh

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VictoryV

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Feb 15, 2012
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it's just a programming task.
This paper shows how to calculate speed and distance using gyro data:

https://www.nxp.com/docs/en/application-note/AN3397.pdf

From the speed and gradient (you get it from the same I2C bus), you calculate the required power.
In the aircraft world and other applications such as submarines, space flight, and artillery positioning it is called "inertial navigation" and has been in use in one form or other since the 1960's. In those days the hardware was just a little bigger - the 1970's gyro for the Jaguar aircraft was a 2 man lift into the airframe!
 
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Woosh

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the 1970's gyro for the Jaguar aircraft was a 2 man lift into the airframe!
how time has changed!
The new chip measures 4mm x 4mm x 1mm.

 

Wisper Bikes

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.....or we could could use a tried and tested torque sensor that sits in the BB and is operated by pressure applied to the cranks through pedals. It's not only in hills that we need more power it's for acceleration too. A torque sensor is simple and effective. I understand it's not perfect for everyone hence the reason the twist throttle overrides the TS and we have a cadence sensor only mode on our Torque models.
 
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VictoryV

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how time has changed!
and the operational computer memory was "core store" with a capacity of 6Kb - it was wired by specially skilled ladies who could thread the copper wire through the ferrite cores by hand. It also weighed about 40 lbs when fully cased and ready for installation. To do diagnostics we had to unload the flight program and reload the diagnostic program with a 1" mylar tape that had been perforated for the code and optically read. The reader/loader was in its own servicing trolley with a 28v aircraft battery to provide for use on the flight line without mains electricity - we used to tow it with a landrover!
 

Woosh

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VictoryV, you make me feel so old!
 
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Woosh

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Are you saying that it can directly sense the force that the user is applying to the pedals? If so, how does it do that?
No, they don't need to. With the gyro, they can do one step better than cadence sensing. They can work out the average ratio user input power / motor power without needing a torque sensor.
 

chris_n

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No, they don't need to. With the gyro, they can do one step better than cadence sensing. They can work out the average ratio user input power / motor power without needing a torque sensor.
I don't think the gyro can predict when you need a little more power to lift the front wheel over an obstacle in quite the same way that a torque sensor is going to respond to your input.
 
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Woosh

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I don't think the gyro can predict when you need a little more power to lift the front wheel over an obstacle in quite the same way that a torque sensor is going to respond to your input.
that's when the inclinometer comes in handy. Both are built into the same chip.
 

chris_n

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I'm talking about a pre-emptive increase, once you hit the obstacle maybe a branch on the trail it is to late to increase the torque because you are already over the bars! When I am riding off road particularly when it gets steep and narrow you need to be able to control what is going to happen, not what has already happened.
I'm not saying the other systems won't work for some but for me and some others on here they are not the answer.
 

Woosh

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I'm talking about a pre-emptive increase, once you hit the obstacle maybe a branch on the trail it is to late to increase the torque because you are already over the bars! When I am riding off road particularly when it gets steep and narrow you need to be able to control what is going to happen, not what has already happened.
I'm not saying the other systems won't work for some but for me and some others on here they are not the answer.
you do have a point. The gyro system won't suit everyone's requirements but on this, all systems have their critics. That's why earlier in this thread, I suggested that the torque sensor system should also have switchable a throttle. The old BH Neo and Evo bikes had this implementation. The gyro is the way of the future because it has less wiring and intrinsically cheaper to implement.
 

2Lazy

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Jul 17, 2013
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On the original question from the OP.

On my ebike that I use for commuting I have a cadence sensor. I much prefer this, for commuting, as I want full power with minimal effort. Effectively I want an electric scooter - it just happens to be bike shaped and has pedals.

My e-MTB on the other hand is a Haibike with Yamaha motor. I prefer this for off road use and for leisure use when I want to get some exercise.

For me the cadence sensor vs torque sensor question really depends on the individual use case and personal preference.
 

anotherkiwi

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Yesterday I saw my first ever throttle in use on a pedelec! A young lad walking his dog (not on leash, on the footpath... ) in San Sebastian. No effort to move the pedals whatsoever just your average electric scooter. A 285€ combined fine just waiting for a policeman to happen! :)
 

Woosh

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I learned something new today.
A potential supplier mentioned their 'Inertial cruise system'.

Above a set speed, if the user stops pedaling, the bike will maintain its current speed until the user decides to brake or start pedaling again.

What do you think of it?
 
D

Deleted member 4366

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To be compliant with EN 15194, the power has to stop when you stop pedalling.

I've used cruise control on some bikes, but I never really felt comfortable with it. I guess you'd get used to it, but I always found it a bit disconcerting when it engaged when I didn't want it.

On the surface and without trying it, I'd say it's one of those ideas that sounds good in theory, but has little practical use other than to save you the cost of a throttle, and only then if there were an on/off button to switch it off when you didn't want it active.
 

anotherkiwi

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I'll skip cruise control and wait for autopilot :rolleyes: