Replacement for Sempu torque sensor

[VooteleAer]

Hey, as I managed to rip the cable on my Sempu torque sensor, I thought maybe there's a better product available for replacement?
I have standard threaded bottom bracket, and using Cycle Analyst for the throttle control.
On the other hand, I would very much get rid of the CA, as it's not doing very good job - I have some KT controller that fits the battery bracket base, but I still need some good torque sensor...

 

[marvin78]

eRider T13? Though the only reference for pairing it with 'a KT 500w controller and LCD08 display' comes from this forum.

I thought CA was miles ahead of those cheap KT controllers btw, but then again not really my project type, to expensive ( I like those cheap KT's more lol ).

 

[VooteleAer]

CA is fine except it requires cadence sensor to rotate before it activates the throttle. So there's always some delay between pedalling and motor assist.

 

[marvin78]

CA is fine except it requires cadence sensor to rotate before it activates the throttle. So there's always some delay between pedalling and motor assist.

That's why I think any proper 'bicycle' should come with a torque sensor, so you don't have this disconnect ( also, you can ditch the throttle and have an actual bike riding experience vs a moped experience ).

 

[stancecoke]

as it's not doing very good job

There are now several alternatives:
A Bafang system of sensor and controller.

A Lishui system of sensor and controller.

A JYTCon system of sensor and controller.

Open source firmware is available for the Lishui and the JYTCon, which you can use to set up everything to your requirements if you are not satisfied with the stock firmware.

Of course, there is the old Kunteng firmware project also, that allows you to attach the BB torquesensor to your Kunteng controller directly. But Kuntengs are outdated and the firmware project is not maintained any longer.

regards
stancecoke

 

[amberwolf]

CA is fine except it requires cadence sensor to rotate before it activates the throttle. So there's always some delay between pedalling and motor assist.

You'd have to check the grin site for which version does this (or the notes in each fw in the ca setup program), but there is a firmware with the ability to start up purely from the torque sensor.

The caveat is that this allows accidental triggering of the motor by pushing on the pedals--that was why the cadence sensor having to show rotation (intent to pedal) was originally required.


I still want to try the feature out on the SB Cruiser, but at present it still works fine wiht the cadence sensor, having turned down all the settings for that to startup as quickly as possible from start of pedal movement. (under certain circumstances I backpedal to let the chain slacken just a bit then quickly forward pedal before the chain tensions up and I have to be pushing without any assist).

 

[VooteleAer]

Years back I had an idea to build chain tension sensor -:the top part of the chain would run over two rollers and twist springed arm that would trigger a hall sensor. This way it would only measure real force sent to the cassette, not just the weight of my feet resting on the pedals, like Sempu does. Right now, with Sempu it would sometimes have random full throttle surges even when I wouldn't pedal hard. It dirves me nuts, but I haven't found the cause of this.

 

[stancecoke]

the top part of the chain would run over two rollers and twist springed arm that would trigger a hall sensor.

This was my very first approach to build a torque sensor, it worked somehow, but was noisy...

Right now, with Sempu it would sometimes have random full throttle surges

Which generation of Sempu do you use? The first one didn't measure the torque, but the bending of the BB shaft.

There is an overview about available torquesensors in the German Pedelecforum Wiki:

elektrotechnik:drehmomentsensoren [Wiki Pedelec-Forum]

www.pedelecforum.de

 

[VooteleAer]

Seems to be 3rd generation.