adding a pedal sensor to my trike controller?

[lucajo16]

Hi everyone! After a ton of thought I have decided to convert my trike over with this kit here.
https://www.amazon.com/WPHMOTO-Cont...ic+trike+kit&qid=1551040612&s=gateway&sr=8-15
Problem is that it doesn't have a connection for pedal sensor.....and I don't want the extra wires of the throttle going from my handle bars to my basket in the back of my trike. also I plan to run this battery here.
https://hobbyking.com/en_us/turnigy...9-tdR16A81ppEHLEBIvv2Y2oC7uEeNWEsvAfHodEwgckk
Now I am sure the battery will be more then enough for the motor but my problem is the pedal sensor for the trike. I have never really worked with a controller like this so I'm hoping I can add a pedal sensor to this kit. I am looking for a stealthy build for my job
because my job disapproves of workers using ebikes for the job and I know if I build it right they will never notice. any tips would be
great! this will be my 2nd ebike ive built and cant wait to build this one!

 

[amberwolf]

There's no direct way to add PAS to that controller.

You can design and build a circuit that takes PAS pulses from a common multi-magnet-ring PAS sensor and converts them to a voltage that is within whatever the range that controller takes as throttle input. It's not terribly complex, but if you have no electronics knowledge it might be an interesting learning experience. It is pretty cheap to make, though--the most expensive part would be the PAS sensor itself, and potentially the soldering iron, solder, and other tools you'd need if you don't have them already.

Basically you'd use something like a 555 timer chip in a retriggerable one-shot circuit, so it basically just shapes the pulses coming from the PAS sensor. If the pulses come in fast enough it'll keep extending the pulse from the 555. Then the 555 feeds into an integrating op-amp circuit, that converts the pulse length into a voltage. Longer pulses mean higher voltage, so the faster you pedal the higher the voltage, and thus the more throttle is applied to the controller.

If you didn't have a really low budget, I'd recommend the Cycle Analyst v3, which can take most PAS signals and convert them to a throttle signal. It can be mounted with the controller, doesn't have to be on the handlebars. But it isn't cheap--generally costs more by itself than the kit you linked above. :/


If you don't want a visible throttle on the bars, and can't put a PAS on there, you could just put a button on the bars that turns the trhottle input on and off. Primitive and harder to control exact speed/etc with, but at low power-to-weight ratios it works ok.


Alternately, you could use an actual throttle, but not put it on the handlebars. Instead, take a grip shifter or lever shifter, cable operated, and take the ball bearing out of the grip shifter (or set the lever to friction, and loosen up the tension screw). Then run the cable from the shifter back to the actual throttle wherever the controller is. Youc an use an actual throtle and build a mechanism to create leverage for the cable to turn it, or you can buy one of the flat pulley-operated throttle units (I forget where, but a recent-ish thread ahd a picture of and link to one).

 

[lucajo16]

what about just changing out the controller to one with a PAS system? is that possible?

 

[amberwolf]

While there might be PAS controllers for brushed motors, I haven't seen one myself.

A quick google finds discussion about it, but when I looked at the first handful of links I didn't see one that actually supported PAS. Might be one there though, or under other search terms.

https://www.google.com/search?newwindow=1&ei=Mpp1XNarMueS0gKjpq6ICw&q=PAS+controllers+for+brushed+motors&oq=PAS+controllers+for+brushed+motors&gs_l=psy-ab.3...2617.2617..3484...0.0..0.169.169.0j1......0....1..gws-wiz.5upkdQrmOb8