You could "cheat" the thun being used as a pedelec control by jumping up and down on the bike
I love it
Indeed, in my first playing around with a THUN unit earlier in the year I was only using one of the two pulses from the cadence encoder, and there was literally no way to prevent pedalec mode from kicking in if you are standing on the pedals left foot forwards. Any slight rocking back and forth looks to the system like you are pedaling with massive force. Proper use of quadrature input solve that
It was also neat to see how much negative torque is applied across the spindle in the course of routine pedaling, where the action of the right leg pressing down does the work of lifting up your left leg. I suppose it's more efficient use of leg muscles to push down rather than to lift up? Interestingly you wouldn't see any of this left<->right pedal play with a strain sensor on the chainring. So even though that would properly show the net power of both legs getting to the wheel, it doesn't show the percentage of torque from one leg that is being absorbed by the other leg rather than being transmitted to the chain.
Anyways, I did hear back from THUN and they're pretty interested to see an ebike display and interface compatible with their sensor, and seem keen to help us make that happen. The pricing is reasonable enough that we'll probably stock them by Jan/Feb of next year and be able to offer a THUN + CA bundle in the $330-$350 price range. I suppose it's a bargain compared to existing bicycle power meters (mostly >$1000 as has been mentioned here), though may seem a bit pricey if all you want is to add pedalec functionality and don't care so much about seeing human wattage.
There are 5 different spindle lengths to choose from with the THUN BB, anybody have an idea on the distribution of spindle lengths in ebike usage?? I've never had consider this question before.
BTW, a quick google for the Thun sensor itself foudn this tidbit:http://www.aliexpress.com/fm-store/6055
whcih appears to be controller, pedalec sensor and Thun sensor all in one package for only $160 for 5 sets. Buuut...given the way things usually work out, it probably does not include anything but the controllers.
That's correct, it's a china trader selling controllers only, the use of the THUN image and name is pretty inappropriate. It also looks (judging from the cable pinouts) like it probably is just using the THUN bottom bracket for cadence sensing, rather than for actual pedal torque.