Mmm, not really like a motorcycle, no.
The motorcycle doesn't integrate human power and electric assistance, which is all this does, motor-wise. In fact (though I don't think I put this in the first post), with this system, unless one were to defeat the code for it, it will only allow the motor to work while you are pedalling, because it's throttle control is how hard you are pedalling. Or rather, a threshold above which the motor runs, and the harder you pedal the faster it runs, so that it attempts to keep you from having to pedal harder than the user-configurable amount of force. That's partly so that if a rider (like me) has bad knees or whatnot, it can be set to help keep pedaling force below the point of pain or injury, while still allowing higher gears for faster speeds.
Without the simple motor assist I have now, I'd maybe be able to go 7 or 8MPH, at most, and would have to get off and walk in a headwind. With the assist, I can easily maintain 15-20MPH and actually get where I'm going before the day is over. Unfortunately, what I have now is not very efficient, for a lot of reasons, and the batteries are also old and heavy (SLA), and are nearing the point where they will have to be replaced with *something*, pretty soon. See this post for some of the info and pics of the system I am using now: http://electricle.blogspot.com/2008/07/ ... creen.htmlhttp://electricle.blogspot.com/2008/06/ ... drive.html
Except for the integration of all the systems together, and the safety features it would have available as a result of the integration making monitoring of many things and feedback to each of them from other systems possible, this is pretty much like any other electric-assist kit for bikes that already exists (there are at least dozens, if not hundreds, of different types).
Most of them are cheap, and their prices reflect that. Some are pretty good, or even very good, and are generally significantly more expensive. This one would be in the upper end of the price range for kits; my guess is that it would cost (depending on battery type chosen to power it) upwards of $1500. Much less if only using SLA batteries to power it, but then it would weigh a LOT and have little range.
Now, many of the other kits out there are capable of just driving the whole bike without any pedalling, and depending on the motor used with this kit, that's possible with it, too, power-wise. But I don't want to have a separate throttle on this one, simply because, well, I don't want to.
There are actually more reasons for that, but the biggest ones boil down to that. I don't want one more thing to put on the handlebars. One more thing to distract from riding or have to do with my hands. One more thing to break in a crash or if the bike falls over on it's side and the bars hit the wall or the ground (common occurence when I'm at a store, because people mess with stuff and/or they aren't careful when locking up or removing their own bikes from the common rack). WIthout the separate throttle, one must at least pedal minimally, even though the force can be set really low on the config page.
One catch: I don't know what kind of sensor would be best to use for this. It can't be a simple magnetic or optical sensor, because those will only detect speed, and that's irrelevant. Pedalling *faster* doesn't make the unit iincrease motor speed, it only pedalling *harder*. Strain gauges of various types are probably necessary, but all the ones I have seen are going to require placement on the pedals themselves (so they detect the pressure of the foot on them) or on the cranks (so they detect torque forces at work across the length or width of the crank), and both of those are moving all the time in relation to the bike, and thus must have a sensor unit that contains it's own power source, as well as a way to transmit the information to the rest of the bike.
Electrical contacts such as rings with tabs or fingers rubbing on them to maintain connection are not going to work in the very dirty environment of a typical bottom bracket. There also is little space there on most bikes, so finding a place to put the contactor rings and fingers is a little difficult.
For the recycled-parts recumbent I'm building that will have a similar (but analog-based) throttle system, the communication will be done with an IRLED from each pedal unit, inside the Bottom Bracket housing, actually mounted on the crankshaft between the bearing rings. The wire will be run from a box on the back of each pedal that will contain the batteries and electronics for the sensors, via a groove in the shaft under the threaded rings and bearing cups, etc, to the center of the shaft. An IR receiver and preamp inside the BB will pick up the signal (which is being reflected around the inside of the BB housing, meaning the signal gets stronger and weaker during rotation but never interrupted), and amplify it and pass it along as a throttle voltage to the analog-based motor controller I've already got.
The actual sensor to translate the pedalling force into voltage to transmit to the IRLEDs hasn't been decided yet, since I don't yet know enough about the different types. It has to be something that either is already weatherproof or will still work fine once it is encased in weatherproofing.
Piezo elements might work, since they generate a voltage when distorted, and that distortion can be forced to happen depending on how they're mounted on the pedals and/or cranks.
Resistive strain gauges might work on the cranks, detecting the flex of the cranks. Since every kind of them (and there are a LOT) is different, and would flex differently, there must also be a calibration routine on the controller that the rider can run while stationary to configure the min and max flex levels detected. The same is probably true of any sensor used for the throttle.
Again, I really don't know how to do this part yet, just have a number of possible ideas for it.
This is going to be the very first hurdle to overcome, of many.
I expect the programming will be fairly easy for anyone that knows how to do it, but will almost certainly be pretty large. FWIW, I was originally going to just use the STM32Circle device for the actual bike computer, before I gave up on learning to program in C (I really really just can't remember enough of it as I go along to get anywhere). I don't recall the exact MCU that's in it, but the MEMS 3-axis accelerometer in it is really what got my attention, because it can be used as a mouse pointer to move the cursor around it's screen (it comes with PacMan and Breakout clones on it, to showcase that ability). Naturally, it can also simply be used to detect bike tilt, acceleration, deceleration, etc, to monitor each of these and engage safety and other features based on those factors. It also has it's own realtime OS on it, which is a big factor in making me want to use it, since it makes a lot of things easier to do. The color LCD screen was also a feature I could see a lot of use for, primarily as speedometer and battery condition display.
The bike computer itself I would like to have be removable, with a USB port to hook to the computer to power it and charge it's backup batteries (it would be powered by the main bike batteries normally), and to both reprogram the computer with firmware updates and to do the configuration on the PC (Windows or Mac or Linux system, if possible). Using the MEMS sensor, on-the-road config is also possible, though much more tedious, by taking it off the bike and entering config mode, then using the tilt to move the cursor around, etc.
The reason for that design was that the STM32Circle only has one button, and the MEMS sensor, for input. If the bike computer box is designed from scratch rather than using the STM32Circle, a separate cursor pad can be created and used. That would add to the complexity both of building it and of weatherproofing it, but would certainly make it easier for the rider to do on-bike setup.
I'm not set on using any specific MCU, so whatever you (or others) have experience with that can do the jobs needed here is fine. I don't know exactly how many of which kinds of I/O it's going to need, but I have a feeling it will need to be a fast one with a lot of program EEPROM and user-flash available. Since I already have an STM32Circle (and another USB-based STM 8-bit MCU) development unit, I could at least test things on my end if that's used--otherwise it could be a while before I could afford whatever dev kit or stuff is needed to do this with a different MCU (I got the STM stuff free at a distributor seminar).
Enough for now, before I bore you.