Interactive mini exersice bike games

Hi, I’m looking to make interactive excise game in which a min excise bike is connected to computer (through USB or BT).
Speed and/or torque from bike is to be used a speed control for a computer game and the game set the resistance of the bike, so that when going uphill resistance is high and when going downhill resistance is low.
The speed feeback from bike to computer seems easy, to control resistance from computer seems more tricky, one option considered is to use a motor from electric bike or scooter as generator and some variable resistance as load that can be controlled from computer interface.

Hi Nathan,

thats very easy for an electrical engineer.
You can use a brushed DC-Motor, a voltage controlled current sink and a D/A converter,
if you want to burn the Energy in a transistor.

You can also use PWM and a transistor to shot-circuit the DC motor, but then of you open it again,
you get very high voltage spikes that you need to neutralize some how.

I would suggest building a step-up DC/DC-Converter and charging a car-battery or the like from
the movement. You can change the current for charging by influencing the feedback loop in the
PWM circuit.
To get a feeling about such circuits look at old UC3845 datasheet. Here you see an error-amplifier
that compares the feedback voltage with a reference voltage to cut the width of ramp pulses

at a certain level giving you pwm.

So you can influence the reference voltage or just take a resistor and add an “error signal” on the feedback
line using a simple D/A converter.
So the DC-DC-Converter will up-convert more or less.

How is the situation about covid-19 in Israel what about travel?

Have fun

Ludwig

One that I saw had a belt around the wheel that could provide friction, which was then pulled tighter or looser by a small DC gearmotor and a threaded rod.

If you don’t wish to build your own, you can buy a new (or better, find a discarded) exercise bike that already has an electronically controlled load.

You can also build a wheel hub Like the hub needed for gear shift.
There you put ground steel and an electric magnet. If you Energie the magnet the steel particles stick and produce friction. The friction is controlable using the strength of magnetic field which is controlled by coil current.

So you get a magnetic brake.

Have fun

Ludwig

Made progress, HowTo and code for first game availible on github: