ChronoFish
- Oct 14, 2010
- 3
- Joined
- Oct 14, 2010
- Messages
- 3
Hello, I'm looking for some suggestions:
I am a professional software developer, novice electronics hacker and experienced triathlete.
For the heck of it, this winter I would like to transform my mechanical resistance rollers (think treadmill for a bike) into computer controlled resistance rollers.
I've done enough electronics hacking that I can use a PIC to drive 7-segment displays and communicate status through a parallel or serial port. But that is about my limit.
Here's my (non-unique) idea:
I would like to hook up one of the rollers to a motor. The motor would be capable of spinning the roller (backwards) with a power output of 0 up to 1 HP (745 watts). The step increase is TBD - probably between 0.5 and 1 HP. This is a safe upper bound that I am not, even for a short period time, going to exceed.
Without knowing much about a given motor, how can I measure the output (or input) of the motor?
Do I have to do it via calibration and use of a lookup table, or can I determine this on the fly? And if calibration is the way to go - how do I do that?
Is it better (easier) to control the power to the motor via mechanical means (like a servo turning a rotary resistor) or to use some sort of PWM scheme?
The motors I have available are things like a 2HP AC circular saw motor and a DC motor from a batter powered weed-whacker (unknown power rating).
Are the power outputs of motors different when the motor isn't actually spinning (i.e. braked) - or spinning backwards?
In other words as I pedal my bike the motor is actually acting as a break trying to spin the roller in the opposite direction.
Thanks for your suggestions.
-CF
I am a professional software developer, novice electronics hacker and experienced triathlete.
For the heck of it, this winter I would like to transform my mechanical resistance rollers (think treadmill for a bike) into computer controlled resistance rollers.
I've done enough electronics hacking that I can use a PIC to drive 7-segment displays and communicate status through a parallel or serial port. But that is about my limit.
Here's my (non-unique) idea:
I would like to hook up one of the rollers to a motor. The motor would be capable of spinning the roller (backwards) with a power output of 0 up to 1 HP (745 watts). The step increase is TBD - probably between 0.5 and 1 HP. This is a safe upper bound that I am not, even for a short period time, going to exceed.
Without knowing much about a given motor, how can I measure the output (or input) of the motor?
Do I have to do it via calibration and use of a lookup table, or can I determine this on the fly? And if calibration is the way to go - how do I do that?
Is it better (easier) to control the power to the motor via mechanical means (like a servo turning a rotary resistor) or to use some sort of PWM scheme?
The motors I have available are things like a 2HP AC circular saw motor and a DC motor from a batter powered weed-whacker (unknown power rating).
Are the power outputs of motors different when the motor isn't actually spinning (i.e. braked) - or spinning backwards?
In other words as I pedal my bike the motor is actually acting as a break trying to spin the roller in the opposite direction.
Thanks for your suggestions.
-CF