Hi guys,
Im another total beginer, to electronics as well as Arduino. I've scoured this forum, and the net in general - but wondered if anyone could steer me in the right direction for something I'm doing.
For a project I'm working on, I want to be able to monitor the speed a user is cycling on an exercise bike. Ideally, I'd be able to detect the whole range, from incredibly slow to incredibly fast - and use the data accordingly. Also, in an ideal world, I'd like to be able to see if the user is pedaling backwards.
I've read that Rotary Encoders may be the best way to do this, but have also been advised to try dynamos, hall effect sensors and some other things.
I've got my code all up and working with a potentiometer - so hopefully if I get the right input device, i can just update a few llines to make it work on speed instead of potentiometer rotation.
Any suggestions would be really helpful.
Cheers.
CF.
Thanks for the quick response!
I was reading the wiki entry on Hall Effect sensors - would they be able to detect very slow speeds on the bike - I'd like it to be very accurate and responsive at the slow end if at all possible. Does a hall effect only send out a reading once per revolution of the wheel?
All I meant about my code is that I've got my app pretty much finished and just need to find a nice way of inputting my data through whatever input device I get. So I'd just replace my rotation variable mapped from the pot, to the speed variable I'll calculate from whatever sensor I end up with. Hopefully! ;D
If you use the hall sensor (and there's loads of code around this forum to give you RPMs), but you absolutely want the direction of rotation, then you will need 2 sensors. The sensor that triggers first gives you the direction of motion.
Thanks for your advice too Richard.
I'm glad I came here before I placed an order!
The Optical RPM Sensor sounds really promising - I'll do some reading up on it.
Sorry to disappoint you Paul, it's just a vague Simpsons reference -
Bart After Dark [8.05]
Marge: Now the cat needs his medication--
Homer: No problem.
Marge: --every morning and the furnace--
Homer: Can do.
Marge: --has been putting off--
Homer: Right.
Marge: --a lot of carbon monoxide--
Homer: Uh-huh.
Marge: --so keep the window open.
Homer: Gotcha - cat in the furnace!
Marge: Hmm, you know, I think I'll take Maggie with us. And if anything happens, just use your best judgm... mmm... just do what I would do.
If it uses a spoked wheel like a regular bicycle, you could get one of those bike speedometers. Sometimes you can find them real cheap, and maybe even cheaper if you can just buy a "replacement sensor" for one. The "sensor" is just a hall-effect sensor and a magnet which mounts on a wheel spoke. This would come with mounting hardware and the sensor already soldered to wires and inside a molded casing. Just a thought.
