Bike Generator - Kit Recommendation

New to forum and Arduino circuits. Basically, I've not much electronics experience at this level, but have the capacity to learn :o . I work for a school district and hope to pick up a teacher or two with more electronics background, but until then I'm hoping for some advice on a bike-powered project.

I've a stationary bike-powered generator that puts out anywhere from 12 to 48 volts DC, depending on how fast the rider pedals. With middle school students, they produce around a steady 24-30 volts. It has a rectifier and we do okay with powering strings of LEDs connected directly, so long as the strings are long enough to absorb the voltage. We would like to develop greater applications, including a circuit-building kit that is powered by the bike generator. We do have a power converter that has a bank of capacitors and a transformer to produce AC voltage, but wanted to see if we could use the DC power directly off the bike somehow. Here are some specific questions:

1) What Arduino kit would be a good place to start that would allow students to develop 4 or 5 different circuit projects (e.g., lighting LEDs, running a fan, etc.).

2) What "regulator" mechanism would be needed to control the voltage output and provide steady power to the Arduino board without burning it up. I know I could simply attach batteries to absorb the voltage, but wanted to see if we could do it without batteries or capacitors. Maybe that's just not feasible.

3) Any suggestions on projects that use the Arduino system and the bike generator?

Thanks in advance for any help. Rusty

1) What Arduino kit would be a good place to start that would allow students to develop 4 or 5 different circuit projects (e.g., lighting LEDs, running a fan, etc.).

Any one would be suitable, with the proper voltage (5V or 3.3V, depending on model). Noe are suitable for powering from 24 to 30 volts.

2) What "regulator" mechanism would be needed to control the voltage output and provide steady power to the Arduino board without burning it up. I know I could simply attach batteries to absorb the voltage, but wanted to see if we could do it without batteries or capacitors. Maybe that's just not feasible.

Batteries or capacitors are needed to keep the voltage somewhat steady as pedaling cadence changes.

3) Any suggestions on projects that use the Arduino system and the bike generator?

What age students? What interests them?

AticusFinch:
2) What “regulator” mechanism would be needed to control the voltage output and provide steady power to the Arduino board without burning it up. I know I could simply attach batteries to absorb the voltage, but wanted to see if we could do it without batteries or capacitors. Maybe that’s just not feasible.

You are looking for a “switchmode” regulator specified for that voltage range.

What you have not discussed, is the power your generator develops at these voltages. Arguably it should be in the order of 100 Watts. the problem is that your power output is highly variable according to effort. You may have a fixed resistive load which will dissipate whatever power is fed into it, but most appliances expect to operate at one specific power consumption, less than which they will not operate (correctly and usefully).

Batteries and capacitors are required to store power when it is available for use at a more steady or at least predictable rate. And they store power very differently in terms of voltage.

Of course one particularly novel way to display the power generated is the “totem pole” where successively higher lamps are cumulatively lit.

According to Wiki, ...

A healthy well-fed laborer over the course of an 8-hour work shift can sustain an average output of about 75 watts.

Hi, Have you tried directly connecting the generator to a 12V battery, like a car/motorcycle battery or a small gelcel battery like those used in emergency lighting etc? Available at HomeDepot etc..

That would give you a voltage that would not be expected to exceed 14.4 volts or so. This would work nicely with the Yourduino RoboRED (UNO Arduino compatible) that has a built-in 5V switch mode regulator that can supply up to 2 amps at 5V. See info HERE: You can get that also in a Kit like THIS: with many devices to experiment with.

You can then run significant 5V and 12V devices.

Then use a simple Power Fet (Field Effect Transistor) like THIS: to control brightness of 12 volt LED strings or other devices.

Later you could measure and display (on a LCD like THIS: ) The voltage and current (And therefor Power) a rider is putting out..

Let us know what you decide and how it goes..

DISCLAIMER: Mentioned stuff from my own shop... (which is what I know something about...)