Generating power from a stroller

[Ezzie_g]

Hi, I am looking to add to my stroller a generator that will generate power to run a series of lights the i will place on the frame at different points. for your referance i want to build this on a "bob revolution se dualie stroller"

The point of the lights is nothing more than visibility and will most probably be mini LED style flashlight heads with color filters (red for the back and white for the front). I want to generate power for the lights by moving the stroller and the big issue that I am having is how to determine not how much power I need to generate but how to measure how much power I can generate by spinning the wheel.

The wheels are independent and do not have an axle as such I will need an induction motor where the axle is connected to small wheel that is in contact with the stroller wheel itself. the stroller wheel has a radius of 8 inches. And I want to power 4 points (each running their own wires motor to lantern). the flashlights for the sake of argument) will be of the costco (inexpensive non specialty) variety where 3 or 4 AA batteries power 5-10 LED bulbs. the design is simple enough. my only issue is identifying which motor to buy as the axle won't be spinning very fast and i need to generate power.

can using a small point of contact between the axle and the stroller wheel I can turn the turn the axle at a higher speed generating more power?

also where is a good online source for motors that small?

 

[NascentOxygen]

I want to power 4 points (each running their own wires motor to lantern).

Hi Ezzie_g, http://img96.imageshack.us/img96/5725/red5e5etimes5e5e45e5e25.gif

An interesting idea you have here. You do realize that having the wheels generate power will make the stroller much harder to move, particularly at speed. This could in some circumstances prove an endangerment, this hinderance to rapid evasive movement.

This aside, I suggest that you harness just two wheels, and gauge whether your idea is going to be practicable on that basis, anyway. I can recall how the bicycle dynamo rubbing on the edge of the tyre made pedalling considerably more difficult. That friction drive itself is lossy, even when no electrical power is drawn.

Alas, I can't help with information on available hardware. You'd be looking for a permanent magnet generator.

I presume you are out and about during low light conditions, otherwise I would suggest solar cells as the way to go. They may still be an option if you can park the stroller in bright sunlight for part of the day.

Good luck with your project.

 

[sophiecentaur]

As already stated, you don't get anything for nothing and you need to provide several extra Watts of 'push power' to get the hundred or so mA at 4.5V for each LED. Bicycle dynamos are really inefficient when they rely on a jockey wheel rubbing against the tyre. The best ones work with magnets around the hub and pickup coils on the bike frame. One problem with a stroller is that the wheels are very small and a 'hub dynamo' style would be situated very low and susceptible to the wet and damage. I guess the magnets could be incorporated within a solid, moulded tyre, and a 'caliper style' pole piece could be arranged to sit over the top of the wheel. You need a very small gap, though and that could be a problem. You would also pick up all sorts of magnetic rubbish material off the pavement, like nails and tin cans, which could get caught in the gap.

Unfortunately for you, if only there were a single axle across the non-steered pair of wheels then the dynamo could be fitted in an enclosed 'pod' with very little stray magnetic field. There is, in fact, an advantage in having small diameter wheels in that the rotation speed is high (but the lights go out when you stop, of course).

LED lighting is a very low load, though, and three AAA batteries will last you a very long time. You can buy just what you need from a bicycle shop. For effective visibility in traffic, high vis tape on you and the stroller is good value - it's someone else's electricity.

 

[256bits]

What about some type of a derivative of those shaker LED flashlights that they sell? You could somehow test one to see if the stroller has enough 'bumpiness' somewhere on the frame to keep a shaker flashlight charged and able to light some LED's.
Or hook up some kind of crank from the wheel to the shaker.
If that works then you could remove the LED's from the head and position them around the stroller as you wish, being connected to the shaker with some insulated wire.

Even when you are stopped the shaker flashlight

 

[NascentOxygen]

I want to generate power for the lights by moving the stroller

If you include hefty storage cells so lighting can be maintained while stationary, then on approaching a steep incline you could throw a polarity reversing switch and have the four generators operate as motors to assist with the hill climb.