My friend and I saw power pedal generator online and was wanting to attach LEDs such that as the person pedals faster one by one an LED will start to light up. I'm not sure how to go about making this circuit. We want to build this to be able to show at STEM fairs and similar events to attract people and teach them more about STEM.

http://pedalpowergenerator.com/shop-pedal-power/belt-drive-bicycle-generator-systems/

[URL]http://pedalpowergenerator.com/wp-content/uploads/2019/05/ppg-B300_owners-manual.pdf[/URL]

 

How comfortable are you with electronics? Do you have a multimeter? Can you solder? Can you make your own PCB, be willing to buy a custom one or work with protoboard?

The LM3914 IC can be used to do what you ask. It is a monolithic solution to a circuit of multiple comparators. Read this link to see how this chip may be used.

 

How comfortable are you with electronics? Do you have a multimeter? Can you solder? Can you make your own PCB, be willing to buy a custom one or work with protoboard?

The LM3914 IC can be used to do what you ask. It is a monolithic solution to a circuit of multiple comparators. Read this link to see how this chip may be used.

To answer your questions, I have a multimeter, can solder, and would be willing to buy a custom PCB or use my breadboard, similar to the link picture. I've never made a PCB but wouldn't mind trying.

Thank you for the link, I just want to make sure, the LEDs would not light up at the same time. would a hand made generator similar to the one in this link https://www.instructables.com/id/Electric-Generator-Powering-LEDs/ work instead of pedals???

 

Thank you for the link, I just want to make sure, the LEDs would not light up at the same time. would a hand made generator similar to the one in this link https://www.instructables.com/id/Electric-Generator-Powering-LEDs/ work instead of pedals???

What do you mean, the LEDs would not light up at the same time?

This chip supports two methods of display. The dot display would light one LED depending on the voltage on its signal output. If the voltage is 1/2 of the maximum voltage then the middle LED would illuminate. In bar mode, in the same situation, 1/2 of the LEDs would illuminate. The remainder would be dark.

 

What do you mean, the LEDs would not light up at the same time?

This chip supports two methods of display. The dot display would light one LED depending on the voltage on its signal output. If the voltage is 1/2 of the maximum voltage then the middle LED would illuminate. In bar mode, in the same situation, 1/2 of the LEDs would illuminate. The remainder would be dark.

So the project is for a fair type event and the original idea was as a person pedals a bike generator, and pedals faster the more LEDs would light up. So if they are going slow, not all LEDs would light up, maybe just a few or just one. I just wanted to make sure this or something similar would happen with the configuration you provided. I believe it would, but again just wanted to make sure.

 

So the project is for a fair type event and the original idea was as a person pedals a bike generator, and pedals faster the more LEDs would light up. So if they are going slow, not all LEDs would light up, maybe just a few or just one. I just wanted to make sure this or something similar would happen with the configuration you provided. I believe it would, but again just wanted to make sure.

Yes, that would happen when the chip is wired in bar mode.

 

The faster you peddle the higher the voltage , so the easiest way is to buy one of these for $1....

It's used to show how full a lithium cell is , one lights up at 3V , two at 3.6V all four light at 4.2V ...you can tap onto the wires and put in bigger leds ... If the voltage is not convenient there are similar things for 12V car batteries

https://www.ebay.co.uk/itm/Lithium-...312584?hash=item23c19043c8:g:O8gAAOSw3GxdMJ6r

this one has 5 leds ...some have ten .. put "battery capacity indicator" in ebay search

 

The LM3914 would be more fun with 10 LEDs. A small PM motor with friction drive on rear wheel is all that is needed.
Might find something on net.
If we knew what country that you are in might have source recomendations.

 

I am in the United States.

Would there be a way to do this on a bigger scale, to make the line of lights at least as tall as an average bicycle? or with light bulbs maybe?
The project is for a fair, so I would like it to be a few feet tall rather than the size of a pencil.

 

Using the LM3914, replace the LEDs with the LEDs of optoisolators and have the transistor output of the optos drive FETs to switch lamps. That is one way to do it.

Similar to this, but just hook the LED to the LM3914 as the "normal" LEDs are.