kinetic energy HAND POWERED AM receiver

(see project site here)

design by Gabriella Levine, Emily Webster, Genevieve Hoffman

The concept for our Kinetic Energy project evolved from an interest in generating sound by hand. What we ended up creating was an AM frequency receiver that picks up all the frequencies in its bandwidth. It currently doesn’t have tuning capabilities but instead it is sensitive to all frequencies in its immediate vicinity.

In order to make the receiver we worked from the following circuit to create the portable “radio.” Rather than of using a walkman PCB, though, we chose to substitute the LM380N to amplify the signal.

The most complicated part of the process was generating enough energy to power our circuit by hand. We used a geared stepper motor from a printer as our supply voltage. The stepper motor created a decent amount of AC power but we put the stepper in series to increase the supply and then ran it through a bridge rectifier to convert it to DC power. We used a 2200uf 50V capacitor, large resistors and signal diodes which helped store, smooth and regulate our output voltage.

Our gear box was helpful to increase the revolutions on the stepper but we attempted to attach a pull start to make the revolutions more continuous. The mechanics of attaching the pull start to the gear box proved to be difficult since there aren’t any exposed gears that we could easily attach. We tried to create our own gears but the gears weren’t precise enough to line up with the teeth on the gear box.

We then attached a hand crank which made it easier to turn the crank by hand but wasn’t as continuous a motion as the pull start. We still had trouble making a secure connection between the hand crank and the gear we attached to we, though. This made it difficult to generate as much power as we had hoped for despite trying a variety of capacitors in an attempt to store energy before delivering it to the speaker.

Our ultimate goal is to transmit our own signal and tune the receiver. We’d like to do this on both an AM frequency and also explore the possibilities of transmitting a signal to a TV. Pirate radio/TV!