Solar Challenge: Beam Robot

by Angela Perrone & Naoki Ishizuka

Meet BoomBot, an audio cassette tape robot that is powered by the sun,

BRINING HIM TO LIFE

We began testing out a beam circuit with one solar panel and two capacitors in parallel, and were able to light an LED.

To get more voltage, added a second panel in series and upgraded our voltage regulator to 4.2-volt voltage regulator. With this circuit set-up, we were getting voltage reads of 4.23-4.55 volts.

We tested this on a small DC motor, and the motor would not move. With a power supply, the motor moved at .5 volts, but nothing with this circuit.

We tried as many set ups as we could, changing capacitance at both the parallel portion of the circuit as well as the capacitor at the voltage regulator.

These were our findings with Ohms Law:

New motor 1.5 ohm –> 4.25-4.55/1.5 = 2.8AMPS – 3AMPS

Tiny motor 1.1 ohms –>　4.25-4.55/1.1 = 3.8-4.1 AMPS

We put our motors aside and tested with two different DC motors and were able to get them moving with the original two-panel, 3 capacitor circuit set up.

Jeff’s motor 63ohms –> 4.25-4.55/63 = .067-.07 AMPS

Mathura’s motor 16hms –> 4.25-4.55/16 = .27 – .28 AMPS

It was here that we realized, we needed to use motors with a higher resistance, in order for them to run on the low current being sent through the circuit.

SETTING UP THE ROBOT HOUSING

We tested our set up on the breadboard and got everything working!

SOLDERING IT TOGETHER

POST SOLDERING BOARD

We are not measuring the voltage we were getting previously. Before when we had up to 4.55 volts, now we are getting from our capacitors, a read of about .74 when fully loaded up. However, this may be due to the lighting.

TO THE SUN
We brought BoomBot out to meet the sun. With full exposure, both motors moved with .9 volts measured at the capacitors.

Ohms Law: V=IR
.9v /63 Ohms = .0143 amps
.9v/16 Ohms = .056 amps