Intro: Hess Car - Running on Empty (battery)
Everyone makes the Joule thief circuit, but few people have a use for it other than a flashlight.
So when I stumbled on this car in the flea market for $1.00 it gave me a great idea.
This car is nicely detailed and its perfect for the Joule thief circuit where schematics can be found many places on the internet.
Originally the car had 6 incandescent light bulbs all connected in parallel operating on a single AA battery.
Tools and supplies
Number 1 size Philips screwdriver
Joule Thief circuit (the 3 LEDs are connected in parallel to the output of the circuit)
2 white LEDs (2 standard white LEDs for the front head lights)
1 white LED (1 concave lens LED to emit light to the sides thru the clear rear lens, mine was found on a LED Christmas tree light set)
Hot glue gun
Drill and drill bit
Remove the 6 screws on the bottom to release the body of the chassis.
Cut the wires of the 6 incandescent light bulbs and remove them. (3 in the front, 2 on the sides and one in the rear)
Remove the plastic housing that held the rear bulb in the chassis (I melted it with my soldering iron), but don’t cut all the way thru the chassis.
Find a drill bit the same diameter as the rear LED
Drill out the clear lens on the body side until the rear LED fits snugly in.
Hot glue 1 LED in each headlight frame and try to align the 2 front LEDs evenly
Hot glue the Joule Thief circuit just forward of the rear axle gear box (next to the battery compartment)
Press one concave LED in the rear clear light lens in the body (which will light the top Hess logo and rear tail lights)
Optional step: put a piece of silver tape above the rear LED to reflect the light more efficiently thru the lens.
Testing the circuit the 3 LEDs have run on batteries with voltages under 1 volt but are pretty dim at that point.
The car still looks and operates exactly as it did when I got it on the outside.
Future idea is to add a generator on the rear wheels to recharge a AA rechargeable cell when you push it.
But for now, I am happy with the results of this project.