Picture of Rigsby Machine

Complex, costly and performs a useless task.

The solar powered car darts from its starting position away from the lamp--only to be returned and repeat the cycle.

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Step 1:

Picture of
The runway, in its lowered position, closes a normally open micro switch--allowing power to a 12 volt, 50 watt halogen lamp.  This causes the solar powered car to race down the runway out of the light beam.  An Arduino microcontroller causes a servo motor to raise the runway, thus opening the switch, shutting off the light and causing the car to roll back to the starting position.  The runway is lowered and the process repeats.


Solar (less than $5.00)
Servo HS
Power supply for lamp--use a low voltage undercabinet supply of 50 watts or greater; regulated 12 volts supplies may not provide enough starting current to illuminate the lamp


#include <Servo.h>

Servo myservo;
void setup ()
void loop ()
delay (1000);
myservo.write (30);
delay (50);
myservo.write (35);
delay (50);
myservo.write (40);
delay (50);
myservo.write (45);
delay (50);
myservo.write (50);
delay (4000);
myservo.write (45);
delay (100);
myservo.write (40);
delay (100);
myservo.write (35);
delay (100);
myservo.write (30);
delay (100);

Step 2:

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I cut a 12 inch long by 1 and 3/4 inch wide strip of 1/4 inch thick acrylic.  I attached a 12 inch by 3/4 inch by 1/8 inch strip of acrylic to the side.  I attached the servo horn to one end of this arrangement.

Step 3:

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I added a "wall" to the other side, then discovered that the runway is too wide.  The car can turn sideways or even backwards!

Step 4:

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The choice was either to cut new pieces of plastic and do this right or go for the quick fix. 

This was my first experience with Sugru (soft touch silicon rubber that moulds and sets permanently).  This stuff is great!  Squish it in your hands like clay, put the pieces together and wait over night.

Now the car can't turn around or get wedged in sideways.

Step 5:

Picture of
Remove the servo horn from the plastic and screw it to the servo motor.
jtadelman3 years ago
thats a cool little thing, i love useless complex stuff like this, IF ONLY I KNEW HOW AND HAD THE STUFF TO MAKE SOME.....
MikeTheMaker (author)  jtadelman3 years ago
Thanks! Sometimes it's fun to take stuff you have and make something just because you can.
mrigsby, I thought a few of your ibles looked familiar to me ! This still is such a neat project...time to check out more of your creations!!
i thought these were only legends! have you received threats against your safety? how will you harness the energy from the tiny car?
Phoenix783 years ago
Ha ha ,cool. It's Like the game TIM=The Incredible Machine.
I loved that game!
shawa13 years ago
You can get the solar powered car on DX for 2.29 US (Shipping can take a lot of time though. but is free :) Nice instructable.
MikeTheMaker (author)  shawa13 years ago
Very good deal--thanks for sharing!
jstarkmuth3 years ago
I'm quite sure that this could be built with a much simpler analog control circuit not requiring an expensive microcontroller. But I might be undermining the philosophy of uselessness here. ;-)
mrigsby, your last staement is poetry in action. Nice project !
godofal3 years ago
most useless machine 2.0 anyone?
MikeTheMaker (author)  godofal3 years ago
If we don't worry about sales potential, complexity, doing things the best way possible, cost, etc.--I think there are minds in this community capable of bringing the word "useless" to a new level.

And someone might accidentally do something useful :)
aaah, the joy of zero stress :D

making something fun and useless is an art, one that's not practised enough by far

and yes, some of the greatest inventions are accidents :P
Very good points, both of you.
pdee-13 years ago
I can't help but think the solar panel on the car is superfluous because the lowered ramp would cause the car to roll downhill anyways... It just seems that some tweaking would make the function of the parts a bit more obvious and aesthetically pleasing
I was thinking, also, that the lowered ramp and gravity made the car go. Or is that part of the uselessness of it all? That the lamp doesn't really have a purpose?
MikeTheMaker (author)  hammer98763 years ago
I had a few solar cars and I wanted to do something with one of them. The ramp does not lower enough to make the car roll on it's on--it is the "solar power" that moves the car. I wanted to put things together and have them work; not optimize, not make beautiful; just pieces together that do something.

(Yes, I could lower the ramp enough to make the car move--but I didn't build an end to the ramp. It would be tricky to keep the car from running off the end by lowering the ramp for movement).
awoodcarver3 years ago
The Drinking Bird updated ....Very Nice
sitearm3 years ago
@mrigsby; I like it! It's cute, it's solar and it works. *humor alert* Now this is what we should have invested in, instead of Solyndra *end humor alert*. Cheers! :) Site
Electorials3 years ago
haha that's really nice!