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.

Step 1:

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 Car--Amazon.com (less than $5.00)
Servo HS 322--makershed.com
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:

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:

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:

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:

Remove the servo horn from the plastic and screw it to the servo motor.

Step 6:

Screw the motor and servo horn assembly into the plastic runway.

Step 7:

Drill a 5/64 inch hole in the plastic opposite the center of the servo shaft.

Step 8:

Drill a 5/64 inch diameter hole in the 4 1/2 inch long (1 1/2 inch diameter) acrylic rod at the height opposite the center of the servo shaft.

This will accept a piece of 1/16 inch diameter stainless rod--the axle/bearing opposite the servo motor.

Step 9:

Turn the assembly upside down and secure the servo motor and acrylic cylinders to the base.

Step 10:

Solder 12 inch long (you may cut these down to make the project more neat) #22 stranded wires to the 50 watt halogen lamp (Westinghouse lensed spot, gu5.3 base--12 volt).

Step 11:

Drill two holes and secure the lever switch to a piece of 1/2 inch thick acrylic.

Step 12:

Solder wires--one from the halogen lamp, one to the power supply onto the normally open micro switch (this micro switch is rated for 5 amps; that's the minimum acceptable).

Step 13:

Drill holes in the base to accept screws that will secure the Arduino.

Step 14:

Using double sided tape, fasten the six volt battery pack to the base (screw the Arduino in place).

Step 15:

Solder the wires from the servo motor/battery pack and Arduino together.  Tape them with electrical tape to prevent shorting.

Step 16:

Use aluminum tape to secure the halogen lamp wires to the posts.

Step 17:

Use more aluminum tape to secure the halogen lamp power supply wires to the base.

thats a cool little thing, i love useless complex stuff like this, IF ONLY I KNEW HOW AND HAD THE STUFF TO MAKE SOME.....
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!! <br>Build_it_Bob
i thought these were only legends! have you received threats against your safety? how will you harness the energy from the tiny car?
Ha ha ,cool. It's Like the game TIM=The Incredible Machine.
I loved that game!
You can get the solar powered car on <strong>DX </strong>for 2.29 US <a href="http://www.dealextreme.com/p/world-s-smallest-solar-powered-car-37373">http://www.dealextreme.com/p/world-s-smallest-solar-powered-car-37373 </a>(Shipping can take a lot of time though. but is free :) Nice instructable.
Very good deal--thanks for sharing!
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 ! <br>Build_it_Bob
most useless machine 2.0 anyone?
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 &quot;useless&quot; to a new level. <br><br>And someone might accidentally do something useful :)
aaah, the joy of zero stress :D<br><br>making something fun and useless is an art, one that's not practised enough by far<br><br>and yes, some of the greatest inventions are accidents :P
Very good points, both of you.
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?
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 &quot;solar power&quot; 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.<br><br>(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).
The Drinking Bird updated ....Very Nice
@mrigsby; I like it! It's cute, it's solar and it works. *humor alert* Now <em>this</em> is what we should have invested in, instead of Solyndra *end humor alert*. Cheers! :) Site

About This Instructable




Bio: I am an author and a maker. Current projects include Santa's Shop and Little Friend (ultracapacitor powered robot) on hackaday.io. I'm working ... More »
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