Update; My age category for the contest is 13-18 because I am fifteen. :)

Yes, the title explains it pretty well. In this Instructable I will show you step by step how to construct a light sensitive, solar powered, robot. All you need is some parts that can easily be found in the trash or in your backyard. I built mine totally from trash.

Step 1: Bits and Pieces


2- 1.5 volt motors
1- AAA battery pack that holds 2 batteries
1- On/Off switch
1- Old solar powered garden light
Random bits of wire
zip ties

And something to use as the chassis for your robot, I used some bits of Erector Set parts, but almost anything can be used.


Needle nose pliers
Wire stripper
Scissors or wire cutters
A vice grip (optional)
Magnifying glass (optional)
Soldering iron and solder (not optional)
Glue gun and glue

Step 2: And So It Begins...

For this step you will need...

Screw driver


Begin with the old solar light, you will have to open up the top and remove the solar panel and control circuit without damaging any of it. Follow the notes on the pictures to see how. Make sure to read all the notes as some wires need to be cut, while others do not.

Step 3: Assemble the Curcuit

In this step you will need...

Soldering Iron, solder, motors, switch, and the battery case.

When wiring the motors, don't worry about polarity (positive and negative), you can fix which way the motors spin by rewiring the motors later on. How the are wired dictates how they spin, and which way you want them to spin is going to depend on your frame you mount this on.

I guess while we are on the subject of the circuit I should explain how this works...

The circuit from the solar light is meant to charge a battery from the panel during the day, and discharge that battery through 2 LED's at night. By replacing the LED's with motors and putting in a more powerful battery pack, we do two things to this circuit;

1. The circuit will still charge the batteries, but only while the robot is on.

2. When the robot is in the dark it will run at half power, and full power in the sun. Meaning the motors will run slowly in the dark, and faster in light.

Step 4: The Frame

In this step you will need...

Something you can modify into a frame or an erector set like what I used.
Hot glue gun
zip ties

In this step you need to mount the circuit onto a frame. For my frame I used some random pieces from an erector set, but there are many things that can be used. The shape of my robot was inspired by robomaniac 's beetlebot v2 , which you can find here .

Follow the notes in the pictures to see how to mount onto a frame like mine. If you have one different than mine, you are on your own for this step.

Step 5: Testing and Rewireing

In the below video you can see the robot accelerates when a light is shone on it, but spins in a circle because one of the motors was reversed.

If this happens to your robot all you have to do is re-solder the motor wires in reverse. So the one that used to be negative is now positive.

Step 6: Video of Finished Project

In the below video you can see the finished robot running forward.

I hope you enjoyed this Instructable! Any comments or constructive criticism is very welcome!

<p>thank you </p><p>mehdi zangiabadi</p>
<p>guys ho do i use the hpd wires and connect them </p>
<p>guys ho do i use the hpd wires and connect them </p>
<p>guys ho do i use the hpd wires and connect them </p>
<p>what up</p>
<p>im the next odell becham jr </p>
<p>you have to use hpd wires</p>
<p>wat up attacker 2</p>
<p>no you can't</p>
<p>can you put a device in it so it can be controlled by mind</p>
<p>Hi I am doing this for a project do you have to use any color wires please get back to me asap</p>
I am very knew to robotics and i have a few important questions:<br>What exactly does a soldering iron do?<br>Is a circuit board (i think thats what that green board is called) needed for any kind of simple robot?<br>If so, must i make a new curcuit board or can i recycle an old one (such as from an old rc car).<br>How much would a soldering iron cost in US Currency ($)?
Can it be any 1.5 volt motor?
It can be *most* any 1.5 volt motor. So yes. Kinda.
Very nice idea. It is super simple and introduced me to robotics. Thanks very much for the great instructable
what is panel mounted that was used there and where can i find that thing ? please do reply i really need it for my project .. thank you so much :)
Sorry for the delay in this reply. The panel I got came from an old solar garden light. You can get them at any Walmart or garden store.
where can i get or how can i made the control circuit?
The control circuit (as stated in the instructable) is obtained by taking apart solar powered garden light. Practically every garden light has one in it.
you could use some of the ideas of the beetlebot to make this robot automatically void things.
Where are such solar-powered lights used usually? In the yard? They charge during the day, and then shine at night? I've never seen such stuff.
Are you from outside the United States? They are very popular here within the urban communities. I don't know about Europe, but you can find them at almost every garden section in any store in the U.S.
Yeah, I'm from Russia. Thanks for the info and the i'ble!
Good to know. Thanks for commenting!
Could I put sensors on the front to make it Solar powered and sensored? I'm in 7th grade so would this be too hard for me?
if u did it would not be from trash
There already is a sensor on the front... Do you mean obstacle avoiding?<br><br>This should be an excellent project for a 7th grader!
Do you think that this will make me win a science contest for kids 6-8 grade?? I really want to win this!!
If you really want to win a science fair, I suggest you build my version 2. Which is obstacle avoiding. I have no instructable, but I would be willing to send you pictures and instructions if you would like. :-)
thank you!!please send the pics!!!
Ok, just send me a Private message through instructables with your email. I'll send instructions and pictures as soon as I can compile them. (shouldn't take more than a day or two)
Thank you!! I'll definitely use the instructions!
Yess!!! I mean obstacle avoiding. Sorry for any confusion. Thank you!!
does any one know if you can somehow attach something to this to make it r/c sorta kindish ?
IF you happened to have a rc car that drove with a differential (0 degree) drive, you MIGHT be able to jerry-rig the circuit to control the two motors... :-/ Although it seems to me like a waste of a rc car and time. Unless your overall purpose was to create a rc robot shaped like a bug.If you have something specific in mind let me know and I'll see if I can help.
man, if i get the chance to make this i'm going to customize the s@#$ out of it......
Hells yeah! :D
I very much like this sort of simple design. I'm wondering, however, if there's an easy way to make this light seeking. Maybe if you had a pair of light sensors?
Actually, if you had two identical circuits from solar lights, you could just put one motor for each circuit, (or two on a tank!), and criss-cross the light sensors and have yourself a solar powered light seeking robot.
it would be really cool if you could have the motors alternate so it walks in a jerky side to side motion.<br>cool robot, love the tripod
This is realy good it look like very simple.try to make this<br>
looks pretty good made me want to do a solar powered calculator or a piano<br>very original
I'm sorry for asking here, but what is the green mat called?
craft mat, cutting mat, etc
Do not think I made a little robot is so simple.
What? I am having trouble understanding your question/comment.
:) It's because I'm from Russia, I know English bad and I use Google's translation. The design of the robot is very simple. Liked it.
That is awesome! Im glad you liked it, thanks for the comment!
<p> martzsam,<br> Cool project, but I don't quite&nbsp;understand what is going on.&nbsp;<br> <br> Do the batteries need to be charged to get the 'nominal' motion and the extra light on the cell adds the additional power to increase its speed?&nbsp;<br> Said another way, without the batteries does the robot move in the light but only at 1/2 speed?<br> <br> Or is the extra light only hitting the light sensor and that's what's increasing the speed of the bot?&nbsp; (This wouldn't make sense because the light sensor is supposed to turn off the device when it gets too light)<br> <br> Did you have to do something to the light sensor since normally the light sensor turn off the power to the circuit when it is sensing light since this function is to turn on the 'load' when it gets dark?&nbsp; Said another way does the robot stop moving in bright light?<br> <br> Are the batteries wired in parallel or serial?&nbsp; If serial then I wouldn't think that they were being charged at all since the circuit would be designed to charge a single cell and would not provide sufficient voltage to charge two cells.&nbsp;<br> <br> It would be nice if the robot would continue to charge the battreries when switched off.&nbsp; Have you cheked that there is no current going to the betteries when the switch is in the off position?&nbsp; Without knowing the circuit design we really aren't sure what's going on in it, like it operation in the off position, how the light sensor works, or if the battery charging circuit has over charging protection.<br> <br> Thanks for posting the project matrzan!&nbsp; I really light the idea!<br> <br> Best Wishes</p>
This might explain some things;<br><br>1. The robot doesn't work without the batteries, I worked it so the robot starts with a full charge, then maintains that charge with the panel while it is running. The solar panel does not directly power the motors. It like just adding on another battery that never dies in parallel. <br><br>2. The batteries are wired so their gross output is only 1.2 volts, not 2.4. This allows for the 3 volt soar panel to do its job charging them even in low light. In other words, yes they are wired in parallel. (which is probably important and I should update that...)<br><br>3. There is absolutely no current going to the batteries when the switch is off because the switch is right on the positive out from the pack.<br><br>4. And when you said,<br><br> &quot;Or is the extra light only hitting the light sensor and that's what's increasing the speed of the bot? (This wouldn't make sense because the light sensor is supposed to turn off the device when it gets too light)&quot; <br><br>you are totally correct, because the panel doesn't power the motors directly, the circuit relies on the light sensor to tell it when to speed up or slow down.<br><br>I really hope that made sense.

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