Picture of Solar Powered Miniball Wannabe
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This miniball project has its roots in the old BEAM Miniball kit published by Solarbotics. It's still a cool kit, so we're going to show you how built a simpler version. This project is spearheaded by Mr. Jerome Demers ( aka Robomaniac ), our intern at Solarbotics!

This robot uses a solar engine circuit. A small solar cell by itself generally doesn't have the power to make a motor move, so you have to store this power up in a capacitor, which is a small battery-like storage device. When the circuit sees that there is enough power stored, it releases it in a burst to the motor, getting useful work.

With this project, our solar engine will be powering a small car in a large plastic sphere!

This technology of using minimal electronics and simple mechanical design is call BEAM robotics.

The Miniball itself was originally invented by Richard Weait of North York, Toronto.The Miniball is a amazing robot - it uses a simple circuit and the robot itself proves to be very capable, rarely getting stuck. The Miniball is mechanically complex and electronically simple. (But don't worry - the mechanical part is still pretty easy)

In this case, we aren't going to build the original Miniball, but a smaller, more basic wannabe version. This robot is extremely simple and can take a beginner less than 2 hours to build.

The original Miniball has a geared motor that moved as a counter weight around a fixed shaft inside the plastic ball container. As the motor tries to move the weight forward, the ball starts to roll in that direction.

In our case we have a motor with wheel, which spins the ball forward as it runs.

Imagine this like a hamster in a ball - it's almost the exact same thing! But in this case, we're feeding our hamster with photons!
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Boo - not working. Diode is correct; used a magnifying glass to inspect my soldering and I don't see any overflow. Switched motor leads but then read elsewhere that just changes the direction of the motor. Tested the motor again and it works. I am using a 1381e instead of 1381c but didn't think that would matter. Thinking it has to be a short and I just can't see it. How do I test? Thanx all.

Kelly Smith made it!1 year ago

Thanx for the easy follow along!

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very cool

imbiglarry1 year ago
Too cool.
I really have to try making one of these!
pcastro52 years ago
Ok. Can I use hook-up wires instead of using breadboard wires. If I can't. Where can I buy a breadboard wire?
Caquin3 years ago
Working on this with my 10 year old.
Heads up on the breadboard wire. This is not in the parts list but it is essential to keeping the wire from contacting the board.

We are headed over to Radioshack to find some breadboard.
 how do you get the ^sphere^
I when to my local art store, they use those sphere for home made Xmas ornaments.

They are really cheap, they where on sales for 0.99$

They had 2 size, small like the one in this instructables and much bigger. (4 inch )

have fun!
opps missed can you come here an read up one , oh ill copy an paste would a square work or does it not power enoght to flip over?
i dont think it will have enough power so try using the ball/capsules from the toy dispenser thingys.
i hate being dumb an lazy could we just trade ive lots of stuff taken apart lol you could build amys , live vid cam races sounds fun , oh wait it rains here to much .
how many workerballs can i get for 50,to 100 ft of cable wire , my dad collected junk too lol
arts an craft stores sell the P.balls , would a square work or does it not power enoght to flip over?
here's the one i bought
Shrio4044 years ago
Adding up totals now... im at around $23 for electronics and another $11 for sphere
jmhn4 years ago
Will the robot work in artificial light?
pobturtle4 years ago
How much do all the part cost?
cyprian9164 years ago
this is sick!!! i'm Definitely building one.
riverreaper5 years ago
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if your lazy why are you on this site?
(removed by author or community request)
" cant you tell when someones joking " um yeah its text so it's kinda hard to tell whos joking and whos not....which is why they created emotes..... " look how lazy you are replieing stupidly 5 months latter"\ hardly lazy... just saw this page the other day which is when i commented, and as for how long the comment was up for no clue don't pay enough attention as to when people post as to what they post
you said why im on this sight if im lazy so i took a look at your an thats my coment on how much work you put into it , du , you one of them whom just loioks for resons to fight or put some one down , to make yourself look better ...but most can see by how much work youve put into doing instructables yourself by going to your sight . im on here because im an inventer at heart , not to buy an over priced item , that a 6.00 cat toy will do
For a limited time only, get the Solar Powered Miniball Wannabe for 3 easy payment of 320$ and GET FREE SHIPPING! ps- I am not kidding
thats ok ill wait till gas gets cheaper an go back to wipen out our ozoin layer
AustenQn5 years ago
Is there a remote controll?
JingleJoe5 years ago
Can I get a circuit diagram for this?
Solarbotics (author)  JingleJoe5 years ago
Spiffing, thankyou :)
Mdob5 years ago
Hi i was wondering if you could use a 1F cap instead of the 0.35F; would it just take longer to charge and have a longer burst of power?

Thanks for your help
Solarbotics (author)  Mdob5 years ago
 yes it will have longer burst but will take longer to charge.
mimib12305 years ago
This is great so far! The only roadblock I've come across may sound amateurish but this is new to me:

I bought the bundle from the website. I can't tell the difference between the two black pieces (the transistor and the voltage detector) to be able to know where they go. Any advice? They are not labeled at all.
Solarbotics (author)  mimib12305 years ago
 I never say non label transistor! I check the roll of the 2N3904 and 1381 and they are both mark.

The 1381 is writting 381, the 1 is really hard to see/missing.

You can test the transistor because there is a diode between the base and emitter.

Take you multimeter in diode mode, then put the component flat side on the table. Touch the middle pin and the right pin with your multimeter and you should read around 0,6V. If you don't that is the 1381. 

Good luck!

caver015 years ago
 Mine does not work. I am measuring a short across the leads of the .35F cap and I get a short. Bad cap?
Solarbotics (author)  caver015 years ago
How do you measure your short? With the beeper on the multimeter or ohm?

I used the beeper and I heard a beep too! I took the ohm and got 4M on a 4700uF cap. 

Be sure to check all the connection and polarity of all the components.
jwystup5 years ago
When I finished my "miniball wannabe" it didn't work. After staring at it for awhile and looking at the setup of the <a href="">Solar Powered Battle Symet</a>, I realized that I put the diode on backwards. I wanted to note to anyone else trying this instructable that the diode needs to have the dark line towards the bottom (in the orientation of the picture above)
Solarbotics (author)  jwystup5 years ago
 Hey, I added a note in the picture so people do not get confuse.


I am happy that you where able to find the problem on your own! Great job!
Solarbotics (author) 5 years ago
kal00: Adding a second capacitor doesn't take over charging while the first is discharging. The solar cell simply keeps adding its power output to the power being dumped by the MSE circuit.

What it does do is let you store more power before activation, for a more impressive power burst!
jwystup5 years ago
BTW if you weigh the driver down it wont tip unless it has tremendous speed
probably about 0.5 kg would do it
Solarbotics (author)  TheSmartLemon5 years ago
 Yes but remember that the pager motor has no torque, so 500gr is WAY to heavy and the pager motor will not be able to roll the robot around.

You really need to make that robot light and have that third top wheel.
oh well mine has about 2 kg torque so it can withstand it

it looks exactly the same a well(the motor)
santy225 years ago
 Just here to say remember THIS
Who doesn't!!!
total cost?
Not much if you just take the components out of old broken devices. ; D
some parts can not be find in broken stuff...


if you search really long you might find all the stuff.

the plastic ball will be the hard part.  The 1381 is second, solar cell comes in third.

You could make a solarengine with a other type of circuit because the 1381 is hard to find, I never found one in more then 10 years.

good luck!

If you can't get a 1381, this should work ( I have not tried it yet )
step 2
this link

23$ and you will also need some paperclips, 3 cm of wires and the plastic sphere.

Then you have everything to rock and roll!
lowercase5 years ago
Is it tightly sealed??

PLEASE, PLEASE put in in the water, I want to see a video!

Chikara5 years ago
mmmhh delicous photonss.......
jam BD5 years ago
ha ha ha ha soo cooooooooooooooooooooooooool =D
the ball is awesome
Ankush5 years ago
Brilliant, will get back to you if I have an queries :)
otoupalik5 years ago
 Hehe that is really neat. Sometimes the simple things are the most entertaining.
This is brilliant, I am so building one. Thank you very much

Brilliant design and execution. Fantastically documented too :)
Skyriam5 years ago
how about putting 2 capacitors instead of one? when capacitor 1 finishes charging and goes active, the second capacitor is already charging, that way the robot can sustain a constan flow of movement. 
imrobot5 years ago
WAAA!!! so cool!

i think i'll go build this! thanks!