Let's Make Robots!

Solar Spinner BEAM bot


I have been doing some BEAM bot work on the side. Nothing exciting but I wanted to keep making them to get some practice/experience for future projects with solar circuits. This is basically a replica of the solar spinner thats posted here.

I will add more pictures soon. Pictures and video added.

Update: Added a 10uF capacitor between pin 2 and 3 of the 1381 voltage trigger as a timing capacitor. Thanks to Gareth's comments. Added video.

pic1 pic2



Finished picture after adding the 10uF timing capacitor and removing the .22F super cap.

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another question. Does it really matter what diode I use? I had this one laying around so I just used it. I didnt even bother messuring it.

I use mostly 1n914 common signal diodes .... it does make a difference with respect to the voltage drop of the particular diode used.

Also, is there any good place to get those super capacitors cheap? I am guessing ebay?

There is a website called futurlec.com that I get my parts from.  They have 1F, 5.5 V capacitors for $2.50 each.  Their components are very cheap and work well.  Shipping is a set $4.00 for all orders up to $29.00.  However, they have realllllllyyyyyyyyyyyyyyyyy sloowwwwwwwwwwwwwwwwwwwwwwww shipping: took me 15 days to get my parts from Thailand to the US.  Also, if a part is out of stock, they WILL hold your order without telling you until they get more of them.  I always tell them to ship what they have and send the rest later/refund my card.  That always has worked well.

Again Solarbotics, i use the 1 Farads

I haven't tried solarbotics: thier stuff is almost always out of my price range.  How is thier customer service/part quality/delivery speed?

Nice little solar spinner. What size capacitor is that? If you get a chance, check out the EZ solar engine. It can be tempermental but it makes up for it by being very simple and fun to play around with. Plus there are a few different versions to try out.


the capacitors are 3 x 1500uF + 1 x 0.22F super cap. They are all connected in parrallel to give as much juice to the motor as posible. My motor isnt small so it required a little more power to spin with all the component attached to it. At first I only had the 3 x 1500uF caps attached but it just wasnt enough so the 0.22F was an after thought. I need to find smaller and more efficent/torquee motor for these type of projects. Let me know if there any suggestions.

If you change the motor to a low volt version ie one out of a dead cd drive (circa 5V  CD drive motor, they are pretty efficient) and it should perform more like this SPAGM

Try also increase the size of the time_ing capacitor (not the storage super caps), it will take longer to charge but will deliver more power when it fires.

I will try increasing the timing capacitor first. If that doesnt help, I will try replacing the motor. But I think the capacitor should help.

By the way, is there any place I can get the 1381 voltage triggers? I found them on digikey but thats about it.