Beautiful solar pendulum build

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By Matt Mets
Posted 2010/06/02 @ 12:57 pm
Category Electronics

On my recent post about building an electromagnetically assisted pendulum, commenter Accomplished chimed in to share their excellent solar pendulum build. Accomplished used the BEAM Magbot Pendulum circuit from the book Junkbots, Bugbots, and Bots on Wheels.

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5 Responses to Beautiful solar pendulum build

Doug on January 16th, 2012 at 9:17 am said:

I’m trying to build this. When I put the circuit together the coil I bought from Solarbotics is getting current, but there is no magnetic field. A compass needle it not defected when placed near the coil. Any suggestions?

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- Joe Duffy on January 26th, 2012 at 7:57 am said:
  
  I am thinking about building one of these solar pendulums. I have been reading about people having problems with them. Please let me know if you got yours to work and does Solarbiotics offer any tech support? Thanks Joe
  
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  Aaron on January 26th, 2012 at 4:26 pm said:
  
  I think the solar pendulum will work as described in the article. The component parts are not that expensive so I would give it a try. See my updated comment below for my thoughts on why I’m having trouble in getting the pendulum portion to “swing.”
  
  I got the circuit to work. I must have originally hooked it up incorrectly. What I ended up doing to assemble the circuit was tape each of the pieces provided by Solarbotics (i.e. the pieces you are told to purchase in the article) to a piece of cardboard in the configuration provided in the article. I then used hand made alligator clip and connected everything based on the article’s diagram. That way I could adjust connections if it turned out I had hooked it up again incorrectly. I think initially I must not have kept all the connection straight in my head when soldering them together.
  
  You can buy tiny metal alligator clips at Radioshack (a couple bucks for 20 I believe – 20 clips would enable you to create 10 “connection” wires). The alligator clips I bought have two dog ears and a hole at the “clip-end” of the alligator clip. That way you can run the stripped portion of a wire through the hole and then bend the dog ears down on top of the wire to hold the wire in place.
  
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Aaron on January 17th, 2012 at 2:59 pm said:

I’m having a similar problem (my parts came from solarbotics as well). My circuit works (sans solar panels) works. I tested it with a 9v and it “charges” the coil and gets the magnet moving. But, when I hook the circuit up to the solar panels, nothing happens. It doesn’t appear the panels need time to “charge up” based on the video above. I’m pretty sure I haven’t fried the solar panels while soldering. And I’m pretty sure I’ve connected them correctly. Do solar panels take a while to charge the capacitors (I’ve never used any before)? Is there a way to tell whether or not the panels are bad (e.g. in a bad light you can see the burned out part)? Any suggestions? Thanks!

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- Aaron on January 26th, 2012 at 4:12 pm said:
  
  Update to my previous comment:
  I used a multimeter to test the volatage at the point the wires from the solar panels connect to the circuit. At that point, the voltage reads approximately the 3V the solar panels are supposed to output (it fluctuated based on the sun).
  I then used the multimeter to test the voltage at the point in between the “magnetic” coil and the circuit. At that point, the voltage was way less than 1V…closer to .5V.
  So, the coil is getting voltage, but it is being significantly reduced from the solar panel output.
  I think this “could be fine” for the type of solar pendulum described in the MAKE article. However, I decided to mod that a bit and add a small metal person onto the “swing seat” portion. This added more weight. So, now I’m thinking that I just don’t have enough volts being output at the magnetic coil to get the magnet/swing apparatus working.
  I’m going to try additional solar panels to see if I can increase the volts to the “magnetic” coil.
  
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