Let's Make Robots!


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'Sunflower' - Solar Power Smart Head V5

I made this bot for my daughter's 6th birthday present. I used as many scrap parts as I could scrounge up (Situation = Normal). Most of the capacitors are scavanged, along with the 3.5" Floppy drive motor coil, the leds, all the wiring and connectors and the battery. I made the frame around the solar panels out of copper wire and copper tubing, soldered together to create spring loaded hinges for both 'leaves'. This little guy will sit happily watching the brightest thing it spots, rotating to brighter sources of light, should they becoome available. He moves about every 4 or 5 seconds for about 20 degrees (unless he is locked onto a bright object) just slow enough to be plant like. He has a violet/pink led in the center of his flower and another red led on his radio shack round circuit board. I'll add a video when I get a decent one. Video added.

The schematic and layout.



Hinged panels demonstrated.



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do you know of a 74HC240N solar engine that does not use a 1381 voltage trigger? I was reading this page http://www.beam-wiki.org/wiki/Power_Smart_Heads and according to it, there is suppose to be a solar engine that doesn't require 1381s... "A SPSH4 design is next that replaces the 1381 with two transistors and provides dual motor drivers." I cant seem to find that circuit. Can anyone help?

Sorry if this is not appropriate to ask here.

The original Solar Power Smart Head circuit uses a transistor/240 based SE. You might try that one out. The circuit does essentially the same thing one as the one I used for this guy.

As far as I know, there was never a completed SPSH v4.


I may not be the best person to answer, but I made a robot using a similar circuit to this one.  Instead of a 74HC240, I used a 74AC240, and I didn't need any motor drivers to run the motor.  There also is a solar engine called the FRED solar engine.  I have been impressed with its efficiency, and all of the parts are available at radioshack.  However, don't get it mixed up with the FLED solar engine, which is rediculously inefficient.

Is this the FRED you are talking about? http://raysbeambots.solarbotics.net/FLEDtutorial.htm

I have worked with FLED engine before, but wasnt very happy with it. I am assuming they both use flashing LED in the circuit, correct?


yes they both use a flashing LED.  I found that red works a little better than green.

yes it is.  You only need to build one of the solar engines, not both though.



Lots of useful BEAM stuff at this wiki site.

thanks, there is sooo much stuff around! trying get wrap my mind around it.

this is awesome! Is there anyway you can make a parts list of what you used? I see you used a 74HC... chip. Is there anyway you can make something similar without that chip? 

it uses a 74XX240, which is 6 inverter gates in one 20 pin chip.  You could wire a NAND gate into an inverter by connecting both inputs together with a wire.  Or, if you really want to get DIY, you could make 6 NAND gates out of transistors and wire both inputs together.  I built this circuit, and it works pretty well with about 5 volts.  Link to schematic for the gates can be found here.