Let's Make Robots!


Seeks light track

Use two motors with separate solar engines; rely on differential sensors to achieve a goal. Poppers are essentially just pairs of solar engines mounted together with motors; they seek out bright sources of light through the differential action of the two solar engine motor pairs.


  • Lenght: 5.3 cm
  • Width: 5 cm
  • Height: 4 cm
  • Weight: 11 g



Qty   Cost
1/2 Solarbotics SCC3733 - 37 x 33mm Polycrystalline Solar Cell 7,30 EUR
1 Cap 1000 uF 1.00 EUR
2 Transistor PN3904 NPN 0,60 EUR
2 Transistor PN3906 PNP 0.60 EUR
2 LDR 07, ø 5 1,50 EUR
2 Voltage detector 1381 4,80 EUR
1 Trimmer 4,7K 0,50 EUR
2 Solarbotics Regular Pager Motor 2 12,40 EUR
    28,70 EUR



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hi friend wat is the use of trimmer & how to use it? as i am trying to make a light follower same as yours. 




wow thats pretty good for solar power.

I have a couple photopoppers too. Surprisingly entertaining little things. Mine are of the Fred/FLED engine variety, acquired some years ago from this guy.

Mine move a lot slower than that, charging for 10-30 seconds (depending on lighting) then running one motor for <1 second. I suppose I could replace the 2200uF cap with a smaller one to speed up charging times (and reduce motor run time).

We like this. What's the charge time / run time ratio? Are those videos in real time?

videos are in real time.

i have not yet measured the charge/run ratio :)