Miller engine .... but it dose work

Ok it looks a mess but it dose Work .... So why am i posting this .... couple of reasons ... first off its my first proper working circuit and i have a few questions about it.

As i have  very little to work with im delighted to get this to work (hopefully that will be changing shortly .... just have to get paypal sorted with my bank and ready to order a few bits and pieces.)

So we have a miller engine ... i tried this before using another layout with a pnp transistor also used in the circuit but couldnt get it to work ... saw this one without the pnp resistor and it works for me.

Incase you are all wondering whats with the crazy set up ... lol lol got a thing called snap circuit pro in a charity shop for 3 euro and comes in handy for setting things up on .... its like a crazy sort of breadboard.


Question 1) circuit has a diode ... i find if i run it without diode it works fine but different eg light flashes stronger but not as often .... with diode it flashes weaker but about 8 times more in the same length of time ... What would the reason for this be.

Question 2) will work with the two solar cells .... Not sure of there specs .... they each charged a 1.2v rechargable battrie in a solar light .... but if i add a third to the set up the circuit wont work. So im wondering how to get more power to the circuit ... even though it works its very weak .

Ok just added a video .... again not much to look at .... but first time using u tube and creating a video ..... just wanted to try it out and see dose it work .... But you can see the motor being powered from the solar charged capacitors.

1) Looks like the diode is

1) Looks like the diode is being used to raise the voltage at pin 3 on the 1381, which makes the circuit fire at a different threshold voltage. This changes how much the capacitors are allowed to charge before the NPN transistor is turned on.

2) The two solar panels in the photo are connected in series, so their voltage is added together. If you add a third panel in series the circuit should still work (make sure you check that the polarity is correct), but it won’t help much since all you’re doing is adding more voltage - what you need is more current to charge the capacitors with.
If you have two more panels, try adding them in parallel with the two you already have connected. This will give you double the current so the circuit will charge twice as fast.

If you want to make the capacitors charge for longer before the NPN transistor fires, you could try moving the diode to the other side of the 1381 to shift the threshold voltage up further.

use cap of 1000 micro

try using a capacitor of 1000micro . as would take  less time to charge the capacitors.


Did a little more

Did a little more experiminting with this … would get more results only for weather very bad at this time of year for using solar cells. But did get a few minutes of bright sunshine and tried a few things.

1) used a tiny motor instead of led. And found with diode in circuit motor wouldnt work … could feel a ticking inside the motor but it wasnt turning … i then changed the capisitor down at the voltage regulator from a 47uf to a 220uf and motor then worked … so going to try a few different sizes there and see what works best …

2) rigged up 4 cells … now have two in series and two in parallel which is giving me more juice … but as i have no more thats the best i can do … but in direct sunshine motor turns over quite well.

going to try add another 2200uf cap to the main cap if i can find one and see how the extra storage helps … as in direct sunlight this charges more or less straight away.

Managed to find and add a 1000uf capisitor so now have a total of 2,200 + 1,000 + 470 = 3,670uf  still feel it could take another 1000 if i find one and will run better.

I was curious about your new

I was curious about your new solar cell configuration. If I read it correctly you might be able to benefit from a different setup. So you have two cells connected in series, two connected in parallel, and those are both connected how to the regulator? Usually you connect cells in series to acheive the voltage you’re looking for and then connecting those strings (all the same voltage) in parallel to your circuit to increase the current output.

Probably just the way i

Probably just the way i explained it but nothing special about my solar cell connections have two cells connected with the positive wires linked and then there negative wires linked … have another pair linked the same … then i linked these two together in series.