Real life coin block

Step 4 Electronic boards

The two circuits were made on separate boards.
One is used as a timer. Is responsible for making the servo rotate 360 degrees each time it activates.
The second is an amplifier. It is used to listen to the mp3 player sound on a common speaker. The two boards work on 4.8 volts from rechargeable batteries.

Timer:
1 - NE555
1 - 100nf capacitor
2 - 1k resistors
1 - 470uf capacitor
1 - tip41c transistor
1 - 10k preset

Amplifier:
1 - LM386
2 - 100nf capacitor
1 - 100uf capacitor
1 - 10uf capacitor
1 - 10k resistor.
1 - 1k reistor.

You can find the pdf file for making this boards in the intro step, or just use a perfboard.

Comments

[txoof]

I'm looking to drive a modified servo with a 555 circuit, but I'm having a heck of a time finding a circuit that I can make work.
I have a few questions about your circuit:
1) What do you mean by a 10K preset? Is that a 10K pot?
2) What might be some substitutes for a tip41c transistor? Is there another NPN type transistor that I can use?

[brunoip]

1- yes
2- there are several transistor that you can use, ask what they have in the store where you buy them.
Regards, Bruno.

[robot1398]

i think preset is not a pot its a kind of pot which cannot be adjusted

[txoof]

Ah yes, and there lies the problem. I'm in a town with absolutely no hobby-electronics shops. Everything I get I have to order over very, very expensive mail. I have on hand a wide variety of NPN transistors. Can you suggest one that would work with this circuit?

[nsutton]

Id like to know the answer to this as well. I am looking to do a small order from West Florida and they dont have the TIP41C. Im curious if the TIP31A would get me by.

[brunoip]

TIP31 may work.