One book on chemical experiments tells about a candle that is difficult to blow out. It seemed to blow out, it seemed to go out - and suddenly it lights up again. And so many times. But the author of Instructables under the nickname Molted decided not to chemize, but to get the same effect in a different way ...
The device is a conventional one, to which an inverter is added (not in the sense of a voltage converter, but in the sense of an element NOT) on an electromagnetic relay with normally closed contacts. Thanks to this, a loud sound causes the LED to go out for a moment, and then light up again.
So, the task of the wizard is to combine everything that is shown below ...
... according to this scheme:
What we used to call an electret microphone, in fact, is a module consisting of the electret microphone itself and the MOS transistor. Previously, a resistor serving as a cascade load was also placed there, such microphones have three outputs. Now they don’t do this, and resistor R1 must be connected externally to a modern two-pin MIC microphone. When power is supplied to this part of the circuit, two components are present at the connection point of the resistor with the microphone: constant and variable. The capacitor C1 passes only the variable component, which enters the base of the bipolar transistor Q1, and the bias is applied through the resistor R2 there. Its load is resistor R3. The next transistor Q2 is connected to it in both direct and alternating current and is loaded on the relay RL1. In parallel with the relay coil, it is good to connect a diode in reverse polarity, but Molted did not. Normally closed relay contacts control the LED D1, the current through which is limited by the resistor R1. The circuit is powered by battery B1 through switch SW1.
You can adjust the length of time the LED remains in the quenched state after blowing out by replacing C1 capacitors of different capacities. To do without formulas, the master compiled a table:
Then he started assembling homemade. He clamped a piece of the breadboard model into the "third hand":
I placed components on it and connected:
I connected the battery with the switch, turned it on and checked how everything works:
Turned off, cut out the details of the case:
Started to install electronics into the case:
Installed:
Closed:
Made a stand:
Put a candle on it:
From such details:
He glued the “flame” and made a bottom for it with a hole:
Attached the bottom:
I put the “flame” on the LED:
Turned on the power:
And you can use:
Molted turned out to be far-sighted with a very cheap Hi-Waote salt battery mowing under the Hi-Watt brand. The short circuit current of such a battery is quite small, which greatly reduces the chances of turning the design into a real candle if something goes wrong.