The device is useful for a model fire truck and a guard system. The intervals between the signals and their duration is controlled by changing values of electrolytic capacitors C1, C3, fixed resistors R2, R4 (see diagram). Sound effects you can Supplement the indicator light, replacing the resistor R3 with a bulb from a pocket lantern 2,5ВХ0,1A. Output transformer and speaker from any small-sized transistor radio.
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WITHOUT A DRILL
The hole in the metal plate can be obtained without drill: it is enough to bend it and work a round file or a needle file. This technique is especially useful when you want an oval hole....
LIKE MASON
Love your magazine and want to share with readers his "invention". A similar device was published in the magazine, but mine is more versatile. And took it when I had to lay down a brick...
