About code locks wrote more than once. However, most of them are difficult to repeat. Design suggested by our Bulgarian friends (the journal “Radio Television Electronics”), devoid of this shortcoming. For opening this lock simply insert the key and complete the circuit with the resistor R1 a certain value (it is mounted in the housing of the key). If the resistance will be different from that specified on the schematic, the relay does not work and the lock will not unlock.
Lock in idle mode (no key) consumes Ocala 16 mA and 24 mA with the key.
Relay — 6V, 20 mA. Transistors V1, V3 — low-power silicon, for example, KT315 with any alphabetic index.
Recommend to read
BARRIER TO DRAFTS
One of the ways of dealing with skvoznyaki in a modern apartment is to install a rubber door sealer, available in hardware stores. But here's the thing: if you provide a large preload,...
FEET WET
When mixing plaster or mortar in brickwork, just by walking through tall wet grass or deep snow skiing, and in many other situations of a leg above the boot be-spattered or wet. This...
