Hobby diy
Electronic pest repeller mice repellant
Electronic pest rat repellents emit high frequency sound waves to create an acoustically hostile environment that effectively repels rodents from protected areas. Sound is inaudible to people and non-rodent pets. It is ideal for environments were the use of poisons is inadvisable or prohibited.
Beware mice, rat and mouse . It is known that a [...]
Electronic door lock
This electronic door lock has a remarkable conception because it uses only one active component.
How does it works ?
To put the relay in tension the 4 buttons S1 - S4 must be pressed. If anyone of the 4 butoons S5 - S8 are pushed the relay dont’s tension ( dont receives supply voltage ).
The supply [...]
Intercom circuit, intercom schematic
In this intercom schematic, the 8 ohm speakers is used as microphone and listening speaker.
The 10K potentiometer controls volume and the total gain can be set with de 5k R. Use a double switch with 2 positions so when one is used to talk and the other one to listen. The switch will be in [...]
