|Final view of our doorbell project prototype.|
We test this doorbell with several YOUHE access control systems and it works well with all the tested models.
In this design NE555 is setup to obtain 840Hz – 860Hz output with above 80% duty cycle. To get more effective output we use small 3.5 inch, 8Ω tweeter with our prototype design.
The PCB design and schematic of this design is available to download at elect.wikispaces.com.