DS

This is the Simple Homemade Melody Door Bell Circuit Diagram. In most of the homes the door bells are conventional ding-dong type. Most of us don’t like its sound. Due to mechanical moving parts with spring mechanism its long term durability is questionable. I had also one such door bell in my home. After a period of time its performance deteriorates and one time it becomes completely intolerable because of its noisy irritating sound. The new types of door bells available in market are bird sound door bell. They are costly. and even I didn’t like it because of its high frequency and high volume sound output.     Simple Homemade Melody Door Bell Circuit Diagram   So the idea came into my mind that why not to build a very simple door bell with few components that gives nice melodious output and that is at the less cost also. So I build this door bell with all the items available in home. Let us see how I have made it. Description First collect the required compone...

Because I’m old school, I wanted to build a Garage Door Closing circuit without relying on integrated configurations (555 timer etc) to keep it simplistic. The circuit closes the garage door after two minutes with C3 and four minutes with the addition of C2. The timer relay is surprisingly accurate (+/- five seconds). Another feature is to ensure that the garage door actually did close, such as if it’s stopped mid-operation by the user. Description: S3 (magnetic N.C.) is located at the garage door and activates the circuit when the garage door opens. RL1 is the reset timer. It’s maintained in the “on” position for two minutes by C3 while the trigger capacitor, C4, is charged. RL2 is the conduit, directing C4 to either RL3 or R1 to ground when off. Purpose of R1 is to prevent arching across contacts and a fast discharge. RL3’s contacts are connected to the Garage Door’s Momentary Switch and is sustained “on”  for a half second by C5. When C3 discharges to the cutoff voltage of RL1, ...

This automatic door opener can be made using readily available components. The electromagnetic relay at the output of this gadget can be used to control the DC/AC door-opener motor/solenoid of an electromechanical door opener assembly, with slight intervention in its electrical wiring. A laser diode (LED1) is used here as the light transmitter. Alternatively, you can use any available laser pointer. The combination of resistor R1 and diode D1 protects the laser diode from over-current flow. By varying multi-turn trimpot VR1, you can adjust the sensitivity. (Note that ambient light reflections may slightly degrade the performance of this unit.) Initially, when the laser beam is falling on photo-transistor T1, it conducts to reverse-bias transistor T3 and the input to the first gate (N1) of IC1 (CD4001) is low. The high output at pin 3 of gate N1 forward biases the LED-driver transistor (T4) and the green standby LED (LED2) lights up continuously. Circuit diagram : Laser-Guided Door O...

Description    In all the houses exist the bells in the door. All want, they have the possibility of being possible to change the intensity, the tone of sound. With this circuit we have this possibility. With the materials round the gates, we can change the sound. For the materials that exist in the circuit the frequencies are roughly 5 KHZ and 2 KHZ. The circuit functions only for small time interval afterwards the pressure of switch. Simultaneously with the sound we have also optical clue from LED D2. Changing the capacitors C2-C3, with different price of capacity, we create new sounds. Circuit Diagram Part List R1=470Kohm R2=22Kohm R3=3.9Kohm R4-5=330 ohm R6=2.2Kohm R7=1.2Kohm C1=22uF 25V C2=470uF 25V C3=1 uF 25V D1=1N4001 D2=LED RED 3mm IC1=7413 Q1-3= BC 550 Q2= BC 560 BATT=4X1,5V or external pack 6Vdc SP= Speaker 8R /0,5W All Resistors is 1/4W 5% Source -http://users.otenet.gr/~athsam/melody_door_ringer.htm