Doubts about a circuit diagram.?

Question

Here's the link:
http://www.electronicshub.org/automatic-doorbell-with-object-detection/

I have been trying to understand the circuit but there are a couple of things that are confusing.

1. The diode type hasnt been mentioned, so if i construct the circuit then is it ok to use something like the 1N4148?

2. I cant seem to figure out where i have to attach the buzzer circuit in the diagram given.

3. And lastly if i make this on a pcb, then how am i supposed to attach a readily available DC Adapter (9V) to the pcb? Or do i have to go about constructing that too?

I am actually considering making the project, so i really need to figure this out before i go and start making it.

Ecko · Answer

The circuit in your link has a number of mistakes and uses non standard values of resistors.

The circuit for "Obstacle detection sensor" in this link is better.
http://users.encs.concordia.ca/~dave/project/elec.html
Another circuit showing the receiver amplifier is here.
http://320volt.com/en/pic16f873-ile-display-gostergeli-ultrasonik-mesafe-olcumu/

The receiver amplifier needs a gain of about 1000, which is best obtained by modest gain in 3 stages. Thus 10 x 10 x 10 = 1000.  It can use an LM324, as can the circuit below. I have added extra parts to detect the signal and operate a relay. It would connect to the circuit in the link at  pin 1 of  U2a, replacing all the parts to the right.

? · Answer

I looked at the schematic...it's badly drawn, contains a serious error, and is weirdly complicated.

For example, what is the opto isolator (The LED/LDR combination) for?
Why is the 9 volt supply connected across the receiver?  It would possibly burn it out.

This looks like a school exercise to demonstrate the working of several electronic components rather than a useful working device.

Trending News

Doubts about a circuit diagram.?

2 Answers