Parking radar K3502

[keykeybro]

Hi, I know that there already was discusstion about this radar, but i can't find it any more. What I have to do in this scheme that this sensor shows the distance of obsticle? It beeps the same no matter if the obstacle is 10 cm or 1m away from it.

Maybe someone of you already find out how this scheme works and which component does what or how the signal goes through the circuit, specially what happens at IC3, IC4 and IC5. And maybe someone can explain how the time diagram can be made.

It is for my school project. And when my project would be done I promise, that i will put in this forum in case someone need it.

I would be very grateful of any help.

There's information about K3502: https://www.electro-tech-online.com/custompdfs/2011/06/illustrated_assembly_manual_k3502.pdf

IC1- an electronics timer by CMOS CD4060 which is CMOS 14 Stage Ripple-Carry Binary Counter/Divider and Oscillator.
IC2- CD4020 is also a counter
IC3- CD 4068 NAND/AND gate
IC4- CD 4093 NAND Schmitt trigers
IC5- CD 4049 Invertor
IC6- TL074 Operational Amplifier

 

[keykeybro]

What is the purpose of those invertors near sensor1 and what do that schmitt triger(N4) before them?
Plz Help

 

[crutschow]

This was the previous thread: https://www.electro-tech-online.com/threads/parking-radar-k3502-help-please.118653/

In that post I stated:

"Sensor 1 is the transmitter so it has some paralleled inverter gates as drivers to the transducer.

Sensor 2 is the receiver so it has a couple of op amp amplifiers to amplify the reflected signal. I believe T1 shuts off the receiver during transmission to avoid overloading the receiver.

IC1 is a counter that reduces the high frequency crystal clock frequency to the ultrasonic range of the transducers.

IC2 further counts down the signal to give the low frequency pulse rate of the output ping."

N2, N3, & N4 do not need to be Schmitt triggers but the N1 Schmitt trigger (in the same package) is required to prevent oscillations from the slow input signal due to the RC delays at its inputs.
​

 

[Bruce Bullock]

Very interesting, thanks.
1. Why does it need to be crystal controlled vs. a free running 4011 oscillator?

2. Are D3 and D4 acting as a phase detector to get the Doppler shift?

3. Is it sensitive to direction or just rate?

 

[ADWSystems]

There was also this thread where I asked for some help with a high level analysis of the circuit https://www.electro-tech-online.com...el-circuit-analysis-ie-hows-this-work.117358/

It will beep the same no matter what the distance is. It is not a range finder but an object detector set to detect objects within a set distance. I too wonder it would take to convert it to a range finder, if possible.