Hi demi,
Yes use that LM393 as the comparator, don't forget to add some hysteresis to the comp.
E

 

Really, this is simulating the operation of a system used to monitor the position of the ram in hydraulic cylinders. We had a "go-around" with that function a few years back. The capacitor for timing the receive-enable was a bit deffective in the production run units we received. THAT caused a few serious problems.

 

Really, this is simulating the operation of a system used to monitor the position of the ram in hydraulic cylinders. We had a "go-around" with that function a few years back. The capacitor for timing the receive-enable was a bit deffective in the production run units we received. THAT caused a few serious problems.

why is that sir can you explain a bit , it may helps me one day.

 

why is that sir can you explain a bit , it may helps me one day.

That system sends a magnetic pulse down a steel rod, and when the pulse passes a magnet it sens an electrical pulse back up the rod. So the time difference indicates the distance traveled. The actual scheme is proprietary.

 

That system sends a magnetic pulse down a steel rod, and when the pulse passes a magnet it sens an electrical pulse back up the rod. So the time difference indicates the distance traveled. The actual scheme is proprietary.

So may it is because the magnetic field or electric field effects upon the cap ?

 

I could not test the comparator builts yet btw whenever I do I will upload

 

I did the tests , Lf353 opamp is not good at giving output unless input exceeds the vref too much.
I currently try to use lm393 but it does not work as sim.

 

I did it. Finally working

 

Hi demi,
This simulation shows a stepped [V2] Echo from 1mSec to 9mSEc, with a 10mV echo amplitude.
Experiment using echoes signals of different magnitude.
I have used a LM393 in place of the LM2903, it will not change the operation of the circuit.

The swept TGC need a little more work.

E

 

hi demi,
Run this simulation, it is slow as it steps the echo amplitude from 1mV to 10mV at 1mSec intervals from 1mSec to 9mSec.
Note the error output signal on Vout
E

 

Hi Eric , I see that the error is due to offset exceeds the vref earlier than excepted as I see.
I used an potensiometer to make Vref adjustable. In experiment , this issue did not appear. Is there still a problem ?
Also , when I use a lower resistor at the output of comparator , the input signal breaks why is that sir ?

 

The only problem is when I set vref a bit more higher , I can start measurement from 30cm but the final signal disappears earlier.
Rc adjustment can solve this I guess.

 

Hi demi,
Usually, when using a Comparator, some level of Hysteresis is added from the Output to the Non Inverting input. ie; positive feedback via a high value resistor.

How do you plan to use the output pulse?

If it is being detected by an MCU input, all that you are interested in , is the first rising edge of the pulse.

Hint: If you reduce R5 to say 20k, it will reduce the Vout pulse to ~+5V max
Added: and change VDD on R18 to VGND
E

Added a PDF.

 

Hi demi,
Usually, when using a Comparator, some level of Hysteresis is added from the Output to the Non Inverting input. ie; positive feedback via a high value resistor.

How do you plan to use the output pulse?

If it is being detected by an MCU input, all that you are interested in , is the first rising edge of the pulse.

Hint: If you reduce R5 to say 20k, it will reduce the Vout pulse to ~+5V max
Added: and change VDD on R18 to VGND
E

Added a PDF.

I do plan to detect it using mcu input.

 

hi,
Are you going to use a high going Pin Interrupt?


E

 

hi,
Are you going to use a high going Pin Interrupt?


E

Hi , I do know interupt system that I used in stm32 before but I haven't used in arduino yet. I may code an alrogithm that uses digital real rapidly Idk.
The algorithm in my plan is , after the transmit process , setting the active function to waitecho and check for high voltage rapidly.

 

Hi demi,
When you have written the Arduino Sketch, post it and I can run a check on my system.
E

 

Hi demi,
When you have written the Arduino Sketch, post it and I can run a check on my system.
E

Okay sir I will upload when I process.

 

I've tried it but when I connect the zener setup at the output of comparator , output keeps it's shape but it is under 2v peak pulses.
I guess in case I use an buffer this problem solves but I am using many components and wonder if I do sometging wrong.

 

Hi , I use this code to send pulse and then detect the echo pulse but arduino does not detect those returning pulses.
Yellow traces are the comparator output , blue ones are the biased and amplified signal.
Btw it may not be the best way of limiting output voltage but I connected a zener diode between comparator output and gnd.