Hello everyone,

I'm working on an electronics project that uses a flexi force sensor A201 , INA333 instrumentation amplifier and esp32 module ,and I've simulated the circuit using lt1167(in place of ina333), changing the resistance value(in place of sensor) and used behavioural voltage source (in place of adc value conversion on esp32) in LT spice.

However, I'm running into an issue:
when I apply force to the sensor, I observe minimal step variation in mV range in the LT1167's output voltage and no or minimal step variation on bv source values

What I Have Tried So Far :

1.Tried to invoke the ina333 spice models but simulation was not behaving properly.
2. hence used lt1167 built in library ina which is present on ltspice platform.
3. I updated circuit to resolve the issue by adding capacitors to ensure the noise is the problem.
4. Later I checked for the different voltage levels but no change.
5. Later I thought voltage divider may be problem and hence removed it but no effects.
6. also changed r2 value and gain r3 value but it just increased the output voltage swing and bv source value.
7.Also employed the opamp to provide the stable buffer to ref pin.

Are there any circuit modifications or additional components that could help enhance the sensitivity of the circuit?

Any suggestions would be greatly appreciated !

 

Hi rocky,
Welcome to AAC.
Do you have a circuit diagram that you could post?
Perhaps we can use LTSpice to simulate your project?
E

 

Hi rocky,
Welcome to AAC.
Do you have a circuit diagram that you could post?
Perhaps we can use LTSpice to simulate your project?
E

Will send the lt spice simulation

 

lt spice simulation of my project

 

Hi rocky
With the Vsupply at 3.3V and Vref at 1.65V the INA output is saturated at 1.65V

E

 

hi rocky,
Check this option.
E

The INA is not amplifying, I will recheck circuit.

 

hi rocky,
It appears that the INA model is expecting a dual +/-V supply??
E
I will look for the INA333 model and give that a try.

 

Hey eric,
since I need to produce byte force measurement system I need to provide input dc of 3.3 V and that 1 Meg resistance is sensor resistance at 0N force I need to have a device such that it should provide me a necessary output voltage swing and the variation in adc values of esp32 .(which in my case used behavioural voltage source)

 

Hey eric,
since I need to produce byte force measurement system I need to provide input dc of 3.3 V and that 1 Meg resistance is sensor resistance at 0N force I need to have a device such that it should provide me a necessary output voltage swing and the variation in adc values of esp32 .(which in my case used behavioural voltage source)

sir please reply since I am trying to solve from past 3 days

 

hi rocky,
I would say for that application a INA amplifier is not suitable, when using a single supply voltage, have you considered a regular high spec OPA.
BTW: some versions of the ESP32 have a very poor linearity span on their ADC conversions.
E

 

hi rocky,
I would say for that application a INA amplifier is not suitable, when using a single supply voltage, have you considered a regular high spec OPA.
BTW: some versions of the ESP32 have a very poor linearity span on their ADC conversions.
E

Will check about it and thank you so much for suggestion and if any components required can U mention here sir

 

Will check about it and thank you so much for suggestion and if any components required can U mention here sir

I setup by AD8605 opa now ,just the final output voltage swing is increased , still variation in mV range wrt changing resistance which is impossible for adc of esp32 to detect Please reply as soon as possible since I am stuck in this subject sir

 

Hi rocky,
I have downloaded the sensor datasheet, I will check.
E

 

Hi rocky,
I have downloaded the sensor datasheet, I will check.
E

ok sir

 

hi rocky,
The first step was to check their recommended circuit.
I have simulation three plots using 3 different Rinp resistor values, over the range specified in the A201 datasheet.

Can you confirm that the A201 sensor has a linear or logarithmic scaling??

E

 

hi rocky,
Found more info on the sensor, the resistance value is logarithmic.

E
http://www.nexgenergo.com/ergonomics/tekscana201.html

 

hi rocky,
Found more info on the sensor, the resistance value is logarithmic.

E
http://www.nexgenergo.com/ergonomics/tekscana201.html

View attachment 345945

hey eric sir ,Thank you so much for the information of A201 sensor and also I didn't aware of the website u shared it's very useful website
Will look forward for the further information of the existing project and will try to design lot more circuits on future
Once again thank you if found any detailed circuit connections of this project Please send so that I can accelerate the process

 

hi rocky,
Searching for the A201 sensor applications, I found these links, look them over and ask if you have any problems.
The links cover the required calibration.

E
https://www.youtube.com/results?search_query=A201+sensor

 

hi rocky,
Searching for the A201 sensor applications, I found these links, look them over and ask if you have any problems.
The links cover the required calibration.

E
https://www.youtube.com/results?search_query=A201+sensor

Thanks a lot eric sir for these valuable links

 

hi rocky,
Searching for the A201 sensor applications, I found these links, look them over and ask if you have any problems.
The links cover the required calibration.

E
https://www.youtube.com/results?search_query=A201+sensor

hey I designed successfully by using mcp6004 opamp in ltspice where I connected and varied the gain according to my required output whose ouput can be read by esp32 module