Amplify Position Sensor Circuit

In summary, the sensor is functional but the data logger available to measure it can only measure at a resolution of 5 values and this is not good enough to demonstrate damping trends. The solution lies in amplifying the voltage signal from the sensor.
  • #1
CameronRose
12
1
Hi everyone,

I'm working on a college project this year about mountain bike suspension damping. By trade I'm a mechanical engineer however, I'm required to construct a simple sensor circuit to monitor the performance of the damper I am making. Forgive me if my wording or logic is not quite correct on certain aspects.

I picked up a sliding potentiometer to use as a sensor since it was astronomically cheaper than inductive or other resistive options. The system has to be entirely stand-alone since, it will be tested in real world environments. I decided to connect the potentiometer in series with a standard 1.5V AA battery and a 150K resistor since the current rating on the pot is <10uA. As far as observation with a multimeter goes, this is functional. However, the stand-alone voltage data logger I own can only record in increments of 0.01V, this is an issue since the potentiometer voltage ranges between 0 and 0.05V which would only allow me ever to (optimistically) record 5 different values. Not nearly a good enough resolution to demonstrate damping trends.

I believe the solution lies in amplifying the voltage signal from the sensor however, I haven't a clue where to start when it comes to choosing an amplifier and I am even less familiar with how I would go about wiring one to do the required task.

Specifications
Potentiometer - 5K Ohms, <10uA, 200mm travel
Data Logger - 0-32V in increments of 0.01V, USB interface, 400Hz recording speed

Any input would be greatly appreciated!

Cameron.
 
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  • #2
Are you sure the current rating is <10uA? That sounds kind of small. What is the part number on that?

BoB
 
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  • #3
I'm beginning to doubt the validity of the manufacturer's spec sheet, it was also remarked by someone on another forum that it seemed like an unusually low rating. There is mention of 20mA further down but it's unclear what this represents.
 
  • #4
CameronRose said:
I'm beginning to doubt the validity of the manufacturer's spec sheet, it was also remarked by someone on another forum that it seemed like an unusually low rating. There is mention of 20mA further down but it's unclear what this represents.

doesn't help when all the spec's are in Chinese ( even after switching to English)
 
  • #5
I suppose that's the price I'm paying for ordering a cheap generic one from China :H

I had to download Google Translate onto my phone and then use the inbuilt OCR software to translate the spec sheet.

Translations of the relevant parts are as follows.

"Current Recommended (uA) - 10"

Then further down (as best the app can manage):

"It can also be converted to a 4 ~ 20mA DC current signal"

Haven't got any data acquisition gismos available so I decided to chance it and hook it up to a 9V battery and 30K resistor, running with a steady voltage across it so far so I think I'll assume that the 10uA is related to something else.
 
  • #6
Power = Volts2 / Resistance
I'd put 5 volts across it. That's 52/5000 = 1/200th of a watt.
As rbelli hinted, If it's too flimsy to handle that it's useless.

However - because it can take 5 volts end to end does NOT mean it can take 5 volts from its variable terminal to an end.
Identify the terminals using your multimeter.

05149.png


Probably you'll be okay powering it from your logger's 5 volt supply.
 
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  • #7
Since the sensor is a film resistance element, that 10uA is almost certainly the wiper current rating.
 

Related to Amplify Position Sensor Circuit

What is an Amplify Position Sensor Circuit?

An Amplify Position Sensor Circuit is a type of sensor circuit used to accurately measure the position of an object. It typically consists of a sensor, amplifier, and output circuit.

How does an Amplify Position Sensor Circuit work?

The sensor in an Amplify Position Sensor Circuit detects changes in position and converts them into an electrical signal. The amplifier then increases the strength of this signal, and the output circuit translates it into a usable form, such as a voltage or current reading.

What are the advantages of using an Amplify Position Sensor Circuit?

Amplify Position Sensor Circuits offer high accuracy and sensitivity, making them ideal for precise position measurements. They are also relatively simple to use and can be easily integrated into electronic systems.

What are some common applications of Amplify Position Sensor Circuits?

Amplify Position Sensor Circuits are commonly used in robotics, motion control systems, and industrial automation. They can also be found in automotive applications, such as throttle position sensors and steering angle sensors.

How do I choose the right Amplify Position Sensor Circuit for my application?

The most important factors to consider when choosing an Amplify Position Sensor Circuit are the range and resolution required for your specific application. You should also consider the type of output signal and the environmental conditions in which the sensor will be used.

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