Linear Position Sensor - typical use

------Question for 20LHE1AWA1P30 Please Put your question below------
Hi Team,

I am writing to enquire if the product (Part no. 716-1046-ND) provides for the longitudinal movement of the 3mm shaft.

My understanding is that it does, given that the specification mentions a 0 to 10 mm electrical stroke.

Can I ask for a confirmation on this? I intend to use the product to measure longitudinal displacement of the target (moving metal component), which is estimated to be about 5 to 7mm. The product’s 3mm shaft would be in contact with the target when assembled.

It would help me immensely if I could get a confirmation on this before I procure them. This is my first time handling sensors :slightly_smiling_face:

Thanks for your time
GG

Hello @g.s.garge,

Yes, the Vishay Sfernice 20LHE1AWA1P30 sensor will detect linear motion from 1 to 10 mm. Note that the selected part is spring loaded to make contact with workpiece / machine. as shown in this highlighted except from the datasheet.

Note that the product has a ratiometric output. This implies that the output will be a percentage of the power supply. This is good news if you are using a 5 VDC microcontroller such as the Arduino Nano Every. Here we can use the default " 5 VDC rail" as the reference for the Arduino’s analog to digital converter. We then power the sensor from the same voltage rail. Now, when, not if, the rail voltage changes, both the ADC and the sensor move in unison. The result is a system largely immune to variations in supply voltage.

Kindly tell us more about your project, pictures are especially welcomed. Also, please let us know if this has answered your questions.

Best Wishes,

APDahlen

P.S. Note the fully exteded shaft length is 30 mm.

Hi Dahlen,

Thank you so much for the immediate response.

Yes, I have noted that the extended shaft length is 30 mm. I’ve noted the highlighted aspects of the ordering information as well as the use with Arduino. I suspect we would be using Raspberry Pis since we have them in our lab.

I would be keen to know if there are other brands of sensors - similar functionality and linear range to the 20LHE - which are available with yourselves. Would appreciate any suggestions you might have.

Thanks!
GG
The sensor would be used in an initial feasibility study which would become a part of something larger - not fully mentioned at this point.

Hi @g.s.garge,

Watch out for the power supply requirements.

The sensor requires 5 VDC. As I recall, the Pi has 3.3 VDC and requires an external ADC:

  • The Arduino Nano Every could fulfill both requirements, although you still need a way to get the data back to the pi that will accommodate the 5 VDC to 3.3 VDC issue.

  • With respect to the external ADC, you could select a device with a 5 VDC power supply and a I^2C interface. Power the device with 5 VDC to take advantage of the sensor’s ratiometric properties. For the communications, use pull up resistors to the 3.3 VDC I/O.

DigiKey has a variety of sensors. It’s no easy task to select the “best” device for you application. For example, a sensor such as this could be used. However, we must consider the life of a resistive element when compared to your original Vishey non-contact Hall device. We also need to consider the system level implementation with power supply and ADC.

Depending on your application, a simple limit switch could do the trick. For example, suppose you use a stepper motor such as this, rather than measuring position with a sensor, you could infer position by counting the number of steps required to activate the switch pressed up against your workpiece. Perhaps your mechanism already has such a motor installed.

Good luck on your project. We hope to hear from you again.

Sincerely,

Aaron

Hi Dahlen/Aaron,

Thank you indeed for the very relevant inputs you have provided.

I believe I now have a range of devices that I can experiment with to establish the functionality. Of course, the end use will dictate the choice of the appropriate sensing technology. Your suggestions will hep me demonstrate the required functionality over a range of sensors available.

Thank you so much. I shall initiate the procurement process.

Regards,
GG

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