Show Posts

This section allows you to view all posts made by this member. Note that you can only see posts made in areas you currently have access to.


Messages - paulse

Pages: [1]
1
Thank you for the clarification, Borg.

Does SHARP provide a more in depth calibration curve than Fig.2 in http://www.sharp.co.jp/products/device/doc/opto/gp2y0a21yk_e.pdf ?

Something that indicates some sort of noise within the signal?  Say, something to quantify the precision and accuracy as detailed in the diagram below?
 
https://meettechniek.info/measurement/accuracy-images/definitions.gif

How is the digital signal converted to displacement?  Or is this all a black box that is only minorly detailed in the block diagram as the "signal processing circuit" of the PSD?


2
Hello,

I see that the tinkerforge uses an ADC (12 bit range: Not Disclosed) converter on the IR distance sensor.  This seems to be a poor match with the performance specs on the sensor (http://www.sharp.co.jp/products/device/doc/opto/gp2y0a21yk_e.pdf).  Has anyone used a better ADC with this product?  eg.

For a 0-5 V ADC at 16 bit:
  • resolution = 5/2^16 ​​ V/bit = 7.6 x 10-5​​ V/bit
  • linear range of IR sensor document (i.e. 100 mm to 500 mm) =  50 mm / 1.55 V = 32.2 mm/V
  • so for 0-5V 16bit resolution ADC: the resolution should be 2.46 x 10-3​​ mm/bit

From this calculation the current resolution seems poor (maybe because tinkerforge is trying to save money and not concerned to much with resolution).  Even with a  0-5 V ADC at 12 bit resolution: (0.0407 mm/bit) 

Has anyone used a different ADC with the IR displacement sensor?

Thanks in advance,
Paul

3
General Discussion / Re: Set sampling frequency on MasterBrick
« on: March 05, 2018, 21:21:42 »
Thank you kindly, Bernhard.

Having I am trying to visualize it in real time in Matlab and it seems like MATLAB is bottlenecking how fast real-time reading can be done.  I will try to use a call function and store the faster sampled data (using the callback function) separately.

I've attached the MATLAB script if you are interested.  The main part that slows down the acquisition (and thus storage of data) in this script is the "draw now" function.  I have recently made a GUI that uses this code as the base and allows me to stop and save the data to a specified file but I would like higher sampling rates with a callback function and seperate storage location, I hope.

Thanks,
Paul

4
General Discussion / Set sampling frequency on MasterBrick
« on: March 01, 2018, 17:51:28 »
Can someone help me set a higher sampling frequency on the Master brick?

I am currently running a Load cell bricklet and IR displacement sensor bricklet.  Is there a software call function that does this?  I am interacting with the MasterBrick using Matlab.

Thank you kindly

5
General Discussion / FS5113R at constant velocity
« on: February 28, 2018, 16:01:13 »
Can you trick the servo brick and FS5113R motor to just rotate at a constant angular velocity?

6
General Discussion / SERVO Brick stop recognizing my two bricklets
« on: January 25, 2018, 15:48:51 »
Hi,

I had my Servo Brick working and I was using the Distance IR and Load Cell Bricklets with it.   It was working fine (interfacing through matlab and was reading out value in real-time) then it suddenly stopped working.  By stopped working I mean only the Servo Brick registers when nothing is connected to the bricklet ports.  As soon as I connect to the bricklet ports and reset the Servo Brick, nothing is registered in the "add device" section of Brick Viewer.

Any suggestions to get my Birck working again?  I'm using a 5.2 V 0.5A DC power supply and I can operate a small motor with the servo.  May it have to do with the erase button?  did I erase some of the on device firmware?

Pages: [1]