Author Topic: "Mechanical" servo driven gauge, proof of concept  (Read 604 times)

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Offline SLOweather

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"Mechanical" servo driven gauge, proof of concept
« on: March 10, 2016, 04:43:53 PM »
Awhile back, I postulated about using rc servos as drivers to simulate mechanical gauges or meters.

Yesterday, the final piece of this particular puzzle arrived from China, some 0-5 volt servo controller boards.

I have my bench Rugid Computers RUG9 controller programmed to read an LM34 temperature sensor and output it as a scaled 4-20 ma 30-90 degree signal. There is a 220 ohm load resistor to create the voltage, across which I have the 0-5 volt servo board connected, and a micro servo connected to that.

After I made sure it all functioned, I found a random meter face on the net, printed it and glued it to a piece of cardboard and cut it out. The servo is mounted behind it. The hand or needle is a black zip tie.

Here is a video of the first test run. It's not calibrated, and the one "undocumented feature" is that the servo works backwards (higher temperature/control voltage = counterclockwise rotation). I can fix that in programming. I stuck my home made probe alternately in hot water and ice water.

BTW, the servo below the dial face is controlled similarly by a Davis anemometer. Unfortunately, the wind was calm when I did the video.


https://youtu.be/qM1SzYCl5J8
« Last Edit: March 10, 2016, 04:45:34 PM by SLOweather »

Offline Bushman

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Re: "Mechanical" servo driven gauge, proof of concept
« Reply #1 on: March 10, 2016, 04:57:43 PM »
This would be  a snap with a Raspberry Pi!

Offline SLOweather

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Re: "Mechanical" servo driven gauge, proof of concept
« Reply #2 on: March 10, 2016, 05:09:05 PM »
This would be  a snap with a Raspberry Pi!

Or an Arduino, or even a Basic Stamp 2. And I could have done the 0-5 volt interface with a Stamp or even a 555. I have personal reasons for using the RUG9, and I find that, at this point, I prefer the "black box" approach over the component level work.

 

anything