But any of those would eliminate his idea of "being gravity driven". The same as his original use of a pot.For accuracy, i was going to suggest scales that are used to retrofit machine shop tools. See: http://www.dropros.com/DRO_PROS_Digital_Readout_Scale.htm
An LVDT sensor is probably more robust: http://www.omega.com/subsection/dc-lvdt-sensors.html
First time I've seen one of those! ... Here's another one with bluetooth output that he could use to interface it to his phone. It would make it the hell of a lot easier to generate a log.I thought at first of a electronic laser measure but the crop may give a false reading, so could you attach one of these at all where the tape can be carried down with the rod?
https://www.amazon.ca/eTape16-ET16-...63971&sr=8-1&keywords=electronic+tape+measure
Max.
That's what I was picturing as well. Perfect application for an inductance or LVDT measurement. As I mentioned earlier, the LDC1000 is worth looking into. I have played with the LDC1000-EVM and done exactly this. It is one of my projects on the back burner. I have a 3' piece of PVC with wire tightly spiraled around it, and as i slide a steel rod thru the tube, the inductance changes wildly. With 32 bit resolution you can get a gnat's ass position from it."the tube is attached to a plate which sits on the crop, the rod goes through the crop touches the ground, when you lift it up the pins slides out to full travel."
What "pins"? Can you post a sketch with this detail.
So, it is a form of a penetrometer.
View attachment 129962
Ken
I would've thought that 24 bits would be fare more than enough, but I'd really like to see 32 bit resolution for this application.That's what I was picturing as well. Perfect application for an inductance or LVDT measurement. As I mentioned earlier, the LDC1000 is worth looking into. I have played with the LDC1000-EVM and done exactly this. It is one of my projects on the back burner. I have a 3' piece of PVC with wire tightly spiraled around it, and as i slide a steel rod thru the tube, the inductance changes wildly. With 32 bit resolution you can get a gnat's ass position from it.
12 bits = 4,095 divisions = 0.07326 mm/div
16 bits = 65,535 divisions = 0.00458 mm/div
24 bits = 16,777,215 divisions = 0.0000178814 mm/div
32 bits = 4,294,967,293 divisions = 0.000000069849 mm/div
My memory was off. I thought it only came in 32 bit version; actually There is no 32 bit version. There's 12bit and 28 bit. yeah 12bit should be fine.I would've thought that 24 bits would be fare more than enough, but I'd really like to see 32 bit resolution for this application.
If travel distance is set at 300 mm, then think of this:
Wouldn't you say that 12 bits would be far more than enough for this application?Code:12 bits = 4,095 divisions = 0.07326 mm/div 16 bits = 65,535 divisions = 0.00458 mm/div 24 bits = 16,777,215 divisions = 0.0000178814 mm/div 32 bits = 4,294,967,293 divisions = 0.000000069849 mm/div
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