| Electronics > Projects, Designs, and Technical Stuff |
| Lever position sensing by Hall effect: switch or analog sensor |
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| Wimberleytech:
--- Quote --- As you can see, this is calling my attention. It would really simplify things as far as sensor placements and mounting. All I would need is to tie one sensor to the rod and place the second one with the MCU. It would be much cleaner than having a circuit board pretty much exposed holding the seven hall sensors! I wonder if a low cost 3 axis accelerometer would provide resolution to discriminate notch positions, which are probably just a few degrees apart. I also wonder about the complexity of the calculations. --- End quote --- I use ADXL345 breakoutboard: https://www.ebay.com/itm/ADXL345-3-Axis-Digital-Acceleration-of-Gravity-Tilt-Module-AVR-ARM-MCU/381374763026?epid=11010018748&hash=item58cbb51012:g:cTsAAOSwKApa8lbz:rk:6:pf:0 Uses I2C communications The code is trivial. Pictures show the guts of the arduino board, and green units are the arduino in one tethered to the ACC in the smaller box. Tractor demo: |
| Back2Volts:
Very cool! And you painted the enclosures John Deere green ! |
| Wimberleytech:
--- Quote from: Back2Volts on January 11, 2019, 06:29:54 pm ---Very cool! And you painted the enclosures John Deere green ! --- End quote --- 3D printed with green filament!! |
| Back2Volts:
--- Quote from: soldar on January 11, 2019, 05:56:44 pm --- --- Quote from: Back2Volts on January 09, 2019, 11:47:16 pm --- I believe, using the digital switch will result in a simpler GPIO design, but my concern is that the sensor may not get turned on at 20mm distance. --- End quote --- Or you could have the problem that the magnet activates more than one sensor. --- Quote ---I had not thought of that. It will be fairly easy to test on breadboard. --- Quote ---I would look into the very simplest and most reliable linear transducer and then take the signal to the ADC and electronics which are well protected and out of the way. --- End quote --- My gut feeling is that this will be the way to go (if the accelerometer idea does not win) --- Quote ---You say it moves a steel cable. Like a Bowden cable like the brakes of a bicycle? If the tension on the cable and the sheave is proportional to the position then it should not be difficult to get a transducer that measures that force. If there is no appreciable change in force on the cable then you could put a spring to any moving part and the spring would provide a variable force. You can make a transducer quite simply with double sided PCB so that when it flexes the strips on one side stretch and increase resistance and the strips on the other side shorten and decrease resistance. A Wheatstone bridge and an OpAmp and you have your transducer. --- End quote --- The existing steel cable has been giving me problems. The goal of this project, is to take cable out of picture. That said, the idea of hooking a spring with load cell is worth exploring... --- End quote --- --- End quote --- |
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