Hex 2 Posted September 4, 2013 Share Posted September 4, 2013 anyone used a continuous rotation resistor for a dc motor for tracking position like this one from digikey: http://www.digikey.com/product-detail/en/3382G-1-103G/3382G-1-103GTR-ND/1944266 manufacturer is Bourns. I need to track rotation of motor, to linear motion, like a lead screw. motor is 6v, ~1500rpm. only need to track about 20 revolutions in either direction. anyone have any other cheap suggestions, that are relatively small in size. Quote Link to post Share on other sites
RobG 1,892 Posted September 4, 2013 Share Posted September 4, 2013 How about rotary encoder? Quote Link to post Share on other sites
veryalive 49 Posted September 4, 2013 Share Posted September 4, 2013 - how about a linear potentiometer, also called a 'slider pot' from an audio system, with the wiper attached to the linear-motion portion of your solution. - then you measure the analog voltage at the slider - this then tells you how much linear motion your actuator has undergone. then control the motor direction in your software. - so, in the diagram below: linear actuator full left would give the highest AtoD value; full right would give the lowest value. MOTOR -----> | Linear actuator = Lead screw | ^ | --- (knob) ------------------------------- | Slider potentiometer | ------------------------------------------ | | | V+ | Gnd | To 430 AtoD cheers. Quote Link to post Share on other sites
JWoodrell 285 Posted September 4, 2013 Share Posted September 4, 2013 if you can fix a magnet to the shaft a magnetic sensing IC will give you very good accuracy absolute position readings up to high RPM I have used an AS5132 which gives 360 counts / revolution at speeds up to 72.9K RPM but there are the AS5140H (10 bit count per revolution = 1024 counts / revolution at speeds up to 10k RPM) and AS5048B (14 bit counts per revolution = 16384 counts / revolution with a sample rate of 11kHz (doesn't list an RPM)) as well pricewise AS5132 = $5.50 AS5140 = $10 AS5048 = $11 prices from mouser. the magnet is about a 40 cents or so link (diametrically magnetized) at least with the AS5132 which i have used... if you are talking to it serially, it has a 9 bit multi turn counter internally (+- 256 turns) that you can read as well as the position within the current revolution to give you the full count of its position so you don't have to keep up with it yourself. and the current position (within the current turn) can be read out as a pwm signal, as serial data, and or as a pulse train depending on what you are reading it with. Quote Link to post Share on other sites
abecedarian 330 Posted September 5, 2013 Share Posted September 5, 2013 ams.com will often send samples of their rotary encoders. JWoodrell 1 Quote Link to post Share on other sites
Lgbeno 189 Posted September 7, 2013 Share Posted September 7, 2013 +1 for the AMS magnetic encoders Quote Link to post Share on other sites
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