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teensy 3.2 with 5v flex sensors
This is probably a beyond noob question but I'm working on a project that uses flex sensors that require 5 volts and I want to use them with a teensy 3.2 If I'm reading correctly, the teensy analog inputs only tolerate 3.2 volts. I can obviously power the sensors from my breadboard power supply but what do I do with the control voltage? (I've already got a 10K resistor in line, but when I tried to send a signal to the Teensy post-resistor I got bogus results (and maybe fried my teensy?)
You need a voltage divider. Something like 2k from the flex output and 3k to ground. Tie the 2k, 3k junction to the analog input. Multiply that value by 1.66 to correct for the voltage division as your 0 to 5v signal will be scaled to 0 to 3v by the divider. You may need a buffer if there is a large distance between the sensor divider and the analog pin, but beware of other problems that may arise if the buffer input floats and your are using more than 3v as a power source for it.