I have a sensor which constantly outputs serial data at very low voltages (in the milli-volt range), however I need to read this serial data using a PIC micro controller. How can i convert this data to logic level using basic components.

All solutions i have read so far are for bi-directional communication and require a specialized chip. For my purposes I simply require uni-directional communication, and would prefer used basic components available at any electronics stores.

  • \$\begingroup\$ how do you know the sensor gives PWM out \$\endgroup\$
    – Lokanath
    Sep 16, 2015 at 4:22
  • \$\begingroup\$ If it is low frequency output, try connecting a MOSFET gate to sensor output and drain with a pull-up resistor to your pic MCU. \$\endgroup\$
    – AKR
    Sep 16, 2015 at 4:36
  • \$\begingroup\$ @Lokanath its based on my oscilloscope reading \$\endgroup\$ Sep 16, 2015 at 5:03
  • 1
    \$\begingroup\$ do you have sensor part no,,data sheet?? \$\endgroup\$
    – Lokanath
    Sep 16, 2015 at 5:08
  • \$\begingroup\$ unfortunately no part number is available \$\endgroup\$ Sep 16, 2015 at 5:41

1 Answer 1


Base on the oscilloscope's response you can't be sure of the actual protocol of the sensor and you should watch up the sensor's datasheet. The sensor can be analog or its output can be based on current and not voltage in the case you can use any kind of current sensor or many other techniques.

It is hard to offer the exact answers to the question due to lack of information. Any way there are several techniques which you can use to fulfill your purpose regarding to the relative frequency and variation of the voltages. First you can use the micro's ADC of course if the frequency is low enough. Also you can use transistor or high slew rate op-amp to read your signals. If you determined the signal's frequency and its voltage variation (if there is any) and the sensor's output's type, there could be more available answers.


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