Hello,
I have 2x sensors that come from the manufacture with a stereo phono plug at the end.
Sensor #1: Tip is power (3.3V), ring is analog signal (0 to 3.3V representing sensor reading), and sleeve is ground.
Sensor #2: Tip is power (12V), ring is digital signal (0 to 3.3V), and sleeve is ground.
The problem I am facing is that when you insert the sensor into the port, the tip of the phono plug will momentarily make a connection between the tip (power) and the ring(data). This is not an issue with the 3.3V power, but if using 12V power this sends 12V into the microcontroller which is bad. What is a good way of accommodating this?
Here is my circuit currently:
Also, I have some phono receptacles that have the 2x switches inside... however, the short circuit occurs before the switches are open, and still occurs temporarily even after the switches have opened... so I'm not sure how useful it will be to utilize the phono receptacle switches?
Here is the sequence:
Thanks and any help or advice is greatly appreciated!
I have 2x sensors that come from the manufacture with a stereo phono plug at the end.
Sensor #1: Tip is power (3.3V), ring is analog signal (0 to 3.3V representing sensor reading), and sleeve is ground.
Sensor #2: Tip is power (12V), ring is digital signal (0 to 3.3V), and sleeve is ground.
The problem I am facing is that when you insert the sensor into the port, the tip of the phono plug will momentarily make a connection between the tip (power) and the ring(data). This is not an issue with the 3.3V power, but if using 12V power this sends 12V into the microcontroller which is bad. What is a good way of accommodating this?
Here is my circuit currently:
- The 33 ohm resistor is there to protect the power when it gets short circuit temporarily when plugging the phono plug in (draws 0.1 amp when shorted to ground).
- I need the microcontroller to have control of giving power to the sensor, so I put a transistor on the ground pin of the phono plug, is this an acceptable way of accomplishing this?
- The 200k ohm pull-down resistor is there so that when no sensor is plugged in, the reading is 0 (ground). This seems to be such a high resistance that it doesn't effect the sensors analog-output, or the sensors digital-output.
Also, I have some phono receptacles that have the 2x switches inside... however, the short circuit occurs before the switches are open, and still occurs temporarily even after the switches have opened... so I'm not sure how useful it will be to utilize the phono receptacle switches?
Here is the sequence:
Thanks and any help or advice is greatly appreciated!