pictographer
Well-known member
What do you think of using an ADSL filter to protect Teensy 3.1 I/Os from a photodiode connected to a 2 meter cable?
I understand this will filter out the high frequencies. I don't really understand the implications of applying the filter designed for 48V to a lower voltage signal. I'm guessing it won't hurt anything, but might obliterate the signal entirely.
I'm working on a very simple Teensy 3.1 data acquisition system intended to help with basic Physics lab experiments. I'm planning for the sensors to be connected to unshielded two conductor stranded phone cord about 2 meters long. From this article Protecting Inputs in Digital Electronics I see some of the bad stuff that can happen when microprocessor I/Os aren't protected, but I don't have a way of measuring subtle damage or monitoring the signals to see voltage undershoot, ESD spikes, etc.
At this stage, I'm not attempting to make something that will take years of harsh environment abuse and I'm inclined to start with something fast, cheap, and easy. I'm just trying to make a working prototype and learn what I can along the way. I'm not sure how far to go. For now, I'm using a 200Ω resistor in series with the analog input. Some of the protection circuits get pretty elaborate, but I'm not expecting to make something that will survive a lightening strike...
I understand this will filter out the high frequencies. I don't really understand the implications of applying the filter designed for 48V to a lower voltage signal. I'm guessing it won't hurt anything, but might obliterate the signal entirely.
I'm working on a very simple Teensy 3.1 data acquisition system intended to help with basic Physics lab experiments. I'm planning for the sensors to be connected to unshielded two conductor stranded phone cord about 2 meters long. From this article Protecting Inputs in Digital Electronics I see some of the bad stuff that can happen when microprocessor I/Os aren't protected, but I don't have a way of measuring subtle damage or monitoring the signals to see voltage undershoot, ESD spikes, etc.
At this stage, I'm not attempting to make something that will take years of harsh environment abuse and I'm inclined to start with something fast, cheap, and easy. I'm just trying to make a working prototype and learn what I can along the way. I'm not sure how far to go. For now, I'm using a 200Ω resistor in series with the analog input. Some of the protection circuits get pretty elaborate, but I'm not expecting to make something that will survive a lightening strike...