Constantin
Well-known member
So I am considering the use of a DS18B20 one-wire temp sensor with a Teensy 3.1. There are many ways to power the sensor and the attendant tradeoffs. The sensor can operate with a power supply from 3-5.5VDC. Due to its location, using 5VDC would be advantageous (very short line to power) while there are also other options (like powering it from the Teensy by pulling a pin high). The maximum power dray of a DS18B20 is 4mA, i.e. within spec for the amount of power a digital pin can supply.
What I wonder about is which approach is best, from a long-term, happiness point of view on the MK20 chip on the Teensy 3.1 itself. Would the MK20 be happier supplying power and having all logic levels for the DS18B20 run at around 3.3V or is having 5V signals on a digital pin preferable?
What if the 5V signal (coming raw from a wall wart, USB bus, etc.) wobbles, as they are wont to? I see that I'm talking myself into a 3.3V-only solution but wonder if the parasitic or two-pin option (i.e. one supplying power, the other communicating with the MK20) is viable and/or preferable.
I expect any of these approaches to work, what I want to ensure is that the Teensy 3.1 chip life expectancy is maximized.
What I wonder about is which approach is best, from a long-term, happiness point of view on the MK20 chip on the Teensy 3.1 itself. Would the MK20 be happier supplying power and having all logic levels for the DS18B20 run at around 3.3V or is having 5V signals on a digital pin preferable?
What if the 5V signal (coming raw from a wall wart, USB bus, etc.) wobbles, as they are wont to? I see that I'm talking myself into a 3.3V-only solution but wonder if the parasitic or two-pin option (i.e. one supplying power, the other communicating with the MK20) is viable and/or preferable.
I expect any of these approaches to work, what I want to ensure is that the Teensy 3.1 chip life expectancy is maximized.