i have an issue in programming .i have a sensor which is hydros21 sensor which work on sdi12 protocol but in my case this sensor is not working with arduino uno .can any one solve the issue by arduino coding.
@prvr ,
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Thank you
All SDI-12 communications are transmitted in ASCII at 1200 baud with 7 data bits and an even parity bit. From:
Edit: What serial port do you plan on using? Hardware or software?
It's a 5v digital interface.
How do you know?
If it’s really not working, throw it away and buy a new one.
Perhaps it’s ok, but your circuit has a problem..?
Please post ‘how’ you determined irs ‘ not working’
Post anny existing code (in CODE tags), and showing us your schematic will help, we can ask more questions later.
We were getting data from sensor conductivity, Water Level and Temperature but now it stopped giving data. We checked with power (from 5v to 12v) both external and internal. Also we connected pull up resistor (10k ) in the power line and Pull down resistor 100k in the ground. but there was no response.
Earlier too, sometimes data was not coming; it was coming when we were touching it with our hands.
Please guide us.
Hi, @prvr
Please post your code. using code tags.
Can you please post a copy of your circuit, a picture of a hand drawn circuit in jpg, png?
Hand drawn and photographed is perfectly acceptable.
Please include ALL hardware, power supplies, component names and pin labels.
Can you please post some images of your project?
So we can see your component layout.
Do you have a DMM? Digital MultiMeter?
Thanks.. Tom... 
We were getting data from sensor conductivity, Water Level and Temperature but now it stopped giving data. We checked with power (from 5v to 12v) both external and internal. Also we connected pull up resistor (10k ) in the power line and Pull down resistor 100k in the ground. but there was no response.
Earlier too, sometimes data was not coming; it was coming when we were touching it with our hands.
Please guide us.
You have a mistake on line 57. Should be X>3