Welcome to EnviroDIY, a community for do-it-yourself environmental science and monitoring. EnviroDIY is part of WikiWatershed, a web toolkit designed to help citizens, conservation practitioners, municipal decision-makers, researchers, educators, and students advance knowledge and stewardship of fresh water. New to EnviroDIY? Start here

Reply To: Hydros 21/Decagon CTD: reading error

Home Forums Environmental Sensors Hydros 21/Decagon CTD: reading error Reply To: Hydros 21/Decagon CTD: reading error


We wrote Program for Interfacing Hydros sensor 21 with Arduino Uno board using SDI-12 interface and saw the result on serial monitor . We tried a lot in implementing a program for connecting sensor directly to the digital Pin (Pin7/Pin2) of the Arduino UNO board using SDI-12 interface and viewing the result on the serial monitor. We found only garbage data coming on the serial Monitor.

We uploaded program here.

#include <SDI12.h>

const int dataPin = 2; // Connect the data pin to digital pin 2
SDI12 sdi12;

void setup() {

void loop() {
// Request data from the sensor

// Wait for the sensor to respond

// Read and print the sensor response
while (sdi12.available()) {
char c = sdi12.read();

// Wait for a moment before taking the next reading

Can you guide whether we require any digital hardware between Hydros sensor21 and Arduino Uno board?