Reading NMEA out data from Humminbird Helix 7
Posted: Tue Apr 21, 2020 2:13 am
So far I’ve established connection with my NodeMCU 8266 and Navionics Boating App. I achieved this by sending dummy NMEA depth data. As a next step I need to get my Helix 7 unit connected with ESP8266 so that I can read what it is sending out. With Google is was pretty easy task to find this pinout diagram and looking at the back of my device I can confirm that there is a similar connector and only 3 of the female holes are showing any copper so I think I’ve found the right diagram. I was a bit disappointed not to find +12v pin since that would have allowed me to get power for my ESP8266 using a DC voltage dropper. Well I can always power my device from any other +12v wires on my boat.
http://forums.sideimagingsoft.com
Before I would be able to read any NMEA data from Helix 7 we need to turn on NMEA transmission from the unit. That is done by selecting menu button twice on my Helix unit -> settings -> turn NMEA on. Now that I know which of the pins is sending NMEA out and I know the ground pin as well, I took my multimeter, set it on DC and tried to read the voltage. It was jumping up and down as expected on the serial signal. So tweaked my multimeter a bit to capture max voltage. I was able to see max 3.0V. Repeated couple of times and was not able to capture anything above that. Since signal voltage is not above 3.0V I assumed that it’s safe to connect signal directly to ESP8266 since it’s running on 3.3V.
I really had hard time getting my head around all the different wiring diagrams that I found when trying to understand what needs to connect and where. So, I ended up making this diagram to document what I did. Powering my board from my boats USB charger.
I then tried using this code to read what my unit was sending.
I was expecting NMEA sentences but to my surprise I was seeing just numbers coming out from by Helix 7 unit. Mostly 3-digit numbers but sometimes also 2-digit or single digit. I think I’ve hit a wall. I have no idea what these numbers are or how to treat this data. Would someone have any idea?
http://forums.sideimagingsoft.com
Before I would be able to read any NMEA data from Helix 7 we need to turn on NMEA transmission from the unit. That is done by selecting menu button twice on my Helix unit -> settings -> turn NMEA on. Now that I know which of the pins is sending NMEA out and I know the ground pin as well, I took my multimeter, set it on DC and tried to read the voltage. It was jumping up and down as expected on the serial signal. So tweaked my multimeter a bit to capture max voltage. I was able to see max 3.0V. Repeated couple of times and was not able to capture anything above that. Since signal voltage is not above 3.0V I assumed that it’s safe to connect signal directly to ESP8266 since it’s running on 3.3V.
I really had hard time getting my head around all the different wiring diagrams that I found when trying to understand what needs to connect and where. So, I ended up making this diagram to document what I did. Powering my board from my boats USB charger.
I then tried using this code to read what my unit was sending.
Code: Select all
int data; //Initialized variable to store received data
void setup() {
//Serial Begin at 4800 Baud
Serial.begin(4800);
}
void loop() {
data = Serial.read(); //Read the serial data and store it
Serial.println(data);
}
I was expecting NMEA sentences but to my surprise I was seeing just numbers coming out from by Helix 7 unit. Mostly 3-digit numbers but sometimes also 2-digit or single digit. I think I’ve hit a wall. I have no idea what these numbers are or how to treat this data. Would someone have any idea?