NMM-1 an NMEA tester
A small portable NMEA0183 comunications tester and monitor.
The main function is suppose to display the serial comming from an NMEA0183 device but this is not yet implemented in the firmware,
the code is open fill free to try 😊.
It is using the ATMEGA328P microcontroller with the Arduino firmware configured has a
Pro mini arduino board.
Right now it displays a small menu with four options, the first three send out an NMEA0183 signal for GPS, Heading and Depth. The fourth option makes the device
a serial to USB adaptor, for both RS232 and RS422, which comes in handy when you are interfacing electronics equipment on the field.
It has a small I2C OLED monochrome 128x64 screen capable of very small and yet detailed graphics and uses four buttons for navigation, up, down, enter, back/cancel.
It was also added two LEDs for color messages or any other function but it was never used, again the
code is open fill free to try 😊.
Finally a small molex screw connector to easy plug any type of wires from equipments to test and/or interface.
Features
- Small OLED screen
- Battery powered, rechargeable via USB
- USB to serial adaptor mode
- Four mechanical buttons for menu navigation
- GPS, Heading and Depth signal injector
- Pro mini arduino programming
Schematic
This board was design in Kicad, here is the CAD project
Printed circuit board
All the parts are in the schematic if you need more information just contact us, there should be some parts still laying around.
Everything was hand soldered
In the first picture we can see the microcontroller under the screen, the second picture show the hand soldering this was a challenge for sure and the third picture shows the back of the PCB where the crystal and the reset button is located.
Here is the inside of the box fully connected.
Some pictures of the final assembly.
You can also find the entire git repo in here
Created on 12-04-2017