Another Yaesu VX-8DR external GPS with an Arduino/ATmega328 translator.

I've collected links for a few of these projects to add a better external GPS to the Yaesu VX-8DR, instead of the somewhat proprietary Yaesu option.

Here's another one from VK3YY that got posted recently:

• https://vk3yy.wordpress.com/2015/07/24/vx-8dr-and-gps/ 

Here's code from DFannin on github:

• Arduino code for buidling Yaesu VX8r Handheld Transmitter-compatible GPS

Update 2016-01-15, 4Z7DTF notified me about his project, which includes more additional analysis of how poor the VX-8's parsing and error handling is.

•  4Z7DTF's VX-8 Arduino GPS interface on github 

Background Info:

Good detailed blog post Reverse Engineering the Yaesu VX-8DR GPS Interface. From Feb. 2013. He didn't arrive at the solution, which I believe F4FXL and at least one other have. But I think he's got most of the relevant details for the padding differences listed as well as some other very useful info including details on the GPS chips used in VX-8 and VX-8G.

We now know how to connect to and send a properly formatted GPS NMEA message to the Yaesu VX-8DR. Here's the summary:

• 9600baud TTL 3.3V serial signalling, 8/N/1
  • NOT RS232 -5 to +5V signalling -- you need a level converter if that's all you have
• 3-wire physical interface to the following pins:
  

  Pin	GPS Side Purpose	Yaesu Side Purpose
  4	GPS RX	Yaesu TX
  5	GPS TX	Yaesu RX
  6	GPS GND	Yaesu GND

• According to 4Z7DTF (2016-01-15), there is no need for the communication to be bidirectional. Only the TX Data from the GPS to the VX-8 is required.

The messages need to be formatted exactly as follows: Message Type Source Sentence $GPGGA Sample $GPGGA,123223.000,4131.2334,N,00021.1216,E,1,04,02.7,00123.4,M,0051.7,M,000.0,0000*41 Syntax $GPGGA,hhmmss.sss,llll.llll,a,yyyyy.yyyy,a,x,xx,xx.x,xxxxx.x,M,xxxx.x,M,xxx.x,xxxx*hh $GPRMC Sample $GPRMC,123223.000,A,4131.2334,N,00021.1216,E,0000.00,291.33,301011,,*3E Syntax $GPRMC,hhmmss.sss,A,llll.llll,a,yyyyy.yyyy,a,xxxx.xx,xxx.xx,xxxxxx,,*hh $GPZDA Sample $GPZDA,123223.000,30,10,2011,,*55 Syntax $GPZDA,hhmmss.sss,xx,xx,xxxx,,*hh