Interfacing a Garmin Striker Vivid 4CV sounder

[aboon]

I was tempted by the low price of the Garmin Striker Vivid 4CV echo sounder when looking for a replacement for my venerable GPS60. I use the GPS60 in conjunction with an active transducer (Brookhouse) when sounding in my dinghy. The GPS60 received the sonar data (NMEA 0183 DPT sentences) and included it in the track log. I then massaged the track log to produce a GPX file of waypoints, with the adjusted depth (tide, pressure, transducer depth) displayed as the waypoint name.

However I, and many others, didn’t read the fine print and found that, although the Striker unit has ‘Data In’ and ‘Data Out’ wires, the only way to get data in and out of the Striker is to connect it to a higher-spec Garmin unit. Google found a couple of attempts to decode the data from the Striker but none reported success. I took up the challenge and have managed to get the track log that I need for my sounding. With the cost and effort involved, I would have been better off buying a more expensive model with an SD card slot – but I didn’t, so here are the details for anyone wanting to use the Striker Vivid 4CV.

With the exception of the Physical Protocol, the Garmin Device Interface Specification (IntfSpec.pdf) applies, although the version I used (dated Apil 14, 2020) did not include full details for the Striker Vivid 4CV.

Serial data: 115.2 kb/s, 8N1, no flow control and inverted TTL levels. Data Out on the blue wire, In on the brown wire.

The following is a response to a Product Request Command:

[Product Data:]
Striker Vivid 4cv Software Version 2.30 VERBMAP None VERSMAP None VERSPLSCRN Splash Scrn, 272x480 RGB5551, GARMIN 1.0 BACKLIGHT LED

[Extended Product data:]
VERGPROM None

[Protocol Array:]
P000 L001 A010 T001 A100 D110 A201 D202 D110 D210 A301 D312 D302
A400 D110 A600 D600 A601 D601 A700 D700 A800 D800 A900 A902
A903 A601 D601 A907 D907 D908 D909 D910

Fields of the Protocol Array refer to definitions in the IntfSpec document. I don’t know what ‘T001’ is. The Product Data includes prod_ID of 4100.
I used an Arduino Nano Every to translate the data packets to/from the Striker and a single transistor inverter on both Data In and Data Out lines. If anyone is interested in my Arduino code, I’m happy to send it on.

Andrew