Marine GPS/Sensor logger and data uploader to Wordpress Blog

The idea is to have an Arduino log values from GPS NMEA data of a Lowrance HDS 7 Gen.1 and other sensors like a Water Level and 3-Axis compass. The Arduino will use a an Ethernet Shield to hopefully connect and send data to a PHP file on the web server at to blog automatically an entry so that it plots the GPS coordinates, a picture frame taken from a PTZ camera and the sensor data. Any ideas an help is appreciated. What I currently have is an Official UNO R3, Ethernet Shield Wiznet W5100, SainSmart UNO R3 3.3V-5V MEGA328P-AU ATMEGA16U2, soil hygrometer moisture sensor detection modul(water level meter), MAX485 module RS-485 TTL to RS485 MAX485CSA Converter Module, I2C MAG3110 3-Axis Digital Compass Magnetometer Module and 1602 16x2 LCD Character Display + IIC/I2C/TWI Serial interface Board Module

I am wanting to also control the PTZ camera from a joystick AND online on the website though I know it will be a challenge. It would be nice to use the LCD module to display alarms, along with a tone output when there is an alarm, I am willing to purchase what ever i need also.

Could shift registers be used to add extra Digital I/O pins? Should I use more than one arduino to do all of this? what are your thoughts?

Thank you!


Sounds like a brilliant project, and you've already got a stack of gear together so I presume you've done some reading on what you'll be doing.

I'd seen this Youtube video by Mike McRoberts (here) showing how to decode NMEA 2000 data from a GPS module by an Arduino. I couldn't find the specific Gen 1 of the Lowrance HDS-7 you mention but the current version does have ethernet though there's no documentation I could find on just how it talked to the outside world.

You can certainly use the Arduino to log data to the web so long as you have access to the API. Typically a simple HTTP GET or POST method would be used, where the data is presented as comma separated values in text which is all very achievable. Once you know what is required by the web service the rest you should be able to piece together with some google-fu.

I'm not sure about your soil hygrometer as a water level meter. Is this for monitoring your bilge? Those I've seen are prone to corrosion so probably not terribly effective nor robust in a marine environment (not that much is). Also, they measure the resistance change when the soil gets moist between the probes - whereas salt water would be far more conductive, so will be interesting to see the readings. Perhaps a plastic float switch or similar might be better if that's what you're planning.

You can certainly control a PTZ camera from an Arduino, but depending on the model you've got you may find it already has the ability to be controlled via the interweb to save that complexity for you. As for uploading an image, that's not really Arduino's forte, but again you may find an IP enabled camera already has that capability.

Could shift registers be used to add extra Digital I/O pins? Should I use more than one arduino to do all of this? what are your thoughts?

Presuming you do run out of IO pins there are many alternatives - shift registers are one, but it will really be determined on what kind of IO you need additional to what you have on hand. As you suggest one alternative might be to hand off some of the tasks to a 2nd Arduino, or perhaps something a bit beefier like a Raspberry Pi or similar for the image handling.

All the best,