Ethernet Shield and APM Compatibility

Projects General Guidance
1

Hello All,

I am currently building a remote controlled submarine. The system will be comprised of a command/control station on shore, a relay buoy tethered via ethernet to the sub, and the sub itself. On board, I have a camera for a live HD video feed, as well as various measurement sensors. I thought an Ardupilot might be a good option for controlling the sub, as it includes certain features I would want to have aboard (e.g. gyros and accelerator). I have been able to obtain an APM for free, but I need to be able to use an ethernet shield so that I can get all the components linked to a switch and ran over the one tether line, and then sent over the radio wirelessly to the C/C station. Is there an ethernet shield that is recommended for the APM and would installation and configuration be similar to the Arduino Mega hack that I've seen posted? Thank you for any help you might be able to provide.

2

I use a 10DOF, GPS, 16 channel servo controller, and Mega2560/Ethernet shield through a Routerboard router remotely.

I don't know what you mean by the "Arduino Mega hack". It requires no hack.

3

The Ethernet Shield uses SPI (pins 10 through 13) so you would have to re-assign pins in ArduPilotMega to not use those pins.

4

@johnwasser: I see what you mean now. However, the ethernet shield has nothing connected to D11 to D13. The old "Mega hack" no longer works. You must jumper the ICSP pins on the ethernet shield to D50 to D52.

5

@SurferTim and @johnwasser : thank you so much for the help! So to verify, I re-assign pins D11-D13 to D50-D52 on the APM and then jumper them to the appropriate places on the shield? As you can tell, I am completely new to this. Thanks again guys!

6

Forget D11 to D13. There is nothing you need on those pins on the APM or the ethernet shield.

You must jumper the MISO, MOSI and SCK lines from the ICSP socket on the ethernet shield to D50, D51 and D52 respectively, and connect D10 on the ethernet shield to D10 on the APM.

I don't use an APM. I use an Arduino Mega 2560.

7

Oops. I thought the ArduPilotMega ran on an Arduino Mega. To use it with an Ethernet Shield you will need to figure out how to reach the SPI bus. There is an ICSP header for uploading firmware so that should help. five of the six pins would connect from there to the ICSP socket on the bottom of the Ethernet Shield. The 6th needed connection is from Pin 10 of the shield to Pin 10 of the APM. You'll need to find pin definitions of the APM to find out where Pin 10 is used. If Pin 10 is used for something vital you can change the Ethernet library to use a different pin.

Good luck!

8

The SPI pins are located on this pic lower right of the circuit board labelled "AT2560 SPI". Pin 1 should be the square pad.

Here is the schematic that shows the SPI pinout.

9

Again guys, very big help. I don't have that the red APM that you linked to, but I have the one in this link (below). From what I'm gathering though, they are the same thing just in different packages (correct?). You guys make it seem so easy! I guess it just takes better minds than mine haha.

http://plane.ardupilot.com/wiki/common-apm25-and-26-overview/

10

Take a look at this pic with no pins soldered on it.

Lower left, next to the USB connector are what appear to be the SPI pins. They are labelled "AT2560 SPI". The square pad should be pin 1. With the pins soldered to the board, they would be the last 6 pins in that row.

edit: It only seems easy. I've been hacking electronics for almost 30 years.
The SPI pins are even labelled on the side of the case.