Displaying Intel Galileo IP address on a 16×2 LCD

I’ve had problems with Galileo Watcher showing Galileo boards on Windows 8.1. It works fine on Windows 7 and as far as I am aware Windows Firewall is configured correctly. I was also a little inspired by this question on stackoverflow, I’ve copied the title of the question for this blog post. The nub of the question is this…

“What’s the best way do get and show the Galileo IP address on the display instead of “Hello!” message?”

I’ve used the 16×2 LCD with netduino projects and decided to have a go. The only answer to the  question suggested using the Windows APIs to get the IP address in string form and then use lcd.print to print the string to the LCD. I thought I would add a bit more value and also print the computer name to the LCD.

I decided to split the problem into three steps:

• Write a C++ console app to get the IP address (and other network adapter properties)
• Get the LCD sample app (http://ms-iot.github.io/content/16x2LCD.htm) working
• Merge the two projects and display the Galileo IP address on a 16×2 LCD

Step 1 – Writing a console app to get the IP address:
The GetAdaptersInfo page on MSDN gives a good example of a suitable console application. The application worked fine on my laptop. The Galileo runs a modified version of Windows with a subset of Win32 so I copied the console application to the Galileo and ran it successfully:

I now had code capable of retrieving the IP address and Computer Name.

Step 2 – Get the LCD sample app working:
I followed the instructions on setting up the 16 x 2 LCD from the sample applications on github. Unfortunately the project would not build. As a quick fix I modified the include files in the local package:

• Add #ifndef directive to Print.h:
• Remove the inheritance from the Print class in Stream.h

Step 3 – Merge the two projects
This was pretty straightforward, the only change I made between the console app and the Galileo project was changing from GetComputerName to GetComputerNameA to print the computer name to the LCD. The code snippet below runs in setup:

	lcd.begin(16, 2); // columns and rows, LCD unit (it calls clear at the end of begin)
	lcd.setCursor(0, 0);

	DWORD len = 16;
	char cName[16];

	GetComputerNameA(cName, &len);

	lcd.print(cName);
	
	PIP_ADAPTER_INFO	pAdapterInfo = NULL;
	PIP_ADAPTER_INFO	pAdapter = NULL;
	ULONG				ulOutBufLen = sizeof(IP_ADAPTER_INFO);
	DWORD				dwRetVal = 0;

	pAdapterInfo = (IP_ADAPTER_INFO *)MALLOC(sizeof(IP_ADAPTER_INFO));
	if (pAdapterInfo == NULL) {
		printf("Error allocating memory needed to call GetAdaptersinfo\n");
	}

	if (GetAdaptersInfo(pAdapterInfo, &ulOutBufLen) == ERROR_BUFFER_OVERFLOW) {
		FREE(pAdapterInfo);
		pAdapterInfo = (IP_ADAPTER_INFO *)MALLOC(ulOutBufLen);
		if (pAdapterInfo == NULL) {
			printf("Error allocating memory needed to call GetAdaptersinfo\n");
		}
	}

	if ((dwRetVal = GetAdaptersInfo(pAdapterInfo, &ulOutBufLen)) == NO_ERROR) {
		pAdapter = pAdapterInfo;
		lcd.setCursor(0, 1);
		lcd.print(pAdapter->IpAddressList.IpAddress.String);
	}

	if (pAdapterInfo)
		FREE(pAdapterInfo);

Computer name and IP address on a 16×2 LCD display…

I’ll tidy up the source code and update the blog post shortly…