Connecting a Wifly shield to an Arduino

I’m trying to make a more mobile version of my ‘remote control’

which connects to the web in order to send commands. My first version was with a Nanode with built-in ethernet, but I also have a Arduino Duemilanove ATmega168, so I thought I’d try that with my new Wifly shield and a battery pack.

The Wifly shield is this version and I have some stackable headers to go with it. I connected the shield on top of the Arduino like this:

You can see that the USB socket means that the shield is a bit high up.

I downloaded this version of the Wifly library that’s been recently changed to work with Arduino 1.0 Library. All connected up, and running this code from the examples:

#include "WiFly.h"

char passphrase[] = "pass";
char ssid[] = "ssid";

byte server[] = { 66, 249, 89, 104 }; // Google

Client client("", 80);

void setup() {



Serial.println("finished beginning");

if (!WiFly.join(ssid, passphrase)) {
Serial.println("Association failed.");
while (1) {
// Hang on failure.


if (client.connect()) {
client.println("GET /search?q=arduino HTTP/1.0");
} else {
Serial.println("connection failed");


void loop() {
if (client.available()) {
char c =;

if (!client.connected()) {

it was hanging on Wifly.begin().

After a bit of hunting round I found this detailed description of what might be up – essentially a timeout, and then twice only, while I was fiddling with the headers, SpiUartTerminal.pde worked.

The rest of the time it just hangs on this:

Attempting to connect to SPI UART...

So really I’m looking for a bit of advice – I don’t really want to solder it on, but are there better ways of connecting the shield to the Arduino? Are headers typically less reliable than soldering? Is there a better way to connect the shield somehow maybe using a breadboard? (e.g. like this). Or am I just doing something daft …?

UPDATE: Thanks to John (see comment below) I sorted out the problem, which was a newby issue: stackable headers need to be soldered! Anyway I persuaded Damian to solder for me (I’ve never done it before) and we now have a working wireless, battery-powered remote control:

(All it does is send the category to a http web service and that randomly chooses an item from all iPlayer available items in that category, and sends it to a web page connected with XMPP).

Thanks everyone who helped. I’m very pleased with it 😀

4 thoughts on “Connecting a Wifly shield to an Arduino

  1. Are the header pins soldered to the shield? In an earlier photo, on Flickr, they weren’t. The header pins must be soldered to the shield, and then plugged into the Arduino. They won’t make contact otherwise, which will lead to the symptoms you’re seeing.

    As for the USB connector, as long as the tracks that it touches are not connected to anything (i.e. blank prototyping area), then you’ll be OK. If you need to preent shorts, a small piece of plastic or even cardboard will insulate it.

  2. Thanks John, no, they were not soldered and that was the problem. Many thanks again!

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