Setting up a RN-XV WiFi module without a shield

I was looking for a cheap way of getting an Arduino online and the official ethernet and wifi shields were just too expensive. sell an RN-XV wifi module for around £30. There are a couple of issues I had to work through though:

Pin spacing
The little module has very tight pin spacing. It fits on the XBee Breakout Board but I didn’t want to spend any more so as you can see below, I did some terrible soldering to give myself direct access to 3.3V, GND, TX and RX pins. I may add some of the others later but that’s all you need to start with.

rn-xv wifi module

Getting It Set Up
There are lots of guides but they all either go through the shield, or were too complicated for my noob mind. It took me a long time but eventually after trudging through a bunch of details, I modified one of the Arduino example scripts to get me straight through to the module’s serial interface. The sketch is below:

Serial Passthrough to pin 89 based on the mega multi-serial example
#include <SoftwareSerial.h>
SoftwareSerial pin89Serial(8,9);
void setup() {
  // initialize both serial ports:
void loop() {
  // read from port 1, send to port 0:
  if (pin89Serial.available()) {
    int inByte =;
  // read from port 0, send to port 1:
  if (Serial.available()) {
    int inByte =;

Connect your RN-XV to your arduino as listed below:

Pin 1 (3.3V) to Arduino 3.3V (DO NOT connect to 5V)
Pin 2 (TX) to Arduino pin 8
Pin 2 (RX) to Arduino pin 9
Ping 10 (GND) to Arduino GND

…and upload the sketch. If you open the serial console, you’ll probably now see some output from the module. Either way, send ‘$$$’ with ‘no line ending’. You should get the response ‘CMD’. If so, you’re all good and you can now change to ‘Carriage Return’ in the drop-down and try ‘show stats’. You should get some stat output back.

If that’s all worked then try the following to get onto your WLAN:

set wlan phrase pass-phrase
set ssid network-name

Once it’s successfully rebooted, I’d suggest a firmware update. It’s easy and just requires you to go back into CMD mode with ‘$$$’ (remember to turn off the carriage return), then run:

ftp update

The manual suggests a factory reset so:

factory RESET
set wlan phrase pass-phrase
set ssid network-name

You should be all set now 🙂
There’s lots more info on the module’s page here

Dotsies – A New Way To Read

This is just a fantastic way to waste half an hour.

Go to and have a read. If you’re into typography or crypto (it’s not crypto, but it’s obscure enough that no-one’ll be able to read it) then I’d expect you to like this.

On their main page they use a really interesting method to help you learn the font by gradually removing the normal letters until you’re reading it unaided at the bottom of the page.

There’s a bookmarklet that lets you convert any page you’re reading to dotsies, but personally, I find it hard to read simply because the font is too small. A couple of hits of Ctrl-+ though and it’s fine.

Nerd fun 🙂