Click through the break for information on the setup and source code to get the Arduino Fio onto the web.

The project uses an Arduino Fio as the microcontroller, a Microchip RN171XV wifi module to connect to the internet (hereafter described using the old part name, RN-XV), and a Mini12864 graphical LCD to show debug information. Here’s a part list for this project (assuming you already have a USB -> Micro USB cable):

• Arduino Fio (available on Amazon & Sparkfun)
• Mini12864 graphical LCD (available on Amazon & DX)
• Microchip RN171XV/Roving Networks RN-XV (available on Amazon & Sparkfun)
• XBee USB adapter – for programming RN-XV (available on Amazon, DX, & SparkFun)
• FTDI 3.3V USB cable – for programming Fio (available on Amazon, DX, & SparkFun)

Want to make it completely wireless? I also used a Lithium Ion Polymer battery (available at Sparkfun).

When you first get the RN-XV, it needs to be updated to the latest firmware. First, it needs to be plugged into the XBee USB adapter and connected to your computer. These days, I’m working on a Mac, so I use CoolTerm to communicate with the RN-XV. Here are the settings (basically 9600 baud serial communication):

Then the RN-XV needs to be connected to your wireless access point and updated. Type in $$$ to enter the command mode and you should see the RN-XV respond CMD. You can then enter the commands one by one (carriage returns after each line) to connect the RN-XV to your WiFi access point. Here is my basic setup (see the RN-XV datasheet for additional information):

[code lang=”text”]
factory RESET
reboot
set wlan auth 4
set wlan ssid XXXX
set wlan phrase XXXX
set wlan join 1
save
reboot
[/code]

The RN-XV should associate (connect) with your wifi network and then you can test the connectivity by pinging the Microchip FTP server:

[code lang=”text”]
ping 198.175.253.161 10
[/code]

Then, update the RN-XV to the latest firmware (4.00.1 as of this article’s publish date):

[code lang=”text”]
set ftp address 198.175.253.161
set ftp user roving
set ftp pass Pass123
save
ftp update
[/code]

Once the update downloads, you can reset the factory defaults and reboot:

[code lang=”text”]
factory RESET
reboot
[/code]

After the RN-XV resets, you should again enter the basic setup information to get the RN-XV connected to your WiFi access point (see above). If all works out, then you can disconnect the serial port and pull the RN-XV out of the XBee adapter for the time being (don’t put it into the Arduino Fio, because the Fio needs to be programmed and the TX/RX lines are shared on the board).

I found a wonderful Arduino library for the RN-XV called WiFlyHQ by harlequin-tech. The author includes a number of great examples, including a HTTP client, HTTP server, TCP client, UDP client, and web socket client. Using the basic setup code in the HTTP client example, I added code from my previous Arduino FIO Graphical LCD Console to make a simple “clock” that updates approximately every 3 seconds using the time-c.nist.gov time server. I used the console code because it allows for very simple debug printing (since the Fio’s serial TX/RX pins are shared with the XBee socket). Here an admittedly boring short video illustrating the “clock” being startup and allowed to run (the value on the far left is an indicator of the wireless signal strength, RSSI):

And finally, here’s the Arduino sketch:

More information on the project, a video of it in operation, and its code after the break.

A little while ago, I picked up an Arduino Fio (available on Amazon.com) and the mini12864 graphical LCD (available on dx.com & Amazon.com) for some microcontroller tinkering. It turned out that a great graphical LCD library was available — u8glib — that supports the mini12864’s controller (the UC1701).

Using u8glib, the Arduino and the GLCD communicate flawlessly. Thankfully, the mini12864 is 3.3V compatible, so there are no issues setting it up with the Arduino Fio and the simple SPI connection makes setup surprisingly easy. As mentioned, I was able to use u8glib to port my oscilloscope code from CCS C to the Arduino:

• Arduino FIO LCD Oscilloscope
• Arduino FIO 2 Channel LCD Oscilloscope

In addition to all of the functions u8glib provides, the library also comes with a nice little serial console/terminal demonstration program. The current u8glib console code can be found here.

I added four functions that would allow me to quickly and easily debug my applications u8g_print, u8g_println, u8g_print_P, and u8g_println_P. u8g_print allows one to print a character array, u8g_println does the same, but then adds a new line to the end of the string, u8g_print_P allows you to print a character array saved in program memory, and u8g_println_P does the same but adds a new line. Here are the new functions:

This allowed me to create this simple demo of the GLCD debug console code:

And last but not least, here is the Arduino Sketch used to produce the above output:

Here’s a short demonstration video of the new two channel project:

Click through the break to check out the code.

The project used an Arduino Fio (available on Amazon.com) and the mini12864 128×64 pixel graphical LCD (available on dx.com & Amazon.com).

The basic modification was to include a second set of variables that is used to store the second channel’s readings. A more elegant solution would have been to make each variable an N-channel array (so that one could easily scale to more channels), but the low-resolution monochrome display really limits the possibilities, unfortunately. In addition, the sampling rate for the single channel oscilloscope was already quite low (with a maximum sampling rate of approximately 28kHz), but two channels could allow for some interesting possibilities as long as one can deal with the slower acquisition speed.

The display refresh is triggered by a rising signal (useThreshold == 1) on the channel A input (analog pin 7, as defined by theAnalogPinA = 7), but you could easily modify the code to make this switchable so that either channel acts as the trigger. The code is very similar to my previous code, including the serial port parameter controls, so I recommend taking a look at that post first, if you have any questions: Arduino FIO LCD Oscilloscope

As with the previous single channel project, you need to make sure that you have the u8glib library installed to compile the code.

Here’s the Arduino sketch for the oscilloscope:

Here’s a short teaser video just to show that, yes, it works (going through a couple different sine wave frequencies, some random noise, etc. just to illustrate it working):

Click through the break to get more information on the setup.

I used an Arduino Fio board that I picked up from SparkFun.com (available at Amazon.com) and a small SPI graphical LCD board that I picked up for a few bucks at dx.com (SKU 153821, also apparently available at Amazon.com). Since I don’t have a soldering iron here, I had to improvise with some female to female cables, also purchased from dx.com (SKU 151650).

Dx.com describes the LCD as a 5V module, but the GLCD board designer’s page (mini12864) states otherwise (translated from Chinese via Google Translate):

Dimensions (L × W × H): 47mm × 38mm × 6mm (excluding pins)
LCD sight (L × W): 33.7mm × 33.5mm
LCD Active Display Area (L × W): 30.7mm × 23mm
Backlight: White LED backlight bracket
Operating voltage: 3.3V ~ 5.5V (built-in booster circuit, without pressure)
Control IC: UC1701
Display format: 128 × 64 rows
Display: Blue on White

(mini12864 datasheet)

So, I ordered one of the graphical LCDs, waited a few weeks for delivery (because dx.com is a notoriously slow shipper), received it, hooked it up, and tried out the following simple “Hello World” script to confirm that that the GLCD/FIO combo functioned:

And it worked!

Thankfully, the code I previously posted was written in C, so porting to the Arduino took only a few minutes. I took advantage of a great open source graphical LCD library (u8glib) to handle the brunt of the work and added a serial port menu for manipulating the various display parameters. One important difference between this project and the previous one: Since the Arduino Fio is a 3.3V device, it can only handle 0-3.3V inputs, limiting its utility as an “oscilloscope” without proper input protection/voltage scaling. However, the code is extremely portable, meaning that you should be able to program any other Arduino and have it up-and-running in no time.

Here’s another 2 videos of the oscilloscope in action:

And finally, here’s the Arduino sketch for the oscilloscope:

Here’s the Arduino sketch for the square wave generator shown in the second video:

Full Circuit

The source and firmware for the circuit can be found at the bottom of the page. Each section of the circuit is labeled in the schematic. All of the sections and their components are described and discussed below. The part numbers for the components are linked to websites for data and more information when available.

Power Supply

The power supply uses a 9 volt battery and a TC1262-5.0V high-accuracy low-dropout linear voltage regulator to provide a stable 5 volt supply for the microcontroller and the graphical LCD. A 1uF (microFarad) polarized decoupling capacitor is necessary on the output of the voltage regulator to prevent power spikes or ripples. A wall wart power supply as low as 5.3V can be substituted for the 9 Volt battery.

AZ Displays AGM1264F

The AGM1264F is 128 x 64 pixel graphical LCD with built in controllers that allow is to be easily controlled using a PIC microcontroller. It is a 128 x 64 pixel graphical LCD and has an LED backlight, onboard negative voltage generator (LMC7660) for LCD driving, onboard Samsung KS0108 controller, and an 8-Bit MPU interface.

Analog Input

The 1st analog input (Pin A0) is configured to be an analog input. Please note that “The source impedance affects the offset voltage at the analog input (due to pin leakage current). The maximum recommended impedance for analog sources is 2.5 kΩ.” (PIC18F2550, p.260)

Microcontroller

The microcontroller used is a Microchip PIC18F2550. I modified the PIC18F2550 Tiny PIC Bootloader assembly file so I could use a 20MHz crystal/resonator at 115,200 baud (the modified bootloader can be found at the bottom of the page). The PIC18F2550 runs at 48MHz using the internal PLL. R1 is a pull-up resistor necessary for operation. C1 is a stabilizing capacitor that is used for the onboard USB voltage regulator, which is not used in this project. The component marked ‘RES’ is a 20MHz resonator.

RS232 Level Converter

The microcontroller USART pins need to be connected to a RS-232 Level Converter to connect to a PC for firmware updates using the Tiny PIC Bootloader. Otherwise, after initial programming they can be left disconnected.

Source and Firmware
The PIC must initially programmed with the ‘SAC_tinybld18F2550usb _20MHz_115200_48MHz’ hex file to program the bootloader on the PIC. Then, using Tiny PIC Bootloader, the hex file can be placed on the chip using the Tiny PIC Bootloader frontend with ’12h 34h 56h 78h 90h’ in the ‘List of codes to send first:’ in the ‘Options’ menu. Please feel free to contact me if you have any problems.

• SAC_tinybld18F2550usb_20MHz_115200_48MHz.hex
• 18F2550 GLCD Oscilloscope DR1r1.c (hex)
• GLCD – modified.c

Videos
Here are three videos of the PIC18F2550 GLCD Oscilloscope in action. The first video demonstrates sine, triangle, and square waves of different frequencies. The second video demonstrates different waves with shifting amplitudes and offsets. The third video compares the display of the PIC18F2550 GLCD Oscilloscope to the display of a Hewlett Packard 54603B oscilloscope.

Update (November 15, 2006)
Here is the firmware without the bootloader code:

• 18F2550 GLCD Oscilloscope DR1r1 – no bootloader.c (hex)

Update (February 1, 2007)
Here is untested firmware for the PIC18F4550 without the bootloader code:

• 18F4550 GLCD Oscilloscope DR1r1 – no bootloader.c (hex)

Update (April 11, 2007)
Here is untested firmware for the PIC18F252 and PIC18F452 without the bootloader code. Please note that you will need to use a 10MHz crystal/resonator instead of a 20MHz one.

• 18F252 GLCD Oscilloscope DR1r1 – no bootloader.c (hex)
• 18F452 GLCD Oscilloscope DR1r1 – no bootloader.c (hex)