Slic3r Support Material Frustration

It’s been a few years since I’ve played with Slic3r, so I was eager to play with the current stable version, v1.0.1. One problem I had when playing with earlier versions of Slic3r was that the support material generation was not yet usable. A part I was designing had a big circular overhang in the middle, so it was the perfect opportunity to try out support meterial in v1.0.1 stable. Unfortunately, while the support material worked great for printing, it was almost impossible to remove! The gcode depicted below was generated using the rectlinear pattern:


The support material in the above picture is the large circular plug. Notice how it doesn’t leave a gap between the plug and the hole, so it’s completely stuck to the part! It took me almost an hour to carefully dig the support material out with and x-acto knife. Unfortunately, there’s no parameter in v1.0.1 to let you tune the spacing between the support material and vertical walls. Next, after reading that the Slic3r team had rewritten the support material code, I downloaded the latest experimental version, 1.1.4, and tried it. Much better:


Note the sizeable gap between the support plug and the perimeter of the hole. This time, the supports only took a few minutes to remove. The moral of the story? Use a newer version of Slic3r instead of v1.0.1 stable if you want to generate easy to remove support material. An added bonus of v1.1.4 is a new support pattern, called pillars. It looks like this:


RepRap: Printrboard Surgery

After a hiatus of a couple of years, I’m finally starting to get back into 3D printing. One of my Printrboards got messed up when some wires on my hot end shorted. The hot end temperature was no longer reading correctly. Since my other Printrboards all work correctly, I knew that the problem was not a bad thermistor or wiring. Instead of throwing out the Printrboard, I decided to try to fix it. The first step was to have a look @ the Printrboard schematic. Here’s what the temperature sensing circuit looks like:



I got out my ohmmeter, and R9 was OK, but E-THERM to GND was reading as a dead short, so I assumed that C10 was bad. This was a good opportunity to play with my AOYUE INT 2702 hot air rework station, which I’d never used. I removed C10, and much to my chagrin, the reading from the hot end ADC pin was stuck at 1024. Furthermore, shorting E-THERM to ground was causing my Printrboard to reboot! This led me to conclude that something was fried inside the AT90USB1286 on the ADC pin connected to E-THERM (PF1_ADC1). Conveniently, 2 other ADC pins, ADC2 and ADC3, are broken out into an expansion header on the Printrboard. I first soldered C10 back into place. The trace connecting ADC1 to E-THERM was inaccessible, so I couldn’t cut it. Instead, I disconnected it by lifting the pin on the MCU off the PCB. Next, I connected a piece of 40AWG wire wrap wire between the A2 header pin and the E-THERM trace.


Success, the ADC2 pin is working perfectly! The only caveat is that I have to remember to run modified firmware when using this board, reassigning the hot end thermistor pin from ADC1 to ADC2. In Marlin firmware, it’s as simple as finding the Printrboard section of pins.h, and reassigning TEMP_0_PIN from 1 to 2.

Arduino 1.0.5-r2 for AT90USB1286 and Printrboard

It’s been a few years since I hacked together the copy of Arduino-0022 that’s been floating around the web, which lets you compile and automatically upload Arduino code to an AT90USB1286. This made it a lot easier to develop Arduino code for the AT90USB1286, and in particular to easily modify the Marlin firmware for the Printrboard.

Yesterday, I figured it was high time to add AT90USB1286 support to Arduino 1.0.5-r2. The basic procedure for the modification was to first install Teensyduino, which adds the AT90USB1286 compilation support to Arduino, but only uploads to a Teensy++ 2.0, running PJRC’s proprietary halfkay bootloader. I modified the Teensyduino configuration to also support uploads to targets running the LUFA CDC Bootloader, or via USBtinyISP or USBasp ICSP programmers.

Note that I copy that I modified only runs on Microsoft Windows.
You can download it from github:
It’s easiest to download it as a zip file:

Once you unzip the archive and launch arduino.exe, you will notice some new entries in the Tools->Board menu:


The only difference between the Printrboard and AT90USB1286 entries is that the extraneous USB Type, CPU Speed, and Keyboard Layout submenus are grayed out from the Tools menu.

To load Marlin firmware onto a Printrboard, you will most likely want to use [BootloaderCDC]Printrboard.

Note that unlike my Arduino-0022 hack, the pinMode()/digitalRead()/digitalWrite() functions in version currently only support the pins that are exposed on the Teensy++ 2.0. This is because I haven’t yet had the time to figure out how to add in the remaining AT90USB1286. However, this limitation doesn’t affect Marlin firmware on the Printrboard, because Marlin uses its own fastio functions, rather than using Arduino digital pin numbers and pinMode()/digitalRead()/digitalWrite(). See pinmap.txt for the currently supported Arduino digital pin numbers.

Thanks again to PJRC for Teensyduino. Teensys are a great alternative to Arduino boards.

Tweaking the Action on a Roland FD-8 Hi-hat Pedal

Ever since I bought my Roland TD-3SW v-drum kit, I’ve found the included FD-8 hi-hat pedal to be a major annoyance. The problem is that I would practically have to stand on the pedal in order to get the hi-hat closed sound. Adjusting it according to the instructions in the manual didn’t help. I basically lived with it this way until my son recently wanted to start using my drum kit, and couldn’t apply enough force to the FD-8. It was time to fix the problem.

I googled around and found a few fixes, notably this discussion on FD-8 Hi-hat Controller Pedal – Notes on Improving Volume and Feel. However, I felt that the fix described in the thread seemed too hacky for my tastes. Finally, I found this video on YouTube by a brilliant German guy: How to fix a Roland FD-8 hihat pedal. I decided to try his method, and it worked great! My pedal now has action a lot more like a real hi-hat pedal; you don’t have to mash it down hard to get the “closed” sound. I’ve modified the procedure a little, and have documented it below:

Step 1: Remove screws

In the YouTube video, Marcel practically tears down the entire FD-8. Actually, you don’t really have to disassemble everything. All you need to do is get access to the problem parts. Remove only the screws pictured in the photo below from the bottom of the pedal:


This will allow you to separate the front plastic cover from the metal bottom. The bottom metal plate has a resistor attached to a small PCB via a ribbon cable, which is attached to the 1/4″ TRS jack. This is what the resistor looks like:


There is a rubber foot (show in a photo below), which presses along the resistor in order to tell your drum’s brain box the position of the pedal. The problem is that the rubber foot doesn’t press hard enough against the section that indicates hi-hat closed (low resistance), near where the ribbon cable connects.

When you open the case, the ribbon cable will be attached to the grey clip pictured below:


To release the ribbon cable, simply pull upwards on the grey part of the clip until it stops. Then the ribbon will easily slide out of the slot. The rubber foot is attached to the underside of the plastic cover:


The problem is that the rubber foot is extremely stiff, and doesn’t bend as easily as it should. To remove it, gently rock it back and forth while pulling upwards. In the video, Marcel sprays silicone lube on it to loosen it up, but mine wasn’t that tight.

The method shown in the video is to soften up the rubber foot by thoroughly coating it with petroleum jelly and letting it sit in a warm place overnight. Since petroleum jelly eats rubber, I decided to apply it only on the part that affects the flex action, and not on the contact surface:


In particular, notice how I avoided applying petroleum jelly to the narrow protruding ridge. This keeps it from softening the ridge, which we want to remain hard, to maximize the pressure and lessen wear.

I left the rubber foot on top of my cable TV set top box (a consistent heat source) overnight. The next morning, the rubber was considerably softer, and I could tell that it was taking a lot less force to flex it. Again, here’s where I deviate from Marcel’s video. He initially applies the petroleum jelly a lot thicker than I did, and says to wipe it off after the rubber softens, leaving a layer that’s approximately as thick as what I applied in my photos above. Instead, I wiped the petroleum jelly residue completely off with a paper towel. I figured that some of it would still be soaked into the rubber, and that would be enough. Better than having it eat through the rubber until it turns to mush.

Reassembly of the pedal is just the reverse of the dis-assembly steps. When re-inserting the ribbon cable into the gray connector, make sure the gray connector is pulled up while inserting the ribbon cable, and then press it down to lock the cable in place. Also, be sure that the metal tongue pictured below has a layer of silicone grease on it:


Mine still had enough lube on it from the factory, so I didn’t apply any extra. The rubber foot slides against this metal tongue when you press the pedal, so if it isn’t lubed properly, the pedal may need extra pressure. DO NOT use petroleum jelly here, because it will slowly melt the foot, and probably turn it into mush over time. Silicone lube, on the other hand, does not react with rubber. You can get small quantities of silicone grease in most auto parts stores.. it’s used on the rubber bits of brake parts. Also, you can buy it pool supply stores, or at a hardware store. This cheap stuff at Home Depot should work OK: Silicone Faucet Grease.

My pedals has great action now! I’m not sure if it will harden up in a few months, but the hack is easy and I’d rather play the hack on the conservative side. An alternative hack would be to drill holes along the side of the rubber foot, thus lessening its tension. I was originally going to do this, and it turns out someone on successfully did it (see the the 2nd to last post on this page), but in the end, I decided to first try the petroleum jelly method, since it was less invasive. Thanks again to Marcel (vdrumtips).

How to Update the Firmware on a USBasp V2.0

If you buy a cheap USBasp V2.0 ICSP programmer on eBay, chances are, avrdude will give you the following warning message:

avrdude: warning: cannot set sck period. please check for usbasp firmware update.

While it’s just a warning message, it’s still a constant irritant. To get rid of this warning, you must update the firmware to the latest version: usbasp.2011-05-28.tar.gz

If you have another ICSP programmer already, such as a USBtinyISP, programming in the new firmware is quite simple. Here are the steps:

0. Verify that you have a USBasp V2.0, and that it has a 12MHz crystal and an ATMEGA8 or ATMEGA8A MCU onboard. DO NOT CONNECT IT TO THE USB PORT OF YOUR COMPUTER.

1. Short the JP2 (self-programming) jumper.

2. Connect the USBasp V2.0 to the USBtinyISP using a 10-pin ribbon cable


3. Reprogram the USBasp’s fuses: avrdude -c usbtiny -p atmega8 -u -U hfuse:w:0xc9:m -U lfuse:w:0xef:m

4. Flash in the new firmware: avrdude -c usbtiny -p atmega8 -U flash:w:usbasp.atmega8.2011-05-28.hex

Note that the usbasp.2011-05-28.tar.gz archive doesn’t contain a compiled .hex file, so you have to re-compile it using WinAVR. Instead, you can just use my hex file, which I compiled directly from the sources:

If you don’t have another ICSP programmer, you can use an Arduino, following these instructions: Updating firmware on USBASP bought from eBay. However, you may also have to also set the fuses according to Step 3 above. My PC wouldn’t recognize the reprogrammed USBasp until I set the fuses.

Interfacing a TFT_320QVT LCD/Touchscreen/SD to a Teensy 3.0

I’m working on a project which needs a touchscreen LCD. After searching eBay for a while, I noticed that many vendors were selling basically the same 3.2″ 320×240 TFT with resistive touchscreen and SD card reader. Though there were slight variations in the silkscreens, they all had the same model number – TFT_320QVT. I bought mine from digitalzone88 for $12.29. TK0466-1-digitalzone88 TK0466-4-digitalzone88 The board uses a SSD1289 LCD driver IC, and runs on 3.3V. The 3.3V voltage is incompatible with the typical Arduino, which runs at 5V (some vendors have created shields to interface it to an Arduino Mega). However, I purchased the TFT_320QVT with the intention of interfacing it to a Teensy 3.0, which runs at 3.3V. I noticed that there were not enough through-hole I/O pins on Teensy 3.0 to simultaneously interface to the LCD, touchscreen, and SD card. This necessitated the usage of the Teensy 3.0′s additional I/O pins, accessible only via solder pads on its underside: teensy3b To facilitate access to the 14 solder pads, I attached some header pins to piece of stripboard, and soldered 40AWG wire-wrap wire to between the pads and headers: extenderThe Teensy 3.0 runs on PJRC’s specially modified version of Arduino – Teensyduino. The task was to find compatible Arduino libraries. First order of business was the LCD. I searched the web, and found that dawnmist had spent a considerable effort in modifying Henning Karlson’s UTFT to work with the Teensy 3.0. Unbeknownst to me at the time, dawnmist’s modified UTFT is actually bundled with Teensyduino!

Next, was to get the touch screen working. It turns out that the current version of Henning Karlson’s UTouch is compatible with the Teensy 3.0.

For the SD slot, I tried the version of the Arduino SD library that’s bundled with Teensyduino. Unfortunately, though the SD library works with the TFT_320QVT’s SD reader, it stops working if you instantiate a UTFT object in the sketch. I tried sdfatlib, and found that not only does it work w/ the Teensy 3.0, but it coexists fine with UTFT. The only catch I found is that it works only with SPI_HALF_SPEED. When I set it to SPI_FULL_SPEED, it stops working.

Here is the Teensy 3.0 running UTFT‘s demo sketch on the TFT_320QVT: utft

Below is the step-by-step procedure to getting the TFT_320QVT up and running with Teensy 3.0:

Step 1: Install the libraries

1. UTFT: Run the Teensyduino installer, and when the Libraries to Install dialog is displayed, check the box next to UTFT in the Choose Additional Libraries to Install combobox. (Note: Henning Karlson’s latest UTFT also works with Teensy 3.0, but my discussion below will show how to interface to the UTFT that’s bundled with Teensyduino 1.18).

2. UTouch: Download UTouch.rar. Use WinRar or 7-zip to extract the enclosed UTouch folder. From the Arduino IDE pull-down menu, use Sketch->Import Library->Add Library… to install the extracted UTouch folder. Alternatively, you can just copy Utouch/ to your arduinosketchbook/libraries directory.

3. sdfatlib: Download the latest version of sdfatlib. From the Arduino IDE pull-down menu, use Sketch->Import Library->Add Library… to install the downloaded file. You can alternatively just extract the SdFat/ folder into your arduinosketchbook/libraries directory.

Step 2: Wire it up

1. LCD: dawnmist‘s modified UTFT library that’s bundled with Teensyduino has a configuration file: arduinofolder\libraries\UTFT\hardware\arm\HW_Teensy3.h. Inside HW_Teensy3.h, there are 3 options for the LCD pin assignments: USE_B_D_PORTS, USE_C_D_PORTS, and USE_USER_PORTS. By default, the file has


enabled. USE_B_D_PORTS gives the best performance when your sketch needs to use SPI (which is needed for the SD card slot). USE_C_D_PORTS gives the fastest performance, but is incompatible with SPI. USE_USER_PORTS allows you to configure arbitrary pins (by changing the DB_0-DB_16 #defines), but results in the slowest performance. I elected to use the default USE_B_D_PORTS setting.

2. SD card reader: The SD card reader works via SPI, so it needs to use SD_DIN->DIN (MOSI – 11), SD_DO->DOUT (MISO – 12), SD_CLK->SCK (13), and one of the chip select pins, CS0-CS4 (10,9,20,21, or 15). I chose to use SD_CS->CS4 (15).

3. Touchscreen: The touchscreen uses 5 pins, T_DIN/T_DO,T_CS/T_CLK/T_IRQ, which can be assigned to any arbitrary free GPIO pins.

Below is a chart of my pin assignments:

Teensy_pin = TFT_320QVT_pin
0 = LCD_DB4
1 = LCD_DB5
2 = LCD_DB8
3 = LCD_LED_A (backlight)
5 = LCD_DB15
6 = LCD_DB12
7 = LCD_DB10
8 = LCD_DB11
11 = SD_DIN (MOSI)
12 = SD_DO (MISO)
13 = SD_CLK (SCK)
14 = LCD_DB9
15 = SD_CS
16 = LCD_DB0
17 = LCD_DB1
18 = LCD_DB3
19 = LCD_DB2
20 = LCD_DB13
21 = LCD_DB14
22 = LCD_WR
23 = LCD_RS
24 = T_CLK
25 = LCD_DB7
26 = T_CS
27 = T_DIN
28 = T_DO
29 = T_IRQ
32 = LCD_DB6

LCD_RD needs to be pulled up to 3.3v

I have created a sketch, UTFT_UTouch_SdFat_teensy3, that simultaneously demonstrates the LCD, touchscreen, and SD card by modifying the UTouch demo sketch. Below are the lines which are critical to configuring it to work with the above pin connections:

#include <UTFT.h>
#include <UTouch.h>
#include <SdFat.h>

// bitmap file to load as background.
// must be 320x240 and in format output by ImageConverter565
char bkgRaw[] = "ade.raw";

uint8_t sdCS = 15; // SD_CS - chip select
SdFat sd;
SdFile inFile;

uint8_t lcdRS = 23;
uint8_t lcdWR = 22;
uint8_t lcdCS = 4;
uint8_t lcdReset = 9;   
uint8_t lcdBacklight = 3; // must be a PWM pin for variable brightness
uint8_t lcdBacklightBrightness = 255; // 0-255
UTFT myGLCD(SSD1289, lcdRS, lcdWR, lcdCS, lcdReset);

// Initialize touchscreen
uint8_t t_Clk = 24;
uint8_t t_CS = 26;
uint8_t t_DIn = 27;
uint8_t t_DOut = 28;
uint8_t t_IRQ = 29;
UTouch myTouch(t_Clk, t_CS, t_DIn, t_DOut, t_IRQ);

The file displays a bitmap, ade.raw, as the background. Before running the sketch, copy ade.raw to a FAT-formatted SD card, and insert it into the TFT_320QVT’s SD card slot.

You can also substitute your own bitmap file. To create a .raw file, first create a 240×320 pixel jpg, png, or GIF file. Run it through either imageconverter565.exe (bundled with UTFT) or the online ImageConverter 565 make sure to select Convert to .raw file and Target Platform Arduino (AVR).

Here’s what UTFT_UTouch_SdFat_teensy3 looks like when it’s running:

Many thanks to dawnmist, and the others who figured out how to get UTFT working with the Teensy 3.0.


I obtained much of the information I needed from these pages:
dawnmist – screen working … finally
Teensy 3.0 – driving an SSD1289 with utft

Arduino IDE suddenly freezing up? Here’s how to fix it.

Every once in a while, my Arduino IDE suddenly takes forever to launch, sticking at the splash screen for a long time. Even after it launches, it’s still basically unusable, because the pull-down menus also freeze up, and take an eternity to respond. It happens to me every time I download a new Arduino IDE, which is so infrequent that repeatedly forget why it happens, and how to fix it. After ripping my hair out for a while, I start googling until I find the fix.

If you’re experiencing this problem running Arduino on Microsoft Windows, chances are, you have a virtual serial port from a Bluetooth SPP device installed in your system. The problem is that the Arduino IDE is trying to enumerate your system’s serial ports in order to locate the attached Arduino devices, and the code takes a long time to timeout. Luckily, user eried in the Arduino forums figured out what was happening, and posted a fix in the thread: Road to solve the delay in Arduino IDE. He has graciously come up with a workaround, and shared it with us.

The fix is easy. Simply download his rar file, extract his new rxtxSerial.dll, and replace the version that’s currently in the same directory where your arduino.exe resides. I’ve also attached a zip archive of the file below, for those people who don’t want to install WinRAR in order to get the new rxtxSerial.dll. Thanks, eried!


ITEAD Studio IBOX – Part 3: Installing Java and Processing

ITEAD Studio asked me how to install Processing 2.1.1 on Debian 7.0 running on the IBOX, because they want to use the IBOX as a Lampduino controller. This article describes the installation procedure. All of the commands must be typed into a shell Terminal.

1. Install openjdk and librxtx

# apt-get update
# apt-get install openjdk-7-jdk librxtx-java

2. Download and extract Processing for 32-bit Linux

# cd /opt
# wget
# tar xzf processing-2.1.1-linux32.tgz

3. Remove the x86 Java bundled with Processing and link to OpenJDK

# cd processing-2.1.1
# rm -rf java
# ln -s /usr/lib/jvm/java-7-openjdk-armhf java

4. Modify the serial support for ARM

Unfortunately, Processing 2.1.1 no longer uses RXTXcomm.jar, so we have to copy the serial support from Processing 2.0.3, and then modify it for ARM:

# cd /opt
# wget
# tar xzf processing-2.0.3-linux32.tgz
# rm -rf processing-2.1.1/modes/java/libraries/serial
# mv processing-2.0.3/modes/java/libraries/serial processing-2.1.1/modes/java/libraries
# rm -rf processing-2.0.3*
# cd processing-2.1.1/modes/java/libraries/serial/library
# rm RXTXcomm.jar
# cp /usr/share/java/RXTXcomm.jar .
# rm linux32/
# cp /usr/lib/jni/ linux32

Congratulalions, you have a working copy of Processing! Start Processing by launching /opt/processing-2.1.1/processing

** Optional Steps Below **

Processing complains that it doesn’t like OpenJDK when it’s launched. If you want to accelerate the performance, and improve compatibility, you can follow the additional steps below and install the hard float version of Oracle Java 7 SE Embedded. The OpenJDK 7 that’s installed via apt-get ignores the A20′s hardware floating point unit, and instead uses software emulation.

5. Download Java SE Embedded 7 update 51

Unfortunately, Oracle makes you accept a license agreement, which requires cookies, making download a lot messier than just running wget.
Use a web browser to navigate to the Java SE Embedded Downloads page. Click the Accept License Agreement radio button near the top of the page, and then click the link corresponding to ARMv6/7 Linux – Headful EABI, VFP, HardFP ABI, Little Endian. The next page requires you to log into an Oracle account. If you don’t have one, you can create one for free. Save the file the /opt directory. The included web browser wasn’t working in my copy of ITEAD Debian 7.0. If you need a web browser to download Java, you can use iceweasel:

# apt-get install iceweasel
# iceweasel

6. Install Oracle Java SE Embedded 7

# cd /opt
# tar xzf ejre-7u51-fcs-b13-linux-arm-vfp-hflt-client_headful-18_dec_2013.gz

The .gz file will extract into a directory at /opt/ejre1.7.0_51.
7. Modify Processing to use Oracle Java SE Embedded 7

# ln -s /opt/ejre1.7.0_51 /opt/processing-2.1.1/java

When you launch Processing 2.1.1, it should no longer complain that it doesn’t like the version of Java that you’re using. I found that the hardware floating support Oracle Java 7 gives a big speedup in any code that has floating point computations.

Previous Article: ITEAD Studio IBOX – Part 2: Booting up Debian Linux 7.0

ITEAD Studio IBOX Part 2: Booting up Debian Linux 7.0

My IBOX came shipped with Android TV A20 pre-loaded in the NAND flash. I plugged a Microsoft keyboard and mouse into the USB ports, and used my Panasonic plasma TV as a HDMI display.  The boot screen is a bit confusing, because it implies that the device has WLAN support:


You can ignore the big WLAN banner on the screen, because the IBOX only has a RJ-11 100BT Ethernet port. The main screen has typical media center functions. Applications takes you into an Android launcher screen, Settings takes you to a typical Android settings screen. Going to the Applications screen shows that it has some typical apps pre-installed:


Most notable is the Google Play store support. I tried logging into Google Play and installing a few apps. They worked fine. However, I’ve heard that YMMV … some apps don’t work properly. Adobe Flash is also pre-installed, which is a plus. I did not play with it much, beyond some cursory tests, because I am more interested in running Debian Linux on the IBOX. ITEAD has a Debian 7.0 image, which runs off an SD card. Instead of downloading the version from ITEAD’s OS page, I used an alpha version built on 2014-03-27 which ITEAD sent me. To install it, first extract the  iteados-A20-debian-xfce-2.0-alpha-2014-03-27.img file from the downloaded.bz2 archive. I used WinRAR on my Windows machine to extract it. The image file needs to be copied to a 4GB or bigger micro SD card. Note that the .img file cannot be copied to a FAT-formatted SD card, because it contains an entire Linux filesystem. Instead, it must be raw-copied using a utility. In Windows, Win32 Disk Imager is a free utility that fits the bill:


Simply select the image file and the SD card’s drive letter, and then click the Write button. After the image is successfully written, insert the microSD card into the IBOX, and power it up. If all goes well, you will first see two Linux Penguins in the upper left corner of the screen. After a while, the login screen should appear:


Log in with user: root, password: root. While Android TV A20 was incompatible with my Dell LCD monitor (all I got was a blank screen), Debian 7.0 is working great. Unfortunately, I’m having the same problem with both my Dell LCD and my Panasonic plasma: when the screen blanks out after inactivity, I am not able to wake it up again. Therefore, I have to reboot it after every time the screen blanks. Hopefully, ITEAD will be able to tell me how to fix this.

Previous Article: ITEAD Studio IBOX – Part 1: First Look
Next Article: ITEAD Studio IBOX – Part 3: Installing Java and Processing

ITEAD Studio IBOX – Part 1: First Look

ITEAD Studio recently contacted me to let me know that they’re going to display my Lampduino project at the Shenzhen Makerfaire. I thought that was a pretty cool idea, and am honored to hear that. They also asked if I wanted to test out their IBOX mini multifunction single board computer, which is currently in its final days of its campaign on Indiegogo, having already raised over 4.5x its funding goal. The IBOX is designed with hackers in mind, and is driven by an Allwinner A20 ARM Cortex-A7 processor. Here are the salient hardware specs:

  • CPU Dual-core ARM Cortex-A7
  • GPU Mali 400 MP
  • DDR3 RAM 1GByte
  • 4x USB
  • 1x HDMI
  • 1x optical S/PDIF
  • 1x 100BT Ethernet
  • 1x 7-24V DC power jack

ITEAD touts the IBOX as a very open hackers platform, capable of running a plethora of OS’s.  Currently, the following distros are available for booting from its onboard NAND flash:

  • Android TV A20 (from ITEAD)
  • Android 4.2 (from Cubietech)
  • Lubuntu (from Cubietech)

The following distros must be booted from the microSD:

  • Android SD bootable image (from LinkSprite)
  • Debian 7.0 (from ITEAD)
  • Cubian (from Liu)
  • Arch Linux (from

The IBOX comes in an anodized aluminum case that has a glossy plexiglas top:


Being a pre-production sample, I’ll excuse the fact that the top had a lot of superficial scratches on it, but I wonder if a matte surface would be better, since it scratches so easily. The left side of the unit contains a plethora of connectivity:


The small rectangle on the left labeled Uboot is a switch for entering the U-Boot bootloader. The right side contains a micro SD slot:


Behind the rectangular window is a 2-color status LED and an IR receiver for talking to remote controls. The back panel contains a 32-pin expansion interface connector:


The expansion connector is what really separates the IBOX from the typical ARM mini PC. It opens up the platform for hardware hackers, containing pins for UART, TWI, SPI, SATA, etc.  You can find the full pinouts on the Indiegogo page. The bottom of the IBOX is held on with 4 Philips screws:


A set of rubber feet would be a nice addition.  Removing the metal bottom cover reveals the bottom of the baseboard:


The baseboard is a very tight fit into the case.  In order to remove it, you must first pry the it away far enough to clear the various ports from their cutouts in left side of the case, and then pry upwards from the front.  The baseboard is a modular backplane which contains all of the I/O connectors, as well as the socketed core board:


The core board is essentially the “brain” of the IBOX, containing the A20 processor, RAM, etc. Since the core board is socketed, it can be swapped out as newer, more powerful ones become available (e.g. A31, etc).  Here is a close-up of the A20 core board:


Note that there are two pushbuttons, SW1 and SW2. I’m not sure of their purpose, but they are not accessible when the IBOX is assembled. The plexiglas top was attached to my IBOX with some rather messy clear silicone caulk:


Again, I’ll excuse the mess because it’s a pre-production sample. I hope that the production units will have cleaner assembly.

So far, the IBOX looks like an interesting platform for building an energy efficient media center, file server, http server, etc. I’m looking forward to powering it up and putting it through its paces. Perhaps I will use it to replace my Raspberry PI that’s currently running XBMC. In my next article, I will boot up the IBOX, and test it out.


Indiegogo campaign – the most information can currently be found on this page.
ITEAD blog – contains various informative posts on the IBOX
A20 core board schematic
IBOX baseboard schematic
IBOX baseboard design files
Case dimensions
distro downloads