Hacking hardware for chumby

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Building OpenEmbedded (Beta)
NeTV developer info

What questions do you have about hacking the hardware?

Please post questions here, and someone will attempt to create a sub-page to answer it! Or, check out the forum to see if your question has already been answered.

Where are the schematics found?

Hardware schematics and related materials can be found at http://www.chumby.com/developers/hardware/ which will require you to login and accept the Chumby HDK License (which you can read at http://www.chumby.com/developers/agreement ).

Are there plans to port Android to run on Chumby? This would be very exciting.

Add a video connector to the chumby One

Chumby Hacker Board

Chumby hacker board documentation

Hacker board boot information

What's in a chumby one?

Here's the schematics.
Here's the gerbers.

Some handy tips and tricks

chumby One tips and tricks

chumby One boot information

Running Tor

Running Tor on chumby One
nload cross-compiled for chumby One


Getting Phidget on chumby


Compat-wireless driver on chumby

Basic specs

  • 454 MHz Freescale i.MX233
  • Hynix 512Mbit DDR SDRAM (16-bit)
  • 2 Gbyte microSD card (brand/type and capacity may vary depending on market availability, as of 4Q09 a 2GB Kingston brand card can be found in the device, although Samsung OEM and Sandisk cards ranging from 1GB - 4GB have also been qualified for use; some anecdotal testing has seen 16GB cards working but there has been no rigorous testing for compatibility.)
  • One external USB 2.0 High speed port
  • Ralink-based RT2571 USB wifi dongle
  • Nanovision 320 x 240 TFT LCD with 4-wire resistive touchscreen
  • 2W mono speaker
  • headphone jack
  • built-in microphone
  • snooze crash bar switch
  • rotary encoder for "soft" volume control (it can be repurposed for other functions, such as a Pong-style paddle controller, by you)
  • QN8005B FM tuner
  • Freescale MMA7445 accelerometer
  • 3.3V TTL serial port, 115200, 8N1; although, you can SSH into the device, and failing that, you can plug a USB keyboard into the USB port and it will pull up a shell console, so the serial port is mostly useful for early boot debug or controlling other devices
  • Optional lithium ion battery, Fujifilm NP-120 or equivalent , 3.7V @ 1800mAh. Beware knock-offs that lack embedded battery safety circuitry or sub-par quality batteries.

Power requirements

The chumby One requires +5V, 2A DC power, regulated to better than +/-5%. The plug is a 0.9mm x 3.2mm barrel plug, although we order a 0.8mm ID plug to make sure the connection is very snug (users tend to pick up the chumby One and this can dislodge the connector).

It is fairly sensitive to line voltage regulation, so please pay attention to the regulation tolerance. Too low a voltage can trigger the brown-out detector inside the CPU and automatically cause the device to roll-over to battery usage (or to shut down if no battery is present).

The power consumption varies greatly depending upon what you are doing with the device; in particular, the battery can charge at up to 600 mA rates, and the external USB is rated to source up to 500 mA of current. Those two together can draw over 1.1A of the provisioned 2A of DC power. The remaining 0.9A is allocated to the rest of the system. Generally, the system draws about 2.5W-3W (0.5A-0.6A) when quietly playing widgets, and no battery. Note that if you are charging the battery and listening to music at the same time, the system may automatically reduce charging rate to shuffle more power into the speaker.

What's in a chumby classic?

HW 3.7 Schematic

HW 3.8 Schematic Gerbers

  • 350MHz Freescale iMX21 MC94MX21DVKN3 ARM9 controller
  • Samsung 64MB SDRAM on 32-bit data path
  • Hynix HY27US 64MB NAND Flash ROM
  • Three USB 2.0 full speed ports, one internal, two external
  • Xterasys 3135G 802.11g USB Wifi adapter (ralink chipset)
  • DataImage 320hx240v 16bpp TFT display with touchscreen
  • Texas Instruments TSC2100 Programmable Touchscreen Controller with Stereo DAC
  • 2W stereo speakers, with headphone jack
  • Built-in microphone
  • "Bend" switch
  • Kionix KXP74-1050 3-axis accelerometer
  • STMicroelectronics STR711FR0/1 ARM7 "crypto" processor
  • Soft-switch on power, controlled by crypto processor
  • TTL serial port @38400 8N1

Power requirements

The chumby uses a very standard 2.1mm I.D. x 5.5mm O.D. x 9.5mm Female (P-5) barrel connector and runs off 1A at anywhere between 6.5 VDC and 14.5 VDC.

Each Chumby ships with a "wallwart" power supply with US-style prongs; however, it's easy to find a compatible power supply with other form factors. Search on "12 volt portable power" for some options. Make sure the power supply provides at least 1 amp (1,000 MA). If you supply less than 1 amp, you'll have an unhappy Chumby that won't display properly, and might make some funny noises!

If you purchase an additional power source, you will need to match the DC power jack on the Chumby. Radio Shack's part number #274-1569 works fine as a power connector, though a tiny bit longer than the plug that comes with the Chumby. Solder the hot side to the middle of the connector, and the ground shield to the sleeve of the connector.

There is a 9 volt battery connector located in the base of the Chumby. This battery will power the unit for a short time during power outages.

Rechargeable Battery Options

In addition to a standard rechargeable 9 volt battery, the Energizer Universal Battery for picture frames (ER-PHOTO) is small enough to be inserted into the base of the Chumby after removing some of the filler material. This battery is rated at 2000mAh with tips for 9V and 12V. In casual testing it has produced up to 3 hours of normal Chumby usage, and can be used while the battery is plugged in and charging. In fact, the power cord for the ER-PHOTO battery appears to be interchangeable with the standard Chumby power adapter, so the Chumby adapter can be used to charge the battery as well.

The ER-PHOTO is available at most electronics retailers for roughly $50.

Older Prototypes

For information about alpha prototypes, please see Hacking hardware for Foo/Katamari.

NEW! Make your Chumby8 portable like a Chumby1.Add Battery power!

If you would like to be able to carry your C8 around, this should help. Photo
This hack does not require ANY modifications to your C8 and is based on the Texas Instruments PTH08080WAH adjustable switching regulator and a Sony Infolithium NP-F570 but will work with various batteries. Datasheet

To do this you need some familiarity with electronics and basic soldering skills. The PTH08080WAH is very easy to use and extremely efficient. It requires an input voltage of at least 1.1 volts higher than the desired output and will work at up to 18v input.
This battery puts out 7.2 volts and this must be dropped down to about 5v for the C8. The only additional components are a 100uf electrolytic capacitor, a 270ohm resistor and a power connector to plug into the C8 socket.
The application note contains a table of resistor values to give the required output voltage. The 270 ohm resistor gives an output voltage of about 5.1 volts.
This circuit is simple enough to be built on punched stripboard (or "aeroboard") Photo, put in a box and mounted with the battery on the back of the Chumby. Photo

A C8 draws about 940ma when displaying the "LCARS" clock and with a fully charged battery you should get about 2.5 hours running time.
The consumption would be higher if an attached USB device draws appreciable current. There is no provision for charging the battery- it should be charged in a suitable battery charger.
NOTE: Be sure to verify that the output voltage is correct. (5v +/- 5%)
Good luck.