Power Usage

The Chumby Hacker board doesn't take a lot of power on its own but adding goodies can really boost up the draw, here are some things to look out for.
  • The main system itself (processor, RAM, SD card) draws 200 to 300 mA depending on how hard its thinking
  • The USB hub draws 100-200mA (not including power to the USB devices) depending on how many ports are active
  • Having a speaker plugged into the 2W output adds as much as 300mA (louder speakers = more current draw)
  • Charging an attached Lipoly battery will take another 500mA max
  • Plug-in LCD (we dont have one yet but say it existed) will draw 100-200mA depending on make and backlight brightness

Power Jack

The Hackerboard requires a regulated 5VDC power supply, positive tip, via a 3.5mm OD, 1.4mm ID barrel jack (sometimes referred to as a 3.8mm or 4mm connector). To connect you will need a matching plug, such as this . We suggest a regulated switching supply with over 1000mA output capability. The power required by the board itself is not that high (see above) but if you plug in a Wifi dongle into the USB port, or an LCD into the LCD expansion port, the power required can easy climb to a 1000 mA. Since the connector is the same as those used in the PSP, you can use a PSP charger

Under no circumstances should you power the device with anything higher than 5V, you will destroy it!

Lithium Battery

The board can also use a standard 3.7-4.2V lithium ion/polymer battery for power. The board even has a built-in lipoly charger! It is activated by default and if you plug in a Lipoly battery you'll see the kernel recognize it and start charging at up to 500mA.

The Lipoly breakout is a JST B3B-EH-A connector on the same side as the power and A/V jack, next to the single USB port. To connect, use a 0.1" or 2.5mm spaced female socket - the official one is JST EHR-3 and crimp the matchingcrimps on a red, yellow/white and black wire (28 AWG, stranded is best). Slip in the crimped wires so that the board markings match up such that red is +, T is yellow, and - is black. The markings are on the opposite side of the PCB
If your battery does not have a temperature output, you can simply solder a 10K resistor between yellow (temp wire) and black (ground). You'll probably not need a temperature sensor but in case you do, use a 10K NTC.

If powering from a lipoly, the chip will boost it to 5V to supply power to one of the USB ports (the top one, on the same side as the power jack) but not to the other two. There is a fourth USB connection on the header where I2C and other DIO pins are - this one IS also powered by the lipoly boost system.

The lipoly is also used for the RTC backup! Any lipoly battery, when charged, will let the RTC run for years.

This guide was first published on Dec 12, 2012. It was last updated on Mar 08, 2024.

This page (Power) was last updated on Oct 23, 2012.

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