View source for Freerunner Navigation Board v2

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Return to Freerunner Navigation Board v2.

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The second version of the Freerunner Navigation Board will include lots of new stuff to play with, while still providing the same feature set as the first version.


The FRNBv2 realizes all features from the first version on the top side of the PCB. The bottom side is all about further expansion. Most of these chips are not very usable without connecting additional electronics to them. I'll add detailed descriptions of what I did with them to this page.

Top side

3D Gyroscope ITG-3200

The new ITG-3200 digital gyroscope detects rotations and measures their angular velocity. This enables the FR to be used as game controller or to improve navigation capabilities without GPS.

3D Magnetometer HMC5843

A magnetometer senses magnetic fields. It can be used as compass for navigation purposes or to sense fields from other magnetic sources.

Air pressure/temperature sensor: BMP085

A pressure sensor can be used for weather forecast or to measure the height above sea level if the pressure at sea level is known. If the height is known from other sources (e.g. GPS), the change in ambient pressure can be used to detect weather changes. This may be useful for gliding.

Bottom side

4ch Programmable LED Controller PCA9632

This chip can source or sink current for up to four LEDs with a maximum of 25mA per LED. In addition to simple on/off states it can be programmed to blink or dim individual channels or a group of channels. Since the chip does everything on its own, it will continue to work even if the host cpu suspends. This allows the often requested feature to drain the battery even faster to notify users of incoming SMS or missed phone calls by blinking a LED even if the phone is suspended. A blink frequency down to once every 10 seconds and a widely adjustable duty cycle allows for very short flashes to save battery power.

1kHz – 68MHz Programmable oscillator LTC6904

This is, well, a programmable oscillator from which one frequency output and the output enable pin are available at testpoints. My intention was to use it as 38kHz oscillator to generate the carrier frequency of common infrared remote controls. The output enable can be connected to a GPIO. After implementing a small driver, this should work as a generic remote control solution using lirc.

12 bit Analog to Digital Converter ADS1015

This is similar to the chip which was used on the FRNBv1 to digitize analog gyroscope outputs. It provides only 12 instead of 16 bits of resolution, but this should be enough for most applications. The FRNBv2 does not use it for own purposes, so it is completely under user's control.

Touch Sensor MPR121

The MPR121 from Freescale Semiconductor is a multi channel proximity capacitive touch sensor controller. Up to twelve sensor areas could be connected, but due to space restrictions, only eight channels are accessible at solder pads. It is not guaranteed that the chip will work as intended, but I think it's worth to test it.


Schematic and board layout files are available from

Pictures of the assembled boards and more documentation (pinout, ...) will be added here.

I²C Addresses

Chip I²C address
ITG3200 0x68
HMC5843 0x1E
BMP085 0x77
PCA9632 0x60
LTC9604 0x17
ADS1015 0x42
MPR121 0x5A

Test Status

I'm testing the individual chips as I solder them to the test boards. The progress will be documented here.

  • Pressure sensor BMP085: works
  • LED controller PCA9632: works


The board will be availabe to purchase starting from the middle of august. It comes in three tastes:

  • CAB: Completely assembled board. Just add some wires and you're ready
  • DIY: Do it yourself! the PCB and all components needed to get your hands dirty
  • PCB: The bare PCB. You are free to buy only what you need.

The CAB and DIY packages miss the programmable oscillator and the analog to digital converter chips because they are rather expensive (about 6€ each, depending on order quantity) and can't be used without additional electronics. If you need their functionality it's possible to add them later on because they come in leaded packages and are hand solderable.

If people want boards containing these chips in addition to everything else I will try to add another assembly option.

Update: The PCBs arrived a few days ago. They should get assembled during the next week.

Pricing (estimates)

  • CAB: probably in the Range of 75€ to 80€
  • DIY: about 50€
  • PCB: about 7€


If you are interested, please tell me which package you'd like to purchase.

  • Example: 3x CAB including oscillator and A/D Cmair
  • 3x CAB including oscillator and A/D --Glenn 04:24, 18 July 2010 (UTC)