Thursday, January 7, 2010


Freescale announced this week their latest accelerometer MMA7660FC. This is a 3-axis digital output (I2C), very low power, low profile capacitive micro machined accelerometer featuring a low pass filter, compensation for 0g offset and gain errors, and conversion to 6-bit digital values at a user configurable output data rate. It offers low-power operation of 47 µA at 1 sample per second. The device can be used for sensor data changes, product orientation, and gesture detection through an interrupt pin.


The product description ends with: "The device is housed in an extremely small 3 mm x 3 mm x 0.9 mm DFN package."


Elektor will present very soon its mobile 32-bit platform Sceptre which includes, amongst others, a 3D accelerometer from Freescale. For the Sceptre I have spent a lot of time looking for hand-solderable accelerometers but without success. Do easy to solder accelerometers actually exist? I guess not, but maybe someone will know of one and tell me about it. A more useful question is probably:

Do you have a technique for reliably soldering QFN or DFN packages by hand?

This question interests me very much, and, I am sure, many other people as well.

Here is a picture of the Sceptre that I sneaked out of the lab.
Hot, hot, hot!!!

This is one of the first three prototypes and it still works (one died during temperature testing). A second version that fixes some bugs and adds some improvements is on its way.

The accelerometer is the little black square in the left lower corner of the board (its a QFN unfortunately). On the top right is a Bluetooth module and if you look well enough you can see on the left an SD card sticking out from the bottom of the card. It runs from a mobile phone batterie and a charger for it is included on the board.

Stay tuned!

Freescale accelerometer MMA7660FC


  1. Since the accelerometer is almost always a secondary function of the device, and is increasingly being integrated into compact, mobile devices, the footprint of the device is probably a larger contributer to the integration cost than the actual device cost, for most users.

    Given how recently accelerometers were developed, they started small and will only get smaller.

    For experimenters, it would be very cool if some helpful company produced a small board with the accelerometer SMT mounted and either some pins (DIP) or possibly just some edge pads that could be easily soldered into early design prototypes.

    On the other hand, it's only a matter of time before MCU designers start including the accelerometer on-chip. Actually, that's probably just a pipe dream, since it is already a challenge to get mixed-signal, flash and EEPROM on the same die, let alone MEMS.

  2. The company Memsic has some hand-solderable accelerometers. For example the 3-axis MXR9500MZ but their products are lot expensive then those from Freescale (€16,88 v.s. €5,68).
    Memsic made it possible to solder a header on the copperfields at eache side of the accelerometer. They're availeble at Good luck!

  3. Also Measurement Specialities has some solderable triaxial accelerometers. However these are highly expensive (hundreds of dollars each).