My application:
I am currently an electronic engineering student in London, looking for a suitable device for 2-axis tilt measurement in a control system project. Job offers in June 2012 greatly appreciated.
What do you get:
I received 2 nice CD-sized boxes with documentation and components. The hardware components were individually wrapped in bubblewrap and seemed well protected.
The documentation included packing lists so I am confident I got everything, a tech support card, a warranty registration card, and a 2 page full colour quick start guide with very clear identification photos.
The hardware received was a suitable USB cable, the larger LFSTBUSB board which sits on the bottom, the MMA845X interface board which plugs into the top of the USB board, and 3 breakout board DIPs with 3 different accelerometers that plug into the top of the interface board.
The three accelerometers represent the MMA845xQ family:
- MMA8451QTMMA8451QT - a 14 bit accelerometer
- MMA8452QTMMA8452QT - a 12 bit accelerometer
- MMA8453QTMMA8453QT - a 10 bit accelerometer
The boards are clearly well made. The USB board is even pre-fitted with plastic standoffs as legs which is a nice touch. There are clear markings for pin 1 for each connection so it would be very hard to make a mistake. After assembly you end up with a three layer stack.
Getting the software:
After unpacking and assembly, the first step is to download and install the Sensor Toolbox software from Freescale (www.freescale.com/sensortoolbox). They offer lots of different sensor dev boards including magnetic, pressure and touch, in addition to acceleration, but there is just one software download that covers all of them. This certainly makes things easy. The download is 31.4 MB in size. I got Public Version 4.2.0.3. There are no system requirements published anywhere I could find, but it is Windows only. I am using Vista and have had no problems so I assume it will work fine with Windows 7 as well. Windows XP? No idea.
Whilst waiting for the download I noticed some training videos on the download page. The "Quick Start Guide" video can be found here: http://youtu.be/chqVx6niK4s
Running the software:
After installation completed, the Sensor Toolbox software started automatically. I hadn't at this point plugged the boards into the PC and a small message appeared in the splash screen asking me to do so. I did that and nothing happened, so I turned the board on using the switch on the USB board. I got a bright red light and Vista said it was installing a driver, but nothing further happened. I restarted the software and got the same result. Hmmm. At this point I thought maybe I needed to install the FTDI driver as well. The installation program had offered it as an option but it had been de-selected so I had assumed I did not need to do this. Fortunately a link to the FTDI driver installation is created for you in the Start menu. After this completed, I restarted the Sensor Toolbox software and it worked fine, and has continued to do so.
The software starts with a screen offering 8 options. I have tried the first, the Full System Evaluation. This Freescale video shows this software (albeit a slightly different layout, and for a different accelerometer) in operation: http://youtu.be/8NNu2S4PMeM
Using the software I can see quite clearly the accelerometer responding to any movements I make. On the main screen it offers the ability to adjust the number of bits, the G level, the sampling rate, offset calibrations, and a high pass filter setting.
Conclusion:
I now have to explore the software in more detail and try the 3 different accelerometer models to see how they differ in their response, so as to try to understand which one is most suitable for my application. This would be much more difficult with out the Sensor Toolbox software and I have no hesitation in recommending it for people interesting in understanding and evaluating accelerometers, even those first time users like myself. I am happy to answer any questions you may have.
