Archive for September, 2012

Cortex-M4 and 9DOF for $10

September 14th, 2012 12 comments

Soon to be released is the new STM32 F3 Discovery Kit from ST Microelectronics.

This board features their new STM32F3 microprocessor with a Cortex-M4 core running up to 144MHz together with an FPU and a DSP that was announced back in June.

STM32 F3 Discovery Kit

The exciting news about this upcoming board is the on board features as the board will contain a 3-axis gyroscope (L3GD20) and a 6-axis e-compass consisting of a 3-axis accelerometer and a 3-axis magnetometer (LSM303DLHC).

As the board is supposed to be priced around $10 this will make an extremely low cost AHRS system with plenty of processing power to do the DCM math algorithm together with PID loops and other tasks.

Via ST Microelectronics

Categories: TKJ Electronics Tags:

A practical approach to Kalman filter and how to implement it

September 10th, 2012 309 comments

I have for a long time been interrested in Kalman filers and how they work, I also used a Kalman filter for my Balancing robot, but I never explained how it actually was implemented. Actually I had never taken the time to sit down with a pen and a piece of paper and try to do the math by myself, so I actually did not know how it was implemented.
It turned out to be a good thing, as I actually discovered a mistake in the original code, but I will get back to that later.

I actually wrote about the Kalman filter as my master assignment in high school back in December 2011. But I only used the Kalman filter to calculate the true voltage of a DC signal modulated by known Gaussian white noise. My assignment can be found in the following zip file: It is in danish, but you can properly use google translate to translate some of it. If you got any specific questions regarding the assignment, then ask in the comments below.

Okay, but back to the subject. As I sad I had never taken the time to sit down and do the math regarding the Kalman filter based on an accelerometer and a gyroscope. It was not as hard as I expected, but I must confess that I still have not studied the deeper theory behind, on why it actually works. But for me, and most people out there, I am more interrested in implementing the filter, than in the deeper theory behind and why the equations works.
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Categories: Guides, TKJ Electronics Tags:

Raspberry Pi GPIO control

September 8th, 2012 13 comments

We have been working with the new Raspberry Pi board for a while but didn’t show it to you guys before now.
Many of you might already have seen and read plenty of videos and articles about it so I thought it would be more appropriate to make a tutorial on how to use the GPIO’s, and especially on how to speed up the GPIO’s.

In this video I walk you thru all the steps from installing the Raspbian image which is based upon Debian. This is by far the most complete and well working image I’ve discovered.
Together with a complete X-window system it also comes with many different developer tools preinstalled such as Python and GCC.

So go watch the video while to set up your own Raspberry Pi for GPIO control.

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