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Archive for the ‘TKJ Electronics’ Category

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 331 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: http://www.tkjelectronics.dk/uploads/Kalman_SRP.zip. 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.
Read more…

Categories: Guides, TKJ Electronics Tags:

Wiimote added to USB Host library

August 21st, 2012 72 comments

This is yet again a new announcement regarding the USB Host library. I just added support for the Wiimote via Bluetooth.
Check out the source code at github: https://github.com/felis/USB_Host_Shield_2.0/blob/master/Wii.cpp and the example sketch as well.
I will work on implementing support for the Nunchuck and Wii Motion Plus extension in the near future.

Update:
The library now also supports the Nunchuck controller and the Motion Plus extensions. The newest version of the library can be found at github.

Another Update:
The library now also work with the new Wiimote where the Motion Plus extension is built-in.
Check out my commit to see what where needed in order to make the new Wiimote work as well – the main difference is that you now have to send the data using the interrupt channel.
To tell if your Wiimote is the new type, it should have a label at the bottom saying “Wii MotionPlus INSIDE”. If you are in doubt take a look at this picture.

Yet another update:
The IR camera inside the Wiimote is now also supported. The the following commit for more information.

A new update once again:
The Wii U Pro Controller is now also supported via Bluetooth.

Categories: Arduino, Bluetooth, TKJ Electronics, USB Tags:

Stellaris Multimedia streaming client

August 9th, 2012 No comments

Some of you might already have seen and read about the Multimedia streaming client project we posted as a video a couple of weeks ago. Though for you who haven’t here comes a description.

The Multimedia Streaming Client in action


Back in May we were kindly given some of MikroElektronika’s latest ARM development tools and decided that we would make a big and time consuming project with it.
As we started planning the project we had no ideas at all but all of a sudden the idea of a Multimedia streaming client struck my head. Why not use the on board VS1053 Audio codec chip for music playback and then use the Ethernet port to add a streaming functionality.
Read more…

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Xbox 360 controller support added to the USB Host Library

July 18th, 2012 88 comments

Update
A wireless Xbox 360 controller is now also supported via a Wireless receiver. For more information see the blog post.

Hi everyone. I just wanted to let you know, that I just added support for the Xbox 360 controller via USB to the USB Host Library. The code can as always be found at github: https://github.com/TKJElectronics/USB_Host_Shield_2.0.

Categories: Arduino, TKJ Electronics, USB Tags:

NXT Shield Library

April 18th, 2012 5 comments

After several questions on how to use the NXT Shield I decided to create an Arduino library. All the code is available at github: https://github.com/TKJElectronics/NXTShield.
The library is pretty easy to use, I have provided three examples witch demonstrates all the libraries functionalities.

I works with all official Arduinos including Arduino Mega. To use the ultrasonic sensor with an Arduino Mega, one have to connect pin 20 (SDA) to A4 and pin 21 (SCL) to A5. A new revision of the shield might use the two extra SDA and SCL pins that are near to the AREF pin on r3 versions of the new Arduino boards.

Below are some photos of the NXT Shield:
Read more…

QuadCopters – How to get started

March 27th, 2012 143 comments

I have been watching different videos of QuadCopters recently and I’ve been pretty amused. The way they fly and the way they control their movements is unbelievable – it almost looks like a bug.

If you don’t know what a QuadCopter is, you should definitely have a look at the video below where some advanced features of cooperating Quadcopters are displayed:

So I decided to start reading some more about the materials behind these QuadCopters and how they manage to stabilize in the air.

In this blog post I will try to describe the different steps I have been thru to plan, design and build the prototype of my QuadCopter. There will be coming some more blog posts later on describing how to get the QuadCopter running, programming it, tuning it etc.

This blog post is divided into 3 parts

  1. What is a QuadCopter
    1. Brushless motors
    2. Propellers
    3. Roll, Pitch and Yaw
    4. ESC – Electronic Speed Controller
    5. Battery
    6. The frame
    7. Frame configuration
    8. Inertial Measurement Unit
    9. Controller electronics
  2. Initial decisions
    1. Theoretical calculator
  3. Conclusion

Read more…

Categories: Guides, Multirotors, TKJ Electronics Tags:

ATtinyRemote

March 20th, 2012 70 comments

I have previous thought about buying a universal remote like this one, as I was tired of grabbing my JVC remote for my stereo everytime I had to turn it on, off or turn the volume up or down. But then I discovered Ken Shirriff’s IR Library for the Arduino. Normally the library didn’t support neither the Panasonic or JVC protocol, but I discovered that somebody else had already added them. See the forked github library. At first I simple downloaded the library and tested whenever it could decode the Panasonic protocol and send commands to my JVC stereo. It had to tweak the library a bit, but then it worked just fine.
I thought it would be a bit overkill to use an Arduino and I didn’t want to rewrite the whole library, so I decided to use another AVR’s but in a much smaller package, the ATtiny85. Which is 8-pin AVR.
Read more…

Categories: Arduino, Guides, TKJ Electronics Tags:

The Balancing Robot

March 4th, 2012 599 comments

Now avaliable as a kit
A balancing robot kit is now avaliable via Kickstarter: http://www.kickstarter.com/projects/tkjelectronics/balanduino-balancing-robot-kit. Check out the blog post as well: http://blog.tkjelectronics.dk/2013/03/balanduino-balancing-robot-kit-kickstarter/.

Hello everybody
I have for a long time wanted to build a remote controllable balancing robot aka Segway – that’s was actually the main reason why I created the PS3 Bluetooth Library both for Arduino and the FEZ Devices. It has been a long time since the sneak peak and the performance has been improved a lot since then. The original one had a FEZ Rhino as the main processor, but I discovered that it was not fast enough to read the encoders, as it is not running embedded code. Also I was already using more than 10ms per loop, which I used as a fixed time loop, so I decided to step up a notch and go for a much more powerful device: the mbed microcontroller, which is an ARM Cortex-M3 running 96MHz.

It might have been possible with just a normal Arduino (NB: I have now ported the code to Arduino, see update for the code), but I didn’t want the speed of the processor to be an issue, so I decided to go for the mbed. The robot also features an Arduino Duemilanove with a USB Host Shield on top running a sketch based on my PS3 Bluetooth Library. The mbed board actually has USB Host functionality, but I decided not to port the PS3 Bluetooth Library as my original thought were to use an Arduino Due, but as you might know it hasn’t been released yet, despite the Arduino team announced, that it would be released by the end of 2011. But as soon as it is released I think I will port the code to it instead.

Video Demonstration
Here is a short video demonstration of the robot and me explaining some of the concepts of the design and how it works:
[youtube=http://www.youtube.com/watch?v=N28C_JqVhGU]
Read more…

Giving away 6 free CeBIT eTickets

February 28th, 2012 No comments

Are you going to CeBIT 2012 but are still missing the tickets?
We have been given quite an amount of tickets from different vendors. So we would like to see you there too and would therefor like to offer you a free ticket (?34 normally).

If you are interested in this limited offer please send us an email at: mail@tkjelectronics.dk
The tickets will be given on a first serve basis.

Categories: TKJ Electronics Tags: