As a part of my electronic engineering degree I have decided to look into the world of Software Defined Radios, a complicated but very powerful tool.
Software Defined Radios, SDR in short, is in short a software-based radio platform, making it possible to program the RF transmissions schemes and updating them on the fly if necessary, a bit similar to what we in the digital world know as FPGA’s. This allows end-products to redefine their radio needs, such as when sending a satellite into orbit where it would be impossible to update the RF hardware platform to support other radio protocol and schemes.
USRP N200 module
To get familiar with the SDR’s I decided to work with a basic USRP N200 module which is supported by LabVIEW and other tools, eg. GNU Radio, and write a detailed report about my progress and discoveries (see the bottom of the post for a link to the report).
The N200 module is controlled over an Ethernet interface, which is also used to exchange (transmit and receive) the so called IQ samples when they have been converted by the analog RF frontend.
In the video below I demonstrate the use of a Software-Defined radio setup with two USRP N200 modules programmed in LabVIEW programmed with an AM modulation and demodulation scheme.
The modules are programmed and tested thru LabVIEW where a graphical interface allows me to transmit a single tone signals or an audio-file from one SDR unit to another for.
I would really recommend anyone that is interested in this sort of thing to read through it for a deeper understanding on the fundamental theory and how it is implemented on a flight controller in practice.
It consists of three parts. The first part presents a theoretical model and the equations used to estimate the attitude and altitude of the quadcopter. The second part describes how the system is implemented on the microcontroller and lists the hardware used for the project.
The final part measures the performance of the flight controller by logging the data in real time. This data is then compared to the simulated results based on a theoretical model simulated using Simulink.
In total there are four different flight modes supported by the flight controller. The first one is acro/rate mode, which only uses the gyroscope to stabilise the quadcopter. This mode is mainly used for advanced pilots and acrobatic manoeuvres. In this mode the aileron and elevator stick inputs indicate the desired rotation rate of the quadcopter. Thus, if the user wants the quadcopter to rotate fast clockwise along its roll axis the aileron input can be put all the way to the right.
In this blog post I will describe a IoT (Internet of Things) Vending Machine that I built quite some time ago with a friend of mine Sigurd Jervelund Hansen.
At Sigurd’s dorm room they got hold of an old vending machine free of charge, as it did not work. We quickly decided that we wanted to get it working and give it a overhaul as well. In the end we enabled it to take both RFID/NFC cards and coins and make funny twitter updates about it.
The video below gives a short overview on how it works.
As mentioned we reused some shift registers, relays and voltage regulators on the original mainboard. One Arduino Pro Mini is connected to the mainboard and takes care of reading and lighting up the buttons (lights up if the relevant slot is not empty), controls the 7-segment LED display, reading the output from the coin validator and returning money if the user requests it by pressing a dedicated button.
As some of you might know I have been studying in San Francisco the last semester at San Francisco State University. For that reason I have not done as much as development as I usually do, due to all my equipment being back in Denmark and also because I prioritised being social and not just sit behind my desk coding all night 😉
Anyway I did not fully stop working. I actually started working on my own flight controller written from scratch in one of by courses. Below is the result so far:
To make our robots even more autonomous we would like to investigate the world of Laser range finding using LIDAR technology. Unfortunately for the users who want to try out LIDAR it’s a very expensive technology to get your hands on.
Throughout the years though Vacuum Clearner robots have evolved a lot, both in the algorithms gettings better but also in the use of more advanced sensors. Lately the Neato XV-11 All Floor Robotic Vacuum System included a small range (0.2m to 6m) LIDAR with 1 degree precision and a resolution of a couple of centimeters. As this vacuum cleaner only costs around $400 makes it a bargain to get hold of a LIDAR if just you could disassemble the robot and use just the LIDAR.
Internet of Things (IoT) is one of the big electronics subjects throughout the world this year.
To show the capabilities of custom IoT devices and to help a local LAN-event organisation, TheBlast, we offered the help to create an Internet enabled soccer table.
Thanks to generous donation by Tuborg Fonden we were able to buy a brand new soccer table for us to modify.
We modified the table by adding two touch displays for user interaction, a barcode scanner for user registration. Inside the table we installed two score detection IR sensors and a ball release system, made by using a motor/wheel from an old Roomba robot. Finally we installed 5 meter of RGB LED strip to light up the playfield.
When scores is detected they are immediately registered online, to be displayed on the LAN-event website, where score timetable and all previous matches can be found.
This post will describe the features of the final table and how it was developed.
It has been quite a while since my last blog post, but I am finally ready to reveal what I have been working on the last months. Ever since I made my first balancing robot: http://blog.tkjelectronics.dk/2012/03/the-balancing-robot/ and the Balanduino I wanted to build myself a full size version which I would be able to ride just like a regular Segway.
Finally I decided to make one together with a good friend of mine Mads Friis Bornebusch in a course at my university DTU (Danish Technical University/Technical University of Denmark).
The main frame is an aluminium checker plate that is 500x360x7mm which the motors are bolted onto. This width was chosen, so it would be able to go through a normal door opening. The motors used are two MY1020Z 500W, 24V, 12.6Nm brushed DC motors.
I ordered them from Germany, as I needed them right away, but you should be able to get them much cheaper by ordering them directly from China.
Below is an image of the aluminium checker plate after we have drilled the holes for the 8mm steel bolts. Note that these are countersunk, so they are flush with the surface. I would recommend using lock nuts to ensure that the bolts will stay in place – you can also use Loctite instead.
Aluminium checker plate – ready to mount the motors
After some great success with the USB Host shield development and the sales of the USB Host shield for Arduino thru our webshop, we are happy to announce that we have also started carrying the compact version of the shield, the USB Host Shield for Arduino Pro Mini.
USB Host Shield for Arduino Pro Mini
The shield is just a compact version of the well known USB Host shield for Arduino’s and it makes you able to add the USB Host functionality such as Bluetooth control with PS3, Wii or your Android phone, to any Arduino Pro Mini equipped projects. Please note that your Arduino Pro Mini must be running 3.3V though!
We will be selling the mini shield at an introductory price of $20.00 USD and it can be bought including pre-cut headers for stacking.
A lot of you probably both know the STM32 devices maybe even from our blog as we tend to use it a lot. You probably also know the mbed board that started as an NXP LPC1768 equipped microprocessor development DIP-like module.
Now ST Microelectronics has decided to join the adventure of the mbed world by making their own mbed development board series and adding support for 4 different STM32 devices in the mbed online compiler environment!
We are happy to announce a new contributor and hopefully soon consultant at TKJ Electronics, Diego Ayala.
I have been in touch with Diego for quite a while and we have been talking about his experience with the STM32 family and other ARM M0, M1 and M4 cores together with the Keil and CooCox IDE’s. So an experience like his is really usefull for ARM embedded projects.
To display some of his work we decided to go thru one of his recent projects, a color tracking device running on the STM32F103. A project that really displays what the ARM Cortex-M3 device is capable of doing, as long as you optimize well enough.