Today my sister had her commencement! What a cheerful day! Here’s a photo of my sister giving the commencement speech:
Congrats, she did a really good job. All in all it was a great day: great weather, lots of nice people, lots of good food.
Long time no see! Sorry, I was pretty busy. I still am, but hey once in a while you gotta take a break!
This week was home improvement week, some repairs here and there, new glass walls in my kitchen, and because Andrea always reminds me that my apartment looks to much like a guy’s place (no decoration and stuff) we decided what to do with the big plain wall in the entrance area. We ended up painting the German word “Willkommen!” and the English translation “Welcome!” onto the wall in big, orange letters (1 m=3.5 feet length!). Here’s photo of the result
… and another one with my sister, her boyfriend, another friend of hers and Richard. Notice of the self-made fruits picture in the back!
Lots of decoration work is still to come! Hope that we can “Welcome!” some of you soon, so that you can take a real life look at our pieces of art!
I proudly announce: my little sister finally graduated from law school on Friday! And I am sooo proud of her! She did not allow me to take photos before the final exam, but here’s a relaxed one right after the exam with her sipping champagne.
I really enjoy having her as a sister.
I mean it was not always easy and we certainly had our share of fist fighting. I think that is just how it should be between sister and brother. However I guess we both can say that we are pretty glad we have each other! And while we both work on building our own lives we there are still bonds.
So just a kind warning: Don’t mess with me, I’ve got a good lawyer now! ;)
Log time no see. First of all I’d like to wish you all the best for the new year. Here’s a photo that I made to share my Christmas wishes!
Christmas, as always was about the busiest time of the year. Parties everywhere, finishing up this year’s stuff at work, all the last minute things that you could have done long before …
But then came the long awaited Christmas holidays. Time to relax a little bit, read books, come up with good new year’s resolutions and do the things that you would usually not have time for.
There’s one holiday project in particular that I’d like to show to you:
I had a lot of fun doing that and really enjoyed the time of late night programming that the holidays allowed me to take. It would be great to hear from you what you think about it. If anyone wants such a system too, I can help you set it up, just drop me a line!
Meanwhile I wish you all the best for 2011 and keep on rocking!
I use my TI chronos watch to control my bedroom light. This post contains information on how the whole thing evolved and how it works. To get a rough idea about the project you might want to watch the short video below.
Table of Contents
1. Introduction
1.1 The Story Behind the Project
1.2 The Hardware
2. Reverse Engineering the Communication
3. TI SmartRF Studio
4. Code Composer Studio: C Code
1. Introduction
1.1 The Story Behind the Project
I installed a dimmer in my bedroom about a year ago. It comes with a remote control that allows you to switch the light on and off, as well as to dim the light. About two month ago ordered the TI chronos.
Hey wait a minute: They both operate at 868 MHz. So it should be possible to make the TI chronos control the dimmer. Well, the idea was born, now it was time to knuckle down ;)
1.2 The Hardware
This project combines
- the TI chronos (http://www.ti.com/chronos)
- and a dimmer from Conrad Electronics /http://www.conrad.at/ce/de/product/620587/Funk-Lichtschalter-mit-Sender).
The TI chronos comes with a very detailed documentation and also Conrad even provides a schematics for the dimmer (Click links below).
The dimmer comes with a remote control which allows to switch light on and off. If the button on the remote is held down, instead of pressed just once, the brightness can be adjusted.
2. Reverse Engineering the Communication
The goal is to emulate the signals sent by the remote control with the TI chronos watch. Therefore the first step is to characterize the RF signal transmitted by the remote control. The problem can be tackle using two approaches. One can either try and understand the schematics provided above or one can perform measurements. The schematic has one flaw, that is it does not describe the RF module, so no information about the modulation scheme, packet format and so on.
Thus I went with the measurements first. A session at the spectrum analyzer and a 10 GS/s oscilloscope soon showed the commands are sent using OOK (On/Off shift keying) at a carrier frequency of 868.35 MHz. The signal that goes into the RF module simply turns an SAW oscillator on and off. The chip that is used to generate the transmit data is a HT12E encoder (http://www.holtek.com/english/docum/consumer/2_12e.htm). As long as the button is pressed the encoder generates a signal that is repeated periodically. The following figures show the signal as measured with an oscilloscope.
It turned out that a minimum of 6 code cycles are required for the dimmer to switch the light on and off. If more code cycles are transmitted the brightness starts to change.
The exact code generated by the encoder is hardwired into the remote control by soldering, as can be seen below (click to enlarge).
The last four bits are always zero but the first eight bits are set by soldering at the encoder’s pins. The encoder prepends a zero and then generates a stream of three bits for every single input bit (a total of 3+8*3+4*3=39 bits) which are then transmitted by the TX module (see oscilloscope plots above and, which matches the code of the remote in the photo). I now even have two dimmers in my apartment, no measurements were required for the second dimmer, as the code can be read from the soldering.
Click here to download a zip file that contains measurement data and MATLAB code to extract the data to be sent by the TI chronos. Simply run “runDataExtraction.m”. “runEncodeData.m” will produce the hex code for a given solder mask.
3. TI SmartRF Studio
Now it is time to test the code obtained from 2. Reverse Engineering the Communication with the TI chronos to see weather it works or not. I just connected the chronos to the computer via the debug interface and started TI SmartRF Studio (http://focus.ti.com/docs/toolsw/folders/print/smartrftm-studio.html)
First I used the “Packet TX” mode, after adjusting all the required RF settings suddenly, like magic, the light turned on and off. In a next step I tried the “RF Device Commands” mode. This is a little bit trickier, you have to set all the strobes yourself. At first it did not work as I never used the FSCAL strob, but then I found the following routine to be working:
1. Initialize register settings: Press “Pkt TX” button
2. Set the RF parameters to your requirements, in my case (click to enlarge):
3. Write TX FIFO (Write data to TX FIFO)
4. SCAL Strobe (Calibrate PLL)
5. STX Strobe (Transmit the command)
Tada, the light goes on or off every time STX strobe is set. After the first run, you can skip 1 and 2, just loop 3-4. Now it was time to export the register settings for the C code to be implemented in 4. Code Composer Studio: C Code, so I enabled the register view and used the “Register Export” feature. Which format works best for you depends on how you write your C program.
4. Code Composer Studio: C Code
What can I say, here’s the complete source code: download source code.
First of all, what are the changes from a user point of view: Compared to the original software there’s not much of a change, only two things: The primary first (L1) and second line (L2) modules (the ones that show the time and the date) loose their secondary view mode. So the up and down keys will no longer show the seconds or the year. But come on: Who needs to know what year it is, or the exact second. Instead these buttons will cause the two codes for my two dimmers to be transmitted.
Now to the code point of view: The two new files are cSLight.c and cSLight.c. Actually they implement another L2 mode. But I did not activate it, as modifying the buttons for the two main L1 and L2 modes seemed a better idea. Besides the obvious things needed to implement the L2 mode and to modify the main L2 and L2 modes I changed the Strobe function in rf1a.c. I don’t know if it is actually needed, but I found more recent CC430 rf1a code on the TI website, which actually seemed more reasonable – so I replaced the function that comes with the chronos.
While a lot is happening at work - for those you who do care: the 77-GHz VCO and the PLL seem to lock! - spare time is fun too! Here’s a photo of the party people before we went to the dace last Saturday:
Thank you Markus for not letting me alone, I enjoyed your company. On Monday I joined the people of my old dorm for the annual wine tasting. The vintner was there himself to present some of his best wines! And it was good to see all these great people, its amazing how we all evolve and still stay the same somehow. I had some great conversations with Rene, Severin, Martina, Lukas, Elisa, Richard …
Tonight is a little bit more calm. Just a nice glass of wheat beer with my roomie Richard!
I do work a lot right now, but it is important to save these nice moments where you give yourself a break!
This week was big socializing week. Monday night I attended a panel discussion with Landeshauptmann Pühringer at the KHG Heim Linz, which was pretty interesting. Tuesday evening was the Mechatroniker Stammtisch where I got to talk to some old friends that I hadn’t talked to in ages.
Wednesday was the IEEE Student Branch, JKU Linz excursion to ZIZALA Lichtsysteme (www.zkw.at). That really was a highlight. For starters I guess I just like the people in our group so much! They are such a great bunch people who are motivated, eager to explore, committed, a lot of fun …
The food was also awesome! Here’s a photo of the CEO of ZIZALA and our group:
It did not end there! Thursday night some colleagues and I decided to give the new Schnitzelhaus around the corner a try. To not get an overly guilty conscience because of the fat food all the time I had to go for a “Schnitzelhaus run” first (http://www.sports-tracker.com/#/workout/chschmid/aooetr4u9gakg2ev) but finally we did it. That the three of us at the Schnitzelhaus:
Well, guess what it did not end there either, yesterday my friend Hari came by to work on his website (www.haribaumgartner.com) and later I had a rehearsal with our wind band (which did not work out, as some just didn’t show up). Today was IEEE Austria section proposal writing day, and I hope that I can clear out my head by running before I’ll go to a dance with Andrea and some friends of hers tonight …
While socializing can be rewarding it can also be pretty exhausting sometimes, I’m really looking forward to an evening of just … well … nothing …
Johanna and Monika, two sisters of Andrea are in Mexiko right now. They really seem to enjoy it. However despite all the fun, new experiences, beaches, sun … Johanna misses one thing: Pickles! It sounds crazy, but that is what she seems to miss the most. So Andrea and me, we use the web to send them this virtual pickle:
Just make sure you don’t eat it all at once ;)
It’s a beloved tradition. Once every year we have our fall concert with the Trachtenkappelle Thalheim - a wind band consisting of a bunch of frenetic amateur musicians, such as myself. Some every-Friday rehearsals
led to the final event
I couldn’t resist the temptation to take some pics while the moderator was talking ;) The audience (some 300 people) seemed to like the concert
and so we are all glad and thankful for that wonderful evening. A personal highlight for me was that Andrea and ever her parents came to listen. Thank you and thanks to all of my fellow musicians for their efforts!
Being part of the Herbstkonzert 2010 of the Trachtenkapelle Thalheim is a once in a lifetime event! But for all of you who couldn’t make it, one year from now, another concert is waiting for us!
A lot has happened this week, and while crap keeps piling up on one end it is worth while to become aware of the good things that just don’t stop happening on the other end. Tuesday night was engineering night, the Mechatroniker Stammtsich took place at the KHG Kellerbar, so let me introduce to you, the future of engineering!
Both pics are a little blurry, but I guess that’s because these people are so dynamic and energetic! It was the perfect occasion to grab some beer and some pizza with Kurt, David and Daniel! I just couldn’t believe it when Kurt pulled out some Snaps!!! He told me it’s important to have something at hand to warm yourself as winter approaches.
Let me tell you, these people really know how to rock! I just made one mistake, I did not stop there, but went to Wolfi’s birthday party after KHG Kellerbar. I gotta admit: I’m getting too old for that stuff, coming home at 4 am I gave my body a really hard time! Talking about seeing good friends: This weekend was heavily music burdened. We had a lot of rehearsals with our local wind band, and one thing that I am especially happy about is that I had the chance to make some music with my best friend Birgit from Salzburg. We did some songs for the christening of one of her nephews. I just love her voice, I will never get it why she did not go into studying music!
Also meet her wonderful daughter Fiona:
I guess it’s enough now for this “people’s post”. Thank you everybody for being part of it!