Mystery LED in a box: part 5

see also: Mystery LED in a box: part 0
see also: Mystery LED in a box: part 1
see also: Mystery LED in a box: part 2 
see also: Mystery LED in a box: part 3
see also: Mystery LED in a box: part 4

I promised in the previous item to provide an update after my vacation. That was in August! Unfortunately my vacation doesn't take more then 3 months (I wish!). 

It took me quite some time to make the mystery box actually listen to me. I was able to tell it stuff with the IR transmitter that I had to build, but it looked pretty deaf. The last hint I got was a little assigment to tell the box 'something':

"JIPPIE NU KAN IK OOK LUISTEREN. ZEG EENS IETS..."

 I figured out that this 'something' had to be the word 'IETS', which is the dutch word for 'something'. 'IETS' has also the advantage to be fairly easy in morse code. Three dots, one dash and again three dots is all it takes (** *- ***).

Just two weeks ago I found out why me and the box were not on the same level. I made a little mistake with one of the resistors.... 3K3 IS NOT THE SAME AS 33K, IDIOT!

The 2K and 3K3 resistors serve as a voltage reference for the incoming photo transistor signal, and using a 33K resistor resulted in a 4.7V reference instead of the intended 3V.

 

Having that fixed the box and I renewed our vows and we were finally on speaking terms again. Telling 'IETS' to it with IR remote control waked it up and gave me a new sequence of morse pulses. I quickly hooked up my datalogger to log the sequence and let Matlab crunch the data:

 

"WIE ZIJN JE BESTE VRIENDEN? (IN ALFABETISCHE VOLGORDE)"

Translated: "Who are your best friends? (in alphabetical order)"

Damn, that looks like a tricky question. This really could cost (or gain) me friends... I took the safe road and picked the names of the people that actually contributed to the wedding present.

But some use their real name and others jotted down their nickname in the card. Some of the guys have actually nicknames that are used so often, their real names are already long forgotten (Bart? And who's Frank?). So multiple options here:

Regardless the right answer it promised to be a challenge to send this huge morse code sequence manually, although I realized that is exactly what they did back in the days in WW2. But then they didn't had microcontrollers like we have now so I followed Deddies Labs slogan ("Because anything deserves a microcontroller") and start putting together a morse code generator.

 

That worked! A little bird had told me in the meantime what the most likely answer was to the friends question, and finally the mystery box gave me the next morse sequence. Again twice as fast as the previous clue which was also double as fast as the one before that....
Inevitably the datalogger needed some more tuning since the last upgrade which boosted up the sampling frequency to a whopping 40Hz (!!!) proved not to be fast enough (C'mon guys, cut me some slack here). I actually compressed the data before storing it to the USB stick and decompressed it with Matlab (I will explain this later on in a different topic). It is now so freakin' fast that I myself don't even now how fast it is. I probably can expect some phonecalls from the CERN...

This clue is probably also the last clue the mystery box will give me, a running led sequence after the hint gives me the impression that its job is finished. I am shedding no tears, it is still electronics and it can't withstand salty water very well:

U'2F'UBMU'SI'G'5HY'W'KGZ'W'V'UI'H'B'VCNR'LBW'9UBMV'LI'G'1LDC'B'QDW'XSAW'U'

GBMF'TZ'W'4GZ'W'4GDH'J'VDX'DKY'X'R'1BS'4GQ'MV'3AW'PZI'H'Z'PY'S'B'IBG'9NL'I4UT

What the hell? Is this my final hint? This is not human readable. No easy "Congratulations, the present can be picked up at the trainstation in locker 1306"? Did I read the morse code right? Yes, I think I did! Did something went wrong with compressing the data or did Matlab had a bad day? Not likely.

Chuckles of recognition of some of my friends gave me definitely the idea that I got the clue right. As you all can understand, more to follow...

see also: Mystery LED in a box: part 6
see also: Mystery LED in a box: part 7 

Mystery LED in a box: part 4

see also: Mystery LED in a box: part 0
see also: Mystery LED in a box: part 1
see also: Mystery LED in a box: part 2 
see also: Mystery LED in a box: part 3

Days passed by since we fulfilled our last assignment considering the mystery LED box without any news. Did we do it right? Were we missing something? Last week the uncertainties suddenly vanished with a envelop that we found on our doormat.

In the envelop we found some interesting parts: a micro switch, an IR led, and a BP103 phototransistor. I rushed to the website we found in the previous clue and there we found a new briefing. The 'Grande Finale' was about to take of...

Again I had to add stuff to the already pretty stuffed up board and upload a new hexfile to the Attiny. I was asked to build an simple IR transmitter and giving the Attiny the capability to receive IR signals. Instead of one led the board now needed three leds.

The next evening I did my magic and a couple of hours later the mystery box was blinking again...

It started with a running light, followed by 1 minute of sequential blinking of the middle led, finished by the 3rd led turning on and off only once. Nothing after that, you could almost hear the Atmel sleeping :) In the video you can find the BP103 photo transistor in the box on the left.

Diligently I hooked up my ever so useful datalogger! Just before I started recording the new sequence like I did with the previous clues, my attention was caught by the middle led..... Damn! Rat bastards...... the sample rate of the led sequence was definitely faster then 4Hz this time and my datalogger is not capable of recording any faster. And reading the morse code with the naked eye is definitey out of question at those speeds. I knew I should have kept my mouth shut about this bug (or blog about it). Me and my big mouth!

My friends' goal was definitely to slow down the progress solving the mystery box, apparently I was going to fast for them. Now I had to (quick) fix the datalogger first. And we were about to leave for vacation in a couple of days, were I was forbidden to even think of electronics or dream of Atmels. I agreed with myself to speed up the datalogger and get at least the next clue out of the mystery box before packing my bags.

From the datalogger's sourcecode I removed everything unnecessary that could slow down the recording. Wow, I did some realy awful programming two years ago. 4 hours and a lot of deleting and rewriting later I managed to get the datalogger to record with an astonishing speed of at least 40Hz. I didn't try to make it faster, a tenfold increase seemed fine by me. I figured my friends not to be that big of assholes... Luckily I was right. After recording and some minor changes to the Matlab script the next sentence popped up:

"JIPPIE NU KAN IK OOK LUISTEREN. ZEG EENS IETS..."

Like I already suspected with the IR led and phototransistor the box was now capable of also 'listening'. It 'asked' me to say 'something' to him/it. This 'something' I still have to find out. I really have to pack my suitcases now...

As you probably already have noticed, a project like this kind of grows on you. Like my 1 year old son it finally starts to listen and I start to understand its babbling. I hope I won't mix up the two, and find myself poking a soldering iron in my son's eye while the mystery box is getting a bath.

More after my vacation...

see also: Mystery LED in a box: part 5  
see also: Mystery LED in a box: part 6
see also: Mystery LED in a box: part 7