There is an old Hungarian saying: ‘A puding próbája az evés’. That is, the only way to see if your pudding (as in dish) is any good, is to eat it. Well, we had our very long, very detailed pudding (as in dessert) today, and it was great! And believe me, we went down to the bottom!

Finally got the gadget to work. Tested against the results I managed to get earlier, and it seems to hold.

Since I am just about to finish this project (well, at least, time is up), it’s worth taking a look back: After fixing some experimental design issues, I got some wacky results. “Now that’s strange” I thought, and remained quite sceptical. It seemed so unrealistic, as the hypothesis was so straightforward that I was convincing that I will get the boring results everyone expected.

The results were nothing like it when I make the processing routines of course. What do you do in that case? You immediately assume that you have made a mistake at some point, and you have a list of suspected things you think might be held responsible. However, the results held against my every attempt to prove them inconsistent/wrong, and believe me, Jenny’s ‘vicious reviewer’ comments and my critical thinking made us to examine things thoroughly and systematically eliminate every factor that might have explained what we have seen or measured.

Today, I can say, that this three-week-long full-blown crusade against errors, mistakes and misinterpretations has failed. Going through thousands of measurements, quite a few display devices and even creating and using a purpose-built visual device (I couldn’t find an other name for it) have failed to do any harm to the credibility of the results.

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After some fiddling with the code, the circuit works. Delays seem to be fine. Results seem to be fine. Found out how to control the serial port. I should upload some shell scripts to make life easier when using a campus pc. I managed to cover up the effect of the earth loops, so the circuit is stabilised properly.

Now, it’s on to matlab, and will need to spend time thinking about the implementation.

Things now slow down a bit. I expected much more rapid progress with the micro. There were some obstacles that should not have been obstacles: The default reset value for an output pin is analogue input (took a good 3-4 hours to find out). My new USB/TTL UART doesn’t have the CTS/RTS pins wired internally to the power supply, so I can’t bypass flow control that easily (2-3 hours). The battery lasts around 5 hours in the oscilloscope (2×1 hour break). The poor thing sometimes re-sets because of interference. This will be solved as soon as I get rid of all the earth loops caused by the programmer, the UART and the oscilloscope and power supply.

Good news is that current-mode PWM powered LEDs are very closely linear. I managed to find my components in the morning (well, the components found me, actually…)