Eh! Back me am!

Hopefully, I will be able to keep my promise of blogging more, this time around! Let's see what has happened with me in the last year and half (since my last blog)! In a chronologically random order :P and obviously not complete!

1) I delivered some training kits to CCOEW.
    USB powered, 8051, Parallel ADC/DAC, LCD, 7 segment, Serial ADC/DAC/EEPROM/RTC,
    Keyboard, a test program in assembly that made me feel good about myself.
2) I had to restart programming on lower end PIC micro-controllers (Yuck)
    How can a company manufacture a 8 pin micro-controller that costs @50/- per unit, and NOT give it at
    least one hardware PWM channel, is beyond me!
3) Read Inferno by Dan Brown.
    Another Robert Langdon novel with a storyline similar to Arun Shari's old novel in Marathi (from like
   1975) but with a very unexpected and welcome twist at the end. Loved it. After reading through trash like
   Digital Fortress and Deception Point (Both by Dan Brown) felt good to know that he can still write pretty
   well.

Oh my god! I am boring people with random bits and pieces of my life. That is sick. Yuck.
Next thing you know I will be detailing about what colour shirts I am wearing and asking for opinions!

Maybe people will be more interested in technical stuff that I do sometimes?

I recently  completed testing a spark arc based ozone generator. Uses a Tiny44 controller to drive a small 12V compressor and a HV spark gap drive mechanism (18kV output into a 10mm gap) that generates a continuous spark in a glass tube. The compressor drives air over the spark allowing ozone generation by the UV generated in the spark. Let's see if I can somehow make this into a more commercial product.

Also worked on a LVDT drive circuit recently, that used a completely analog solution, for generating the sine wave (using a Wein bridge oscillator) at 1kHz and synchronous rectification and phase detection that eventually generated 0 to 2V for a 2mm stroke length. The guy who was into manufacturing the circuit had major temperature related issues in the oscillator (sudden shutdowns, frequency drifts, changes in distortion levels and so on so forth).
We tried to temperature stabilize the oscillator gain with a appropriate temperature varying resistive element in the feedback (a tungsten lamp :P). The idea did work, but then there were start-up problems and peak oscillator output related issues.
So I ventured ahead with a simple sine-pwm scheme that used a ATTiny45, running it's output PWM at 100kHz, at 8 bit resolution (Yep, the controller does do that with it's internal PLL etc. etc.) generated a looked up pwm to get a nice low distortion sine wave. And since the person in question has not come back screaming after selling a number of units, I think it is still working. I'll put up all the relevant details soon.

I used LibreOffice Calc to generate the lookup table. Dumped the generated file to a CSV output file. And then generated the output include file (C format, avr-gcc) using a small Python script that used the csv file as input. The Python script was used primarily to arrange the file in a readable form and to make it look nice, put commas and brackets at required places, insert newlines and few comments as seemed appropriate.
Python was an overkill frankly, because the same same task can be done equally well in AWK and in fact even in SeD. But I know both AWK and SeD pretty well, I don't know Python that well and was trying to learn it.

Anyway, now I am working on a KiCAD tutorial as part of the presentation I am to give in my drive to Corrupt Young Minds (with ideas like design your own PCBs instead of paying enormous sums to outsiders, draw neat schematics instead of hand drawn scrawls and similar stuff). I will be posting the tutorial here on the blog as well by end of July first week, sometime.