Unitrex 1200 and lesson

Yesterday I found an old calculator from e-waste center, which caught my attention. At first glance I knew that this was not ordinary VFD or LED display desktop calculator. So I stuffed it into my bag and scurried back to home with my precious find. At home I plugged the calculator into the wall socket, which I probably shouldn’t have done. Of course it did not work. But no worries, what could I could not fix? Read More …

Nixie clock firmware

Firmware for clock is in publishable condition at last. Now all major functions are implemented and no bugs are (yet) found. But there will be likely future versions with slight fixes and features. And yes, it is made with basic, terrible, horrible and not 1337 at all, but  it was easier and I could ask help from friend who have similarly constructed clock. There is also slight chance that I will translate this to avr gcc, but it would be big job, because it have not all functions and stuff. Read More …

Dual buck converter

I had boring day, and was too lazy to do school works, so what else I could do but electronics? For next project I need power supply and due to poor efficiency of linear regulators, I choose to make an another switching regulator.

IMG_7658And there is the blurry picture. Similar construction to the nixie clock’s power supply, but this time double. Read More …

Nixie-clock update

Itty Bitty Buck converter

Everybody knows old 78xx linear regulators. They are ok for many applications, but are problematic for bigger currents. They drop and regulate voltage smoothly for circuitry, but because all excess voltage are dissipate as heat, they are very inefficient. For my nixie clock I needed efficient little power supply for 5V rail, so I created this little baby:

Look how cute it is!

Read More …