Sharp Elsimate EL-8118

IMG_2497As you might have noticed, I have a thing about VDF displays and old calculators. This time I found old Sharp EL-8118 which is pocket calculator with basic arithmetic operation with some nice additions. It includes features like settable floating/fixed decimal, sqrt’s and powers, percent and delta percent, constant pi, 1/x or x^(-1) and memory.

It had had battery leak in somewhere its lifetime, but nothing was damaged bad enough and cleaning switch & battery contacts fixed it. It has wear and scratches, but is still sturdy and beautiful calculator. Read More …

VFD Schematics & code witchcraft

I have yet published basic schematics and code for display project. VFD controllerAtmega 16 work as display controller. It will read data from uart serial port, place it to text buffer and simultaneously  multiplex display trough segment voltage buffers and huge digit shift register. ASCII text is converted to segment data and font can be created with computer program. Read More …

Programming xmega with usbasp & avrdude

Few days ago I got package from Helsinki Hacklab. Some generic component stuff and a couple Atmel xmegas and breakout boards for them.IMG_8517 Nice bit more powerful MCU’s than normal atmegas & attinys, but they eat only up to 3.3v, so better not to kill them with 5V logic. Luckily most 5v logics detect 3.3v as high, and their higher output can be lowered with resistor divider. Programing these xmegas also differ from their li’l brothers. Xmegas use  PDI, which is kind of two wire system, constant clock signal and data I/O. I did not have expensive atmel programmer, so I improvised cheap ~2€ programmer using usbasp and avrdude using these patches. Read More …

Debian and stuff

I have had little problem with operating systems. I haven’t found any I could like or use. After Ubuntu 9.10 lost it’s support, and next versions of *buntu distros were all bloated and ugly. Back then I did not have needed knowhow to use other linux or unix systems, so I stuck back to Windows. Anyway I have been experimenting with different OS’s for while now, NetBSD(I can’t get X working), FreeBSD(I can’t get gpu drivers working), Mint(bloated), Xubuntu(still bloated and xfce is terrible) and Haiku(which seems nice but is still heavily incomplete). Only operating system I could get working and bear was Debian Squeeze, because it still have lovely gnome 2, only desktop environment I ever have liked. Read More …

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 …