Few words about me:From very childhood I loved computers, electronics, lasers, sulfuric acid and liquid nitrogen. I always wanted to be making microchips, UAVs and see nuclear explosion.
Now I am doing software engineering and in the spare time - some microelectronics and physics/chemistry experiments.
I live and work in Russia, Moscow.
Radioactivity of natural potassiumAccidentally realized, that natural potassium is radiactive. it has ~0.0117% Potassium-40, which decays with emission of beta-particles & gamma radiation. Radiation levels through are safe even with 1kg of KOH.
I had to remove energy-compensating cover on the Geiger tubes to detect more of beta particles.
Thunderstorm in Moscow
Bitfury - specialized Bitcoin processorRecently we've received sample chips from engineering run of Bitfury - specialized Bitcoin processor.
Compared to Avalon/BFL it is much more advanced thanks to 55nm manufacturing technology (TSMC) and full-custom design. Performance of single chip is ~2-3 Ghash/sec (final numbers are TBD) compared to ~282 Mhash/sec for Avalon.
Designer of Bitfury decided to remain anonymous, it is only known that he is from Ukraine. This was his first ASIC project, he was doing few FPGA projects in the past. What is even more unbelievable is that due to tight time requirements they had to skip MPW run and go straight to full mask run. Cost of mistake was extremely high, but it all worked from the first time. Final devices would be assembled by Metabank in Russia.
PhotosThe package is QFN again (like in Avalon) - due to it's excellent thermal performance and short/low inductance connections to leads.
Read more on zeptobars.ru →
Ring light Sony HVL-RL1I was thinking about buying ring light for my camera for quite some time - and finally accidentally bought it
Sony HVL-RL1 - is a constantly glowing LED light, not a flashlamp. At ISO100-200 one can shoot without tripod with F7.1-F8. I've seen that previous edition of this lamp had 4 times lower light output - and I think it might have been insufficient.
Sample photo with full ring illumination:
Half ring illumination:
Microscope photos of Avalon - specialized Bitcoin processorYifu Guo (designer of Avalon) agreed to send me several chips for decapsulation, but while they were slowly traveling around the world - needbmw gave me damaged chip from his Avalon bitcoin mining unit.
Damaged chip itself (fortunately, die itself is not damaged):
This tiny thing does 282 Mhash/s (like AMD 6970 videocard), consuming ~2.5W of power.
Read more on zeptobars.ru →
Technopolis "Moscow"Visited Technopolis "Moscow". It is like "Skolkovo" for high-volume manufacturing - it offers lower taxes (0% property tax, 15.5% profit tax instead of 20%), simplified customs bureaucracy and huge area (220'000 m2) left after car manufacturing plant ("Moskvich").
This is how it looked before reconstruction:
Moscow city - double rainbow all the way
House mosquito(?) walking on microscope stage
After photo session it was released to the wild - to breath fresh air and eat humans.
BarsFA - 4-transistor full adderFor my transistor-computer project (which is already going for 3 years) I needed compact implementations for most of common digital blocks, and full adder - is one of the most important among these.
Canonical implementation of CMOS full adder takes 28 transistors:
Modern implementations using transmission gate and number of tricks reduce this number down to 8-11, with more strict requirements for transistor selection. These schemes usually could not be used with discrete transistors, as they use 4-terminal transistors, and suffer from degradation of logical 1 level, which becomes even more severe with discrete transistors as they have Vt=1.5-2 compared to ~0.5V for integrated transistors.
The smallest full adder I've seen was using 6 transistors and capacitors at inputs - but I am not sure how to make it work reliable in real-world. Known implementation using bipolar transistors - also using 22 transistors.
But can you make it using only 4 transistors? After thinking and trying few variants, i've got the following schematic working: