Category Archives: Professional

SKU142210 big display clock modified with temperature, automatic dimming and semi-automatic software drift compensation

0. Foreword Please, do not post elsewhere the code found here. – The code should reside in one place and people should use links to my site instead. I have a hard time browsing the Internet for pieces of code sometimes, and finding old or obsolete code instead of links to the original developer is […]

EC1204B Led Rotating Clock: Schematic, upgrade, firmware

EC1204B Led Rotating Clock: Schematic, upgrade, firmware 0. Foreword Please, do not post elsewhere the code found here. – the code isn’t ready yet:           – I wish to develop more with several DS1621 sensors on a cable, in order to collect more than one temperature; – The code should reside in one place and […]

Motorcycle (automobile) tail lights with leds and PWM

Motorcycle (automobile) tail lights with leds and PWM   It is trendy to use leds wherever. On automobiles, but especially on motorbikes, where power is of the essence, going down from 10W (or 32W with break lights on) to ~1W is very important. I did this for a friend who owns a Yamaha Venture:   […]

Timer for Ultraviolet exposure with UV LEDs and PWM fine tuning

Timer for Ultraviolet exposure with UV LEDs and PWM fine tuning Timer operation video Timer measurement video Previous timer projects had only on/off possibilities for the UV leds. Some projects need a finer tuning of the UV value, and I am not talking just about PCBs. Stamps and other things need ultraviolet curing, with setups […]

PCB exposure with UV Leds and digital countdown timer DIY

  PCB exposure with UV Leds and digital countdown timer DIY   I have worked for years with a mercury-discharge bulb for exposing PCBs and it started lately to show symptoms of old age. I have decided to retire the old stuff and to replace it with a modern installation, using UV Leds and a […]

State Of The Art Single Layer or Double Layer DIY PCB Production with FR4 or aluminum substrate.

State Of The Art Single Layer or Double Layer DIY PCB Production with FR4 or aluminum substrate   After many years of DIY electronic projects, I can share my experience about having state of the art electronic PCBs, time after time, with zero or at least minimal initial errors. I have chosen a double sided […]

50 MHz Frequency-meter

Frecvențmetru 50 MHz Schema de mai jos este cea a unui frecvențmetru de 50 MHz cu afișaj digital, după o schemă clasică, creat exclusiv cu circuite TTL și CMOS. Frecvențmetrul poate fi utilizat și pentru a măsura direct quarz-uri dar poate fi utilizat și ca sondă logică de nivel TTL prin intermediul afișajului suplimentar de […]

DHCP Rogue Detection and Elimination (EN only)

After having spent several nights searching in a 1500-users network for a rogue dhcp server, coming from a “smart” user who bought a junk router for Christmas, I have decided it’s time to use our knowledge instead of using our nights to solve this issue. How it was done: Two different services work aggregated for […]

Beware Ethernet Flow Control (EN only)

After having been recently bitten by Ethernet’s flow control mechanism, I decided to learn about this somewhat obscure but commonly used facet of modern networks. This post is a summary of what I discovered about it and its associated benefits and dangers. What is flow control? Ethernet flow control, or 802.3x, is a way for […]