Archive for October 2011

Bitbang Ethernet

Implementation UDP into microcontroller Igor Atmel-UDP device: UDP/IP infrared remote control web page shows implementation UDP/IP on firmware level (similar as emulation of RS232 interface or USB interface). What makes it really cool is that the ethernet is bitbanged using nothing but the bare pins of an ATMEGA168. The downside is that this Ethernet implementation

CCTV Ground Loop Problems

Humming bars in CCTV system monitor image can be caused by many different factors and tracing the issue can be a pain. Video Ground Loop Interference for CCTV article at 2M CCTV Security & Surveillance Blog gives some tips how to solve ground loop problems on CCTV systems. One cause is running your cable over

UN wants two-thirds of the world online by 2015

Broadband technologies are fundamentally transforming the way we live. UN believes that communication is not just a human need – it is a right. The greater communication and understanding made possible through access to information and communication technologies. In today’s challenging economic climate, recent research has shown that broadband infrastructure and services contribute to economic

Agile hardware development?

Software developers have largely accepted the merits of agile development and commonly debate the value of one agile practice against another. Agile software development is a creative process that does not need all details to be defines in advance. Agile software development is a group of software development methodologies based on iterative and incremental development,

AC current levels

AC current levels 0.25mA  Maximum Leakage Current for Class II equipment in IEC 950 (Information Technology Equipment, I.T.E.) (no protective earth ground in the equipment, double insulation or reinforced insulation) 0.5mA Earth Leakage Current limit in IEC 601-1 (Medical Equipment) (this is general value, here are also other leakage current requirements in IEC 601-1) 0.5mA

Measure with soundcard

Unless you add a measurement instrument to your computer, you have only the sound card as an analog I/O port. You can use the sound card to digitize ac analog voltages but only within a limited range. You can, however, add some signal processing and measure a wider variety of signals, even those that produce

About Things We Build and Fix

When I was last night again fixing old Nokia N73 cellular phone (needed a touch of soldering iron to make volume button to work again) I remember this article I saw few days ago. Are engineers early adopters? article claims that engineers aren’t early adopters of the latest technology. They are more like past the

Counterfeit parts

Watch out for well-made (counterfeit) chips. Counterfeit parts are big headache. Saelae tells that they noticed first that many more boards than normal were failing the functional test. The USB chip was running hot. It turned out that every last part was an old revision corresponding to a different (obsolete) part number – the parts

Mathematics equations in web

How to present math­emat­ical ex­pres­sions using a language that has so little markup for them? Sometimes you can use MathML, but often you need to resort to images. Useful tools and tricks article mentions a nice on-line LaTeX equation writing tool at You type in LaTex or MathML and it creates an image of

FPGA-based Ethernet switches

Ethernet switches are the ubiquitous building block of any intelligent network. Ethernet technology is deployed in virtually every organization’s data center. Wide Area Networking (WAN) and Metropolitan Area Networking (MAN) providers need to provide their customers with Ethernet services. Ethernet has also become the de facto networking technology in industrial automation even in mission-critical local