Traditionally analogue video transmission is done using 75 ohm coaxial cables. Those video signals are not directly compatible with nowadays more widely used twisted pair wiring (CAT5, CAT6 etc..), which means you just can’t wire the signals directly form video output to a twisted pair wire. The mains problems in connecting 75 ohms video source →
I bought some time ago HC-SR04 Ultrasonic Sensor Distance Measuring Module to play with ultrasound distance measurements with Arduino Duemilanove 2009 Atmega 328P SCM Board. The working principle of the HC-SR04 Ultrasonic Sensor Distance Measuring Module when the module get trigger “start” pulse, it sends eight 40khz square wave pulses and automatically detect whether receive →
Twisted pair Ethernet (10 and 100 Mbit/s) uses two pairs of wires. Ethernet (10 Mbit/s works well, 100 Mbit/s sometimes) can be run on the old telephone wiring. There some years ago quite a bit of interest in reusing old telephone wiring for Ethernet connections. Reusing old installed wiring for Ethernet works usually well if →
Inductive amplifier is a type of test instrument that does not require electrical contact to detect an AC wire under voltage. The conventional use of the inductive amplifier is finding the location of hidden wires and breaks in them. Inductive amplifiers can also be used to find an individual cable pair in a telephone cross →
RS-232 serial interface is still quite widely used in many applications. Usually RS-232 Mini Tester with LEDs for indicating state of different signals is all that is needed to make things work. But sometimes seeing signals with your eyes is not enough for troubleshooting and testing. There are nowadays cheap logic analyzers (like Saleae Logic →
The most common joystick type in home computers in 1980′s and some time after that have been Atari-style digital joysticks. Atari 2600 joystick pinout”>Those joysticks are named after Atari, because this joystick type was first introduced in Atari 2600 videogame and then adopted to the home computers introduced on ever since (VIC 20, Commodore 64, →
I bought Fuji HS20 camera few months ago (just some months before the model was discontinued). HS20 is a pretty good superzoom digital camera. It has a very long zoom lens and good macro properties. I have taken many of the photos posted recently to this blog using this camera. To take good macro photographs →
Have you ever wanted to find out how strong a magnet really was, or how the strength of the magnetic field varied as you changed the distance from the magnet. Devices used to measure the local magnetic field are called magnetometers or gaussmeters. There are commercially available meters for this, but they are usually a →
I bought USB Virtual 7.1 Channel External Sound Card Adapter to build a cheap PC based digital storage oscilloscope. Sound card based oscilloscope is not new to me, I have used it sometimes. There are many free oscilloscope software that you can use. For example “zeitnitz” is a very fine program! Using an external USB →
One day I had an old flashlight that had burned light bulb on it. It was a small cheap model powered with two AA batteries. I could fix it with new light bulb, but going through the trouble of trying to find exactly suitable replacement light bulb felt like more than the value of the →