Circuits by Tomi

Avalanche pulse generator circuit

Pulse generator is an electronic test equipment used to generate rectangular pulses. Pulses are typically injected into a device that is under test and used as a stimulus or clock signal or analyzed as they progress through the device, confirming the proper operation of the device or pinpointing a fault in the device. Typical application

IoT Temperature Meter

This is a test project to build IoT temperature meter using ESP8266 WiFi module, DS18b20 temperature sensor and nodemcu. It sends temperature data to ThingSpeak. This test is based on ESP8266 + ds18b20 + thingspeak+ nodemcu article and it’s files on GitHub plus ds18b20.lua. ESP8266 + ds18b20 + thingspeak+ nodemcu article describes how to build

VMM electronics prototyping method

VMM is a method to implement dense disk built electronic circuit connections without special tools. It is developed by Jouko Paloheimo. VMM enables dense-performance couplings on the building, the method conducted in circuit boards can be used for integrated land use and voltage levels. The method is based on standard circuit board material, thin wiring

AD9850 scalar network analyzer

A network analyzer is an instrument that measures the network parameters of electrical networks. Today, network analyzers commonly measure s–parameters. Full featured network analyzers are expensive instruments, and sometimes a simpler. Scalar Network Analyzer (SNA) is a simpler form of RF network analyzer that only measures the amplitude properties of the device under test.  SNA is

Diode detector for RF

Here is a simple diode detector for RF signals. I can feed RF signal from left and get DC output from right. The DC output can be fed to Arduino analog in. The diode in the circuit is germanium diode for low voltage drop. The circuit works well for fractions of volts to several volts

AD9850 based signal generator

Few days ago I tested AD9850 DDS module in home in hope to some day have a working signal generator using it. The initial tests went well, so I could plan the next step. I was already doing some information searching to make decision if I should do the controlling using web interface (with Ethernet

My PC speaker PWM story

Here is another story from the same era (early 1990′s). It is a continuation to my LPT DAC story. Before PC sound cards became popular, around same time as LPT DAC circuits became popular, PC speaker was also used to play back digital audio. Software (game and other) wanted to have the option to use

My LPT DAC story

Hackaday featured today LPT DAC circuit. Back in the olden days, around 25 years ago, sound cards were rare on PCs. One hack those days was the original Covox Speech Thing, that connected a simple DAC to to PC parallel port. The Covox Speech Thing (also known as Covox plug) was an external audio device

Conductive paint pen challenge

Farnell/Newark/Element14 has been running a Conductive Ink Challenge with deadline of 31st August 2014. In it the competition the plan is to draw artistic circuits by hand using nickel or silver-laced “ink”. The aim is to make eye-catching piece of art.  Judging is based on creativity, originality and technical and is final To test conductive