Cable crosssections
Just a short summary of the most important data about cable cross sections and current carrying capabilities. Please note that this article is not a substitute of looking up in your local regulations - I just keep these values here to have a quick guess at hand when thinking about such stuff.
Selected OpAmp characteristics
Comparison table / small collection of OpAmps that I'm currently using and their (to me) relevant characteristics
Selected transformer characteristics
Comparison table / small collection of transformers that I'm currently using or are considering to use and their (to me) relevant characteristics
Mil-Style connector overview
A short summary of a subset of the MIL-style connectors that we commonly use. It’s by no way complete or guaranteed to be correct, it’s used as a selection help in case I’m deciding on the proper connector or at least connector category to use for a given application.
dBm power conversion table
A conversion table from dBm to peak to peak voltage, watts and other units for quick lookup
Building a LoRA WAN gateway (and supplying data for the things network)
The following article leads the reader through building an LoRA-WAN gateway from an iMST ic880a concentrator board and an RaspberryPi. Optionally is shows the reader how to add GPS, enable remote configuration via the tinc VPN daemon and via a TOR stealth hidden service.
Using Sonoff basic switches with own firmware
Example how to flash Sonoff basic switches with custom firmware (using cli tools or the Arduino IDE)
Getting started with STM32F401RE Nucleo starter board on FreeBSD
How to get started with the STM32F401RE nucelo development board on FreeBSD with gcc and openocd
Linear stepper motor control - A summary
A short summary of the algorithms required for linear accelerated and decelerated stepper motor control on microcontrolers.
Using AVRs GPIO pins with avr-gcc
How to use the GPIO pins on the AVR microcontrollers when using avr-gcc
I2C communication between RaspberryPi and an AVR based I2C slave
This article explains how to use an AVR as I2C slave device (basically how to set registers for the TWI controller) and how to interface that to an RaspberryPi running FreeBSD
Building an I2C controllable stepper driver board with DRV8825 breakout boards and ATMega328p
This is the description of a small carrier board for two DRV8825 breakout boards (or compatible) that are controlled by an AVR (ATMega328p) which runs a small (linear) motion processor that gets it's commands via I2C.
Using piezo disks for automatic bed leveling on 3D printers
Description of an easy way of using piezo disks as touch sensors to perform bed leveling with 3D printers or other CNC machines. This blog entry describes the most basic possible way without much external circuits (only an ATtiny13A and two resistors are used)
OpenHantek on FreeBSD for USB oscilloscope
A really short description on how to build OpenHantek on FreeBSD and how to configure the system - and how to create a FreeBSD port.
Using Sonoff T4EU1C non-neutral switches with own firmware
A short review about the T4EU1C Sonoff Switch as well as an example how to flash Sonoff basic switches with custom firmware
Capacitance measurement with AVR (simple, fast)
Mini article about the measurement of capacitance with AVRs with a minimum of external components (in it's most extreme form none external components exploiting the gate capacitance of the micro-controllers input)
Z, ABCD, S and T parameters in two port networks
A short summary about the different meaning and interpretation of impedance, ABCD, scattering and transfer parameters in simple (linear) two port networks.
Basic operational amplifier (OpAmp) circuits
Summary of the most basic OpAmp circuits that are usually built as well as their basic properties
RS485 communication using Atmel ATMega328P
Summarizing a method to use RS485 with MAX485 driver ICs on Atmel AVRs (specifically on the ATMega328P) utilizing the on chip USART.
Matching impedance using NanoVNA v2, NanoVNASaver and SimSmith
A mini summary on how to perform impedance matching for antennas or other devices using the NanoVNA v2 together with the NanoVNASaver and SimSmith applications based on the impedance matching of an electron deflection system
Mini note on robust serial communication with microcontrollers
Mini note on robust serial communication with microcontrollers (basically: use checksums and synchronization patterns)
The analog digital converter (ADC) on the ATMega328p and ATMega2560
Mini summary about the ADC on the ATMega328p and ATMega2560
avrdude: verification error, first mismatch at byte 0x0002
A common error - but the solution is easy to forget. And it's even harder when using the Arduino IDE
The AD7705 dual channel analog digital converter with AVRs
Mini summary on how to use the AD7705 with Atmel AVRs
Controlling Pfeiffer Turbopumps using RS485
Pfeiffer makes great turbopumps but sometimes you want to log information or control them from an existing control system. Out of this desire I played around with the RS485 protocol used by Pfeiffer and wrote some simple unofficial tools - that's what this blog entry is about
A simple OpAmp photodiode readout circuit
A short summary on the workings of photodiodes, how one can interface them to simple electronics and a simple amplifier circuit
Building simple function generators using OpAmps (OpAmp based multivibrator)
Summary on how to use operational amplifiers to build simple function generators such as square wave function generators. This approach can be used to build simple laboratory function generators as well as low frequency oscillators used for various applications.
Logarithm and exponential function with OpAmps
A summary how to implement the logarithmic and exponential function using operational amplifiers - and how to use this to build simple mixers when combining with a simple summation amplifier
Controlling the Korad KA3005P using Python
A short summary on how to control the Korad KA3005P power supply using Python as well as some simple samples on how to use my own control library
OpAmp based voltage controllable current source
A simple temperature drift compensated voltage controlled current source up to 8A (10A peak) and 30V rail to rail based on OPA549 or other power operational amplifiers
Simple 230V monitoring using PC817 opto coupler
A really simple circuit to monitor the presence of a 230V AC line using an PC817 opto coupler and a 5V or 3.3V microcontroller
A simple digitally controlled small current source
Simple project that provides a digitally controllable linear current source up to 500 mA powered from a rectified 230V to 12V transformer. The whole current source is bias-able to high voltage (-2 kV in this case) by opto isolating it's serial communication path
Switched mode DC-DC converter basics
A short summary of the basic principles behind switched mode DC-DC converters (buck, boost, buck-boost, etc.), maximum power point tracking and impedance matching as well as a short recapitulation of the charging and discharging of reactive elements such as inductors and capacitors.
Heterodyne, Superheterodyne, Homodyne and Lock-In Amplifier
A mini introduction about the terms heterodyne, superheterodyne, homodyne and lock-in amplifier
Detecting frequency, delay and phase relation as well as multiple targets using correlation functions
A short story about how one can use autocorrelation and cross-correlation functions on discretized samples of radio frequency data and also noise to detect the frequency of a single signal, the delay of a reflected signal, the phase relation between two signals and how one can track multiple reflective targets in applications like LIDAR, sonar or radar using correlations - and how to get them robust against external influence.
Using the FY6900 with an external USB to serial bridge
Short article about circumventing the CH340 contained in the FY6900 function generator by using its external 3.3V serial interface and an CP2102 or any microcontroller.
Using the CP2102N USB to UART bridge
A mini summary (mostly for my own reference) on how to use the CP2102N USB to UART bridge in minimal configurations. This article explains the different powering schemes, lists some of the uncommon functionality and shows the design of a simple USB to TTL serial and USB to RS485 half duplex interface board. In addition it contains a short introduction on how to configure the USB chipsets later on.
Using the RaspberryPi GPIOs on FreeBSD
Mini summary and recipes to use the RaspberryPi GPIOs from FreeBSD
