Bits & Pieces
Welcome
Projects
Bits & Pieces
Snippets
Reviews
Tools
About
Welcome
Projects
Helmholtz Cage
Introduction
Overview
Coil Drive
Results
Mini Cube Robot
Introduction
Overview
Hardware
Software
Results
Add-on Boards
Motor Test Stand
Introduction
Hardware
Software
Results
Radio Interface
Introduction
Hardware
Software
GUI
Special Features
STM32G4 DAQ
Introduction
Hardware
Software
Results
More...
Bits & Pieces
AFSK
What is AFSK?
Digital Modulation Implementation
Digital Demodulation Implementation
AX5043
The Ultimate Sub-GHz Radio?
RF Frequency Generation
TX Settings
RX Settings
Encoding and Framing
Controlling the Radio
Advanced Features
Experimental Features
Digital Filters
Introduction
FIR Filter
IIR Filter
CIC Filter
ARM CMSIS-DSP Benchmark
Hardware Accelerated Filters (FMAC)
HDLC/AX.25
AX.25 Frame Generator
Overview
AX.25
KISS
HDLC
Encoding
Helmholtz Coil
Basics
Calculator
More...
Snippets
AliExpress Parts
Depth Vision Module
Serial Bus Servo
PX4 Autopilot
Connection to companion computer
Reviews
Antennas
Dual Band Antennas
Korad KD3305P+
Introduction
Observations (Q&A)
Remote Control
Tools
About
MR-Buggy3
Overview of the NXP MR-Buggy3, with upgrades guides for the underlying WL Toys 124019 and some experimental results.
AX5043
A very versatile and configurable Sub-GHz transceiver. Operates from 27 MHz to 1050 MHz. Offers multitude of different modulations like (G)FSK, (G)MSK, AFSK, PSK, ASK and FM, with datarate up to 125 kbps.
HDLC/AX.25
The basics about HDLC, AX.25 and KISS frames, how they are composed and assembled. Interactive online AX.25/HDLC frame generator (encoder and decoder).
LiDAR Modules
Teardown and reverse engineering of a cheap recovered LiDAR acquired from AliExpress. Showing the working principle, how it is implemented and the hardware used as well as how to interface with it by decoding the communication protocol.
Digital Filters
The Basics about Digital Filters like IIR and FIR. How to simulate and design them with SciLab and run them on ARM MCUs using the CMSIS-DSP library as well as on the FMAC of STM32 MCUs. Benchmarks results for different MCUs and settings are also presented.
Helmholtz Coil
The basics about Helmholtz Coils: Basic physics, applications and formulas. Interactive online calculator to aid in designing a simple two coil Helmholtz cage.
AFSK
An explanation on what is AFSK, how it works and for what it is used. Showcase of a digital implementation using Scilab of both modulation and demodulation. This includes FM modulation/demodulation, Audio-FSK modulation/demodulation and emphasis filter.