Bits & Pieces

Overview of the NXP MR-Buggy3, with upgrades guides for the underlying WL Toys 124019 and some experimental results.

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.

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).

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.

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.

The basics about Helmholtz Coils: Basic physics, applications and formulas. Interactive online calculator to aid in designing a simple two coil Helmholtz cage.

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.