Archive for November 2020

PIR sensor teardown

This is a tear-down of an interesting PIR (passive infra red) sensor found from some unknown light system believed to be powered from 230V AC. The chips used seem to be ST LM2904 low power opamp and TFK U2100 timer control chip. The sensors are PIR sensor and LDR. The most interesting part is that

tinySA cheap pocket size RF spectrum analyzer

A spectrum analyzer measures the magnitude of an input signal versus frequency within the full frequency range of the instrument. The primary use is to measure the power of the spectrum of known and unknown signals. Spectrum analyzers are widely used to measure the frequency response, noise and distortion characteristics of all kinds of radio-frequency

Short circuit protection

Facebook post at advertises this circuit idea: Amazing Idea With Relay & BC547 Transistor I see this circuit much less than amazing. “This circuit is used as voltage level indicator and short circuit protection circuit.” Voltage level indicator idea is feasible. The “short circuit protection circuit” does not live up to the promises

NanoVNA cable measurements

Having a VNA opens up so many possibilities for RF measurements. Typical measurements are antenna matching, RF filters, impedance matching and cable loss. But it an do more. You can use it even to measure the coaxial cable length – a task that is normally performed with time domain reflectometer (TRD), an instrument I have

Friday Fun: Bar Code

Bar code 1. a method of representing data in a visual, machine-readable form 2. Computer code written or designed at bar under influence of alcohol (possibly during Ballmer Peak moment)

NanoVNA as signal generator

NanoVNA vector signal analyzer can be used also as an RF signal generator. If you are in a hurry and need a quick & square wave signal between 50 kHz and 300 MHz the NanoVNA can come to the rescue. Just set the centre frequency of the stimulus at the value you need and a

Cyber Security News November 2020

This posting is here to collect cyber security news November 2020. I post links to security vulnerability news with short descriptions to comments section of this article. If you are interested in cyber security trends, read my Cyber security trends 2020 posting. You are also free to post related links to comments.