HB100 Doppler Radar, Limpkin’s Amplifier and Arduino MCU – The Details (1/3)

I have a radar module and an amplifier for it, so let’s get cracking …
↓↓↓ Complete description, time index and links below ↓↓↓

But first things first: A short 10 minutes derivation of the Doppler effect and Doppler radar equations – riddled with simplifications and shortcuts to spare you an one hour lecture. But we’ll arrive at the Doppler radar formula nevertheless.

Then we’ll have a detailed look at the HB100 Doppler radar and the signal it delivers. That is followed by a review of Limpkin’s amplifier for it, including performance and schematic. Finally we pair both up and see what they can do.

►Intro
00:00 Intro – HB100 Doppler radars, Limpkin’s amplifiers and an Arduino Nano
►Doppler Effect
00:25 Classical Doppler effect – a simplified derivation with shortcuts
04:21 Doppler effect equations – just for moving observers though
07:53 Doppler radar equations – the ones you’ll find in application notes
►HB100 Doppler Radar
11:08 Working principle – two transistors make an oscillator plus a mixer
13:07 Output signal – millivolt range with DC offset and quite noisy
16:03 Frequency mixer – absolute of the difference between two frequencies
20:51 Calculating velocity – putting numbers into the equations
►Limpkin’s Amplifier
23:09 Overview – they are a simple affair, but there’s a little problem
25:36 Performance – detecting a 1mV sine wave in 50mV noise
28:53 Schematic – 2nd order active bandpass filter and more
34:08 Remarks – application note circuit and Limpkin’s principal of operation
►HB100 With Amplifier
36:14 Idle – picking up the 2nd mains AC harmonic of 100Hz
37:50 Detecting – a moving hand and a moving metal sheet
►Wrap-Up
39:22 Wrap-up – some Arduino code coming up, bye

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#dopplereffect #radar #doppler #microwave #Arduino #tutorials #tutorial #how-to #robertssmorgasbord