Electronics notes/Movement sensing

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This is for beginners and very much by a beginner. It's meant to try to cover hobbyist needs, and as a starting point to find out which may be the relevant details for you, not for definitive information.

Some basics and reference: Volts, amps, energy, power · Ground · batteries · resistors · changing voltage · transistors · fuses · diodes · varistors · capacitors · inductors · transformers · baluns · amplifier notes · frequency generation · skin effect


And some more applied stuff:

IO: IO and wired communication · localish communication · wireless (ISM RF, GSM, RFID, more) · 802.11 (WiFi) · 802.15 (including zigbee)


Sensors: General sensor notes, voltage and current sensing · Knobs and dials · Pressure sensing · Temperature sensing · humidity sensing · Light sensing · Movement sensing · Capacitive sensing · Touch screen notes

Actuators: General actuator notes, circuit protection · Motors and servos · Solenoids

Some stuff I've messed with: Avrusb500v2 · GPS · Hilo GPRS · Bluetooth serial · JY-MCU · DMX · ESC/POS notes

Audio notes: basic audio hacks · microphones · amps and speakers · device voltage and impedance, audio and otherwise ·

Less sorted: Common terms, useful basics, soldering · Microcontroller and computer platforms · Arduino and AVR notes · ESP series notes · Electronics notes/Phase Locked Loop notes · mounts, chip carriers, packages, connectors · signal reflection · pulse modulation · electricity and humans · Unsorted stuff


See also Category:Electronics.


Accelerometer

Measure force in one or more directions.

And, since gravity is a force in a fixed direction, sense direction (as long as not saturated by e.g. being spun very fast)


While small, convenient, and cheap, they are neither the most sensitive or the lowest-noise. As such, they are mostly useful for stronger motion, and most are specced for at least 1g.

Now typically MEMS designs: microelectromechanical - a tiny weight in a chip.


Gyroscope

Measure rotation.


Seismological equipment

Variant naming comes largely from sensitivity (often in units of Volts/(meter/second)).

From geophone (relatively local) to local geologic seismographs to teleseismographs (world-scale) are factors of (very) roughly ten.


Geophone

A geopheone is essentially a physical oscillator tuned to a specific frequency, and a voice coil to sense the movement. (choices on the order of 5Hz, 10Hz, 15Hz, with peak response there and some response a factor ten higher(verify). Lower than 1Hz is not practical.)

You can cheap variants for perhaps USD/EUR20, and more modern ones for perhaps three times that.

Hobbyists can get a decent signal quickly by connecting them direct to a differential ADC. More serious uses would build an in-amp circuit, probably with bandpass.


DIY note: A torn woofer can be made into a geophone by adding a weight on a spring (and solid legs). See e.g. https://zeidigital.wordpress.com/2015/08/14/base-for-earthquake-detector-geophone/

Seismometer

Potentially designed to detect as low as hundredths of a Hz

Unsorted

http://www.infiltec.com/seismo/