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liacs [HW] Nov 2018

liacs [HW] Nov 2018. output / actuators. how much power (Watts) is needed. one Watt is the rate at which work is done when an object's  velocity  is held constant at one meter per Second against constant opposing force of one  Newton

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liacs [HW] Nov 2018

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  1. liacs [HW] Nov 2018 output / actuators

  2. how much power (Watts) is needed • one Watt is the rate at which work is done when an object's velocity is held constant at one meter per Second against constant opposing force of one Newton • one Watt is the rate at which work is done when one Ampere (A) of current flows through an electrical potential difference of one Volt (V)determined by both voltage and current: P[W] = U[V] * I[A] • relations between physical quantities: hyper physics • examples • earphone 10..100 milliWatt • LED: 50 mW • resistor: 0.25 W ( V * I < 0.25) • relay: 200…500 mW • power LED 1W • human: 100..200 W • lamp 1…1000W (1 KW) • car: 9KW (Citroen 2CV) .. 880KW (Bugatti, 2012) P = V * I power is volts times amps

  3. Arduino output power: supply from board: +5V: max. 300mA .. 1A -- +3.3V depends on board model single output pin @5V supply: max 40..70mA @ 4V

  4. light

  5. LED matrix

  6. led strips / chains – adafruit – sparkfun - ebay • RGB pixel addressable (neopixel, shift register) • RGB non-addressable: whole strip shows same RGB color • check common anode(+) / common cathode(-) • may need a constant current driver

  7. PWM - pulse width modulation percieved LED brightness is not linear to duty cycle practical approach: longval = 0..255 analogWrite( (val * val) / 256);

  8. PWM – to analog voltage PWM input Voltage output

  9. led PWM controllersadafruit 12- or 16 bit PWM • better dynamic range than the 8 bit PWM from Arduino • 2 wire interface (SPI) • high speed output switching w/o using processor resources • software selectable led current control • general brightness control (all LEDs at once)

  10. Infrared remote control

  11. TSOP1738 / 1736infrared receiver @38(36)KHz

  12. switching 240V AC (mains) • solid state relay • zero cross switching • no sparks • quiet • easy interface (LED) • switches inductive loads like AC motors pollin.de 340470 – 7.95 + transport

  13. electromagnetism

  14. Physical Rythm Macine / Boem BOem

  15. relay = switch activated by electromagnet

  16. pole = # of switches (double, single) throw = switch type (double, single) NO = normally open NC = normally closed relay coil = induction protection diode

  17. toy motor high speed low voltage (3..6V) low current (100-500mA) linear motor linear movement (push-pull) medium voltage (12V) very slow speed

  18. car door opener linear movement fast may need +/- reversal windhield wiper motor slow and very strong 12V / 10-15A geared motor speed depends on gearing power depends on size

  19. DC motor direction control: H-bridge reversing the voltage = reversing direction

  20. motor selection • how fast: RPM (Revolutions Per Minute) • geared / ungeared • bidirectional ? • AC / DC • how strong: output power ( Watts, NM ) • need for speed control ? how to get one • video recorder, dvd player, printer, scanner, disk drive • 240AC household machine: mixer, fan, grill • toys • tools (electric screwdriver, drill) • RS components • Pollin surplus, Germany

  21. servomotor

  22. requires a 0.5..2mS pulse, repeating every 20mS • pulse length determines position • servo library is available for Arduino (controls multiple servos) • may need >> 300mA current (up to 2A) when blocked or loaded, may reset Arduino • uses extra supply + voltage regulator (7805), common ground

  23. stepper motor

  24. unipolar = 5 or 6 wires bipolar = 4 wires

  25. motor control • LN2003/2803 : on/off control • contains 7 or 8 transistor “darlington” switches • 500mA max per switch • up to 30V • includes protection diodes to + supply • switches to GND only • L293 : direction and on/off, low power • dual H-bridge • max 500mA / output • http://www.ti.com/lit/ds/symlink/l293d.pdf • L293D has internal protection diodes • L298 DC motor controller • dual H-bridge • http://www.st.com/st-web-ui/static/active/en/resource/technical/document/datasheet/CD00000240.pdf • max 40V, total current 4A • pololu A4988 stepper motor controller • supports microstepping (HW selectable) • current control, pot adjustable • control: 2 digital signals for L/R and STEP • http://www.pololu.com/product/2128

  26. polulu stepper driver: • current control • micro stepping • u/d and direction signal will do L298 breakout board

  27. loudspeaker sound laser (mirror) non-newtonian fluid arduino synth

  28. muscle wire - nitinol good: no moving parts, changes length or shape, silent bad: requires very high current, gets hot, slow release, one way

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