liacs [HW]
Feb 2017
output / actuators
input – processing - output
electrical control of real world events
• light
– lamp
– led
• movement
–
–
–
–
–
–
electromagnetism
coil, relay (electric switch)
motor
servo motor
speaker
nitinol / memory wire
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
P=V*I
– lamp 1…1000W (1 KW)
power
is
volts
times
amps
– car: 9KW (Citroen 2CV) .. 880KW (Bugatti, 2012)
Output device
vu meter
led
headphone
electromagnet small
small toy motor
servo (light)
PC fan
stepper motor small
servo (heavy)
stepper motor large
cooling fan
automobile headlight
incandescent lamp
electromagnet large
PA speaker 15"
vacuum cleaner
electric heater, stove
Amperes
Volts
100 uA
20 mA
50 mA
100 mA
100 mA
200 mA
100 mA
500 mA
2A
2A
0.2 A
5A
0.25 A
5A
5A
6A
10 A
Arduino output power:
supply from board +5V: max. 300mA .. 1A @ 5V
single output pin: max 40..70mA @ 4V
Watts
1V
2.2 V
3V
5V
5V
5V
12 V
5V
6V
12 V
240 V
12 V
240 V
24 V
40 V
240 V
240 V
100 uW
44 mW
45 mW
500 mW
500 mW
1W
1.2 W
2.5 W
12 W
24 W
48 W
60 W
60 W
120 W
200 W
1440 W
2400 W
ac/dc
dc
dc
ac
dc
dc
dc
dc
dc
dc
dc
ac
dc
ac
dc
ac
ac
ac
Output device
vu meter
led
headphone
electromagnet small
small toy motor
servo (light)
PC fan
stepper motor small
servo (heavy)
stepper motor large
cooling fan
automobile headlight
incandescent lamp
electromagnet large
PA speaker 15"
vacuum cleaner
electric heater, stove
Amperes
Volts
100 uA
20 mA
50 mA
100 mA
100 mA
200 mA
100 mA
500 mA
2A
2A
0.2 A
5A
0.25 A
5A
5A
6A
10 A
Arduino output power:
supply from board +5V: max. 300mA .. 1A @ 5V
single output pin: max 40..70mA @ 4V
Watts
1V
2.2 V
3V
5V
5V
5V
12 V
5V
6V
12 V
240 V
12 V
240 V
24 V
40 V
240 V
240 V
100 uW
44 mW
45 mW
500 mW
500 mW
1W
1.2 W
2.5 W
12 W
24 W
48 W
60 W
60 W
120 W
200 W
1440 W
2400 W
ac/dc
dc
dc
ac
dc
dc
dc
dc
dc
dc
dc
ac
dc
ac
dc
ac
ac
ac
light
LED matrix
led strips / chains – adafruit – sparkfun - ebay
• RGB pixel addressable (neopixel, shift register)
• RGB non-addressable: whole strip the same color
• check common anode(+) / common cathode(-)
• may need constant current driver / buck regulator
• PWM - pulse width modulation
percieved brightness is not linear to duty
cycle
practical approach:
long val = 0..255
analogWrite( (val * val) / 256);
• led PWM controllers
adafruit 12- or 16 bit PWM
– better dynamic range than the 8 bit PWM
from Arduino
– 2 wire interface (SPI)
– high speed refresh w/o using processing
power
– software selectable led current control
– general brightness control
Infrared remote control
TSOP1738 / 1736
infrared receiver
@38(36)KHz
switching 240V AC (mains)
Arduino remoteswitch library / 433MHz Tx module
switching 240V AC (mains)
solid state relay
- zero cross switching
- no sparks
- quiet
- easy interface (LED)
pollin.de 340 470 – 7.95 + transport
electromagnetism
relay
DC Motor Rotation
motor selection
– how fast: RPM (Revolutions Per Minute)
– how strong: geared / ungeared, Watts (V*I)
– bidirectional ?
– AC / DC
– power ( Watts, NM )
how to get one
– video recorder, dvd player, printer, scanner, disk drive
– 240AC household: mixer, fan
– toys
– tools (electric screwdriver, drill)
– RS components
– Pollin surplus, Germany
servo motor
-needs pulses, repeating every 20mS
-pulse length determines position
-arduino library (servo) is available
-may need >> 300mA current (up to 2A) when blocked or loaded
-use extra supply + voltage regulator (7805), common ground
stepper motor
unipolar / bipolar operation – 5 or 4 wires
• motor control
– LN2003/2803 : on/off control
•
•
•
•
•
contains 7 or 8 transistor “darlington” switches
500mA max per switch
up to 30V
includes suppressing diodes
switches to GND only
– L293 : direction and on/off, low power
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•
•
•
dual H-bridge
max 500mA / output
http://www.ti.com/lit/ds/symlink/l293d.pdf
L293D has internal protection diodes
– L298
• dual H-bridge
• http://www.st.com/st-webui/static/active/en/resource/technical/document/datasheet/CD00000240.pdf
• max 40V, total current 4A
– pololu A4988 controller
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•
•
•
supports microstepping
current control, pot adjustable
L/R en Step inputs (only 2 wires + GND)
http://www.pololu.com/product/2128
L298 breakout board
pololu
loudspeaker
sound
laser (mirror)
non-newtonian fluid
arduino synth
• muscle wire - nitinol
good: no moving parts, changes length or shape, silent
bad: takes high current, gets hot, slow release, one way