Basic Electricity and Electronics for FRC Mike Koch Lead Mentor Muncie Delaware Robotics Team 1720 PhyXTGears
The Quick Tour The Analog World Basic Electricity The Digital World Digital Logic The Rest of the World Microcontrollers
Forces Strong Force Holds nuclei together Electromagnetic Force Magnetism, light, electricity Attractive and repulsive Weak Force Holds electrons in orbit Gravitational Force Masses attract
Chapter I Basic Electricity Voltage Current Resistance
Characteristics by Analogy Potential - Voltage Depth of water behind a dam Flow - Current Water moving through the pipe Limitation Resistance Size of opening
Flavors anyone? DC Direct Current Batteries 1.5 VDC, 3 VDC, 12 VDC AC Alternating Current Commercial electric power 110 VAC, 220 VAC Static Electricity Potential Gradient Lighting
The Characters Voltage (E or V) the difference in potential Current (I) the intensity of the flow Resistance (Ω) the opposition to flow
The Characters Voltage (E or V) measured in Volts Current (I) measured in Amps Resistance (Ω) measured in OHMS
The Characters
Voltage
Current
Resistance
The Carriers/Blockers
The Rules OPEN circuit no current flow
The Rules SHORT circuit = HEAT SMOKE FIRE #1 Rule for SAFETY: KEEP THE SMOKE INSIDE
The Rules OHMS Law Voltage = Current * Resistance
The Rules OHMS Law Current = Voltage / Resistance
The Rules OHMS Law Resistance = Voltage / Current
A Practical Example How much current is flowing in this circuit?
A Practical Example How much current is flowing in this circuit?
A Practical Example How much current is flowing in this circuit? (30 Milliamps or mh)
The Other Rule POWER P = I X E Power = Current x Voltage Watts = Amps x Volts
The Other, Other Rule Capacity Capacity = Current * Time Amp-Hours AH
Batteries Direct Current Rated by Voltage Capacity 12 Volt -17 AmpHours Means: 1 Amp for 17 hours 17 Amps for 1 hour
Battery Tester Computerized Battery Analyzer Available from: West Mountain Radio Model CBA II $110
Battery Tester
The Tools VOM Volt Ohm Meter Multi Meter
Using the Multimeter to Measure Setting up the meter: Units: Ohms Range: High Connections: Ω RESISTANCE NEVER have a power source connected to a resistor when measuring resistance. This could blow the fuse in the meter.
Using the Multimeter to Measure Setting up the meter: Current Range: Higher than expected Units: A, Ma Connections: A or Ma
Using the Multimeter to Measure Voltage Setting up the meter: Range: Higher than expected Units: V Function: DC Connections: V+
Using the Multimeter to Measure Voltage Setting up the meter: Range: Higher than expected Units: V Function: DC Connections: V+
FIRST Electrical Layout - + 120A Circuit Breaker 12V SLA Battery 20A & 30A 40A Circuit Breakers Robot Controller Spike Relay Motor Controllers
Wire Selection and Layout Primary Batteries should last 2-4 matches There is resistance in every wire.001 ohm/ft #10 wire.0004 ohm/ft #6 wire There is resistance at every connection Resistance from wire and connections coupled with high current loads, places a voltage drop along circuit path
Example Drawing 116.4A (stall current of drill motors) over provided battery cables V = I*R V = 116.4A * (.0004 ohm/ft * 8 ft) V = 0.372V This does not include resistances from connections The total drop can be in excess of 0.5V!
Reducing Resistance Check every crimp Use the correct tool Solder critical joints Keep wires short
Analog vs. Digital
Analog vs. Digital Analog Voltage divider Digital Switch 4.5 V 0 or 5.5 V 0 or 5
The Digital World Logic Switches Relays Sensors
Digital Logic Logic Probe Indicates Binary Condition:
Digital Logic Two Conditions: Switch ON OFF Status Voltage High Low 5 V 0 V Boolean TRUE FALSE Binary 1 0
Switches Push Button Rocker Rotary Knife Toggle Micro Wall Decoder
Switches
Switches Light switch (3 way) Toggle switch
Switches Rocker Push-Pull Toggle
Switches Slide Toggle Micro
Switches SPDT
Relay A Switch controlled Electronically
Relay Control Automobile FRC
Relay Provides On or Off In either direction Full 12 VDC
Spike Relay Reverses the Output Voltage or Shorts the Output Used for constant speed motors or high load peripherals
Digital Sensors Produce DISCRETE state changes to indicate ENVIRONMENTAL change Voltage change from 0 to 5 volts Microswitch against a Cam O/P +5 0
Digital Sensors Limit Switch Speed Encoder Position Encoder Quadrature Encoder Optical Isolator
Digital Sensors Limit Switch wiring + 5 V
The Analog World Logic Switches Relays Sensors
Analog Sensors Output an ELECTRICAL change to indicate an ENVIRONMENTAL change Voltage, Current, Resistance or Capacitance IR Proximity sensor changes voltage with distance
Analog Sensors Position Potentiometer Photo Sensor Proximity- Ultrasonic, Infrared
Analog Sensors Voltage changes as Resistance changes
Multiple Output Sensors Camera Analog, I2C, SPI, PWM LiDAR Rangefinder I2C or PWM
Fuses Circuit Breakers Maxi Auto Reset Thermal delay 10 Sec at rating 3.9 Sec at 200%.6 Sec at 400% Thermal fuse
Power Distribution Panel (PDP) 8 x 40 amp fuses 8 x 5-30 amp fuses
Motor Controller Provides Variable Speed Direction For Motors
Logic Gates Buffer Output = Input
Logic Gates NOT (Inverter) Truth Table
AND Logic Gates
NAND Logic Gates
OR Logic Gates
NOR Logic Gates
Logic Gates D Latch Memory storage for 1 bit
The Micro Controller CPU Memory I/O Buses
Basic CPU Central Processing Unit
Memory RAM Random Access Memory ROM Read Only Memory PROM Programmable Read Only Memory EPROM Erasable Programmable Read Only Memory EEPROM Electrically Erasable Programmable Read only Memory
Random Access Memory Temporary Storage of Data Programs Context
Read Only Memory Permanent storage of Programs Data
A MicroProcessor has a few more devices...
I/O Ports External interfaces: Serial Port Parallel Port Digital I/O Analog I/O - Sensors Internal interfaces Hard Disk Video Display
Buses Address Data
CAN Bus Controller Area Network Daisy chain-bi-directional
CAN Bus CAN Bus wires MUST be Green and Yellow
RoboRio Computer
Analog Sensors
Switches Digital Sensors Encoders
Motor Controllers Servos
Spike Relays
Power Distribution Panel (PDP)
Voltage Regulator Module (VRM)
Pneumatic Control Module (PCM)
120 Amp Circuit Breaker On/Off Switch
Free Online Tutorials Basic Electricity http://www.abctlc.com/downloads/courses/basicelectricity.pdf Electronics http://www.play-hookey.com Microcontrollers https://www.newbiehack.com/microcontrollertutorial.aspx Wiring the 2017 FRC Control System http://wpilib.screenstepslive.com/s/4485/m/24166/l/144971-wiring-the-2017-frc-control-system Everything else https://www.allaboutcircuits.com