Computer Hardware Technology

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Computer Hardware Technology

• ELECTROBOT PROJECT

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Computer Technology ELECTROBOT

• Task Teams of 2 will design and build an
  electronic control system for a 4 LED display
  mask. The controller will then be used to guide a
  team member wearing the mask through a maze. The
  goal is to pick up an object in the least amount
  of time.
• Requirements
• Project report description, diagram and parts
  list
• Safety notes
• Build mask and controller, following tool
  procedures
• Complete a timed race through the maze

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Finding the Value of a Resistor by Color Codes

• Step One Turn the resistor so that the gold or
  silver stripe is at the right end of the
  resistor.
• Step Two Look at the color of the first two
  stripes on the left end. These correspond to the
  first two digits of the resistor value. Use the
  colour table given to determine the first two
  digits.
• Step Three Look at the third stripe from the
  left. This corresponds to the multiplier ( of
  0s to add).
• Practice this with real resistors!

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Electricity Theory Pressure Flow
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Basic Measures of Electricity

• V- electrical pressure measured in volts (V)
• I - current flow measured in amperes (A)
• R- resistance measured in ohms (symbol ?)
• Ohm's Law V I x R
• if you know any 2 values in a circuit you can
  calculate the other value
• Note - Another important measure is Power P
  I x V (in watts)

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Resistors

• Used to control current (I) or voltage (V)
• maximum power level measured in watts (V x I)
  depends on material inside physical size
• resistance value in units of OHMS based on colour
  coded stripes for small resistors
• BBROYGBGW

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Resistor Colour Coding
Number Colour
0 black
1 brown
2 red
3 orange
4 yellow
5 green
6 blue
7 violet
8 grey
9 white

• Colour bands are assigned number values to
  determine the ohm value

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LED Light Emitting Diode

• LED uses V 2 volts
• Works best at I 10- 20mA
• Must use a resistor R to limit the current or it
  will burn out.
• Calculate R needed if Vsupply 9 volts (ohms
  law)
• R (V Supply - VLED) / I

-
symbol

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Parts Schematic Diagram

• Parts
• 4 LEDs
• 470 ohm resistor
• Copper tape
• 5 wires
• 9 volt battery
• Battery terminal
• Cardboard

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Tools Use properly and safely

• Soldering iron
• Safety glasses
• Exhaust fan
• Wire strippers follow the demo
• Wire cutters
• Scissors
• Digital Multimeter (DMM)
• Zero tolerance for misuse or horse play with
  tools and equipment

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Soldering
Soldering is the process of joining two metals
together using a low temperature melting
alloy. http//www.curiousinventor.com/guides/How_T
o_Solder http//store.curiousinventor.com/guides/h
ow_to_solder/heat_solder http//www.sentryair.com
/solder20fume.htm Instructor will assess solder
safety and quality Good solder joints smooth,
shiny, and filled in a concave fashion Poor
solder joints dull, irregular shape and/or
pooled in a blob
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SolderingSafety Hazards

• BURNS Soldering iron tip is very hot (350
  degrees Celsius)
• FUMES Melting metal and flux produces fumes
  that irritate the respiratory and digestive
  system
• SPLASH Hot solder splashes or rosin flux
• POISON Lead is poisonous, and flux can be
  corrosive to skin
• TAKE STRICT PRECAUTIONS ---- gt next page

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Soldering Safety Precautions

• Wear safety glasses
• Keep work areas neat and well spaced
• Hot soldering irons - move slowly
• Keep electrical cords away from iron stand
• Fumes - work in a well ventilated area
• Do not hold parts to be soldered use clips,
  pliers, and other holding tools
• No food in the area
• Hand washing after exposure to solder
• Zero tolerance for misuse or horse play.

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Building the Electrobot

• Prepare five wires of 4 length bundle them
• Strip 1 of insulation off both ends
• Cut out a controller from cardboard (4 x 4)
• Fold and trim 4 switches
• Place copper tape in position
• Secure finished wire bundle with masking tape
• Cut out a LED display of cardboard (3 x 3)
• Mark the and - positions for 4 LEDs
• Make pin holes for LED leads and insert them
• Wrap on 1 wire to each , then 5th wire to 4
  leads
• Begin soldering, following correct procedures
• Safety glasses, fans, holding tools correctly

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Soldering Technique

• Preparation
• Use safety glasses and exhaust fan dont inhale
  any fumes
• Place a wet sponge on the stand clean the tip
  frequently
• Place a mat down to protect the work surface
• Electrical cord runs from front-right or left
  (depending on hand used)
• Parts to be soldered must be clean
• Soldering iron tip should be clean
• Securely position the components to be soldered,
  it should not move
• Application Solder the 4 x 4 control board
  that has been preparedred
• Apply heat at the joint
• Apply solder on the other side of the joint (not
  on the iron)
• Solder will flow once the joint is heated enough
• Do NOT let solder flow for more than 1-2 seconds
• Remove solder wire, and then remove the hot iron
• The solder will harden very quickly