1. Computer Hardware Technology
ELECTROBOT PROJECT

2. 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

3. 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 0’s to add).
Practice this with real resistors!

4. Electricity Theory – Pressure & Flow

5. Basic Measures of Electricity
V- electrical pressure measured in volts (V)
I - current flow measured in amperes (A)
R- resistance measured in ohms (symbol Ω)
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)

6. 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…

7. Resistor Colour Coding
Number
Colour
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…
Tolerance Colours: ±1%brown ±2%red ±5%gold ±10%silver

8. LED – Light Emitting Diode
LED uses V = 2 volts
Works best at I = mA
Must use a resistor R to limit the current or it will burn out.
Calculate R needed if Vsupply = 9 volts (ohm’s law)
R = (V Supply - VLED) / I - +
symbol
– current only flows from + to - lead

9. Parts & Schematic Diagram
9 volts DC
R = 470 ohms
Controller
Mask
Parts:
4 LEDs
470 ohm resistor
Copper tape
5 wires
9 volt battery
Battery terminal
Cardboard

10. 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

11. Soldering
Soldering is the process of joining two metals together using a low temperature melting alloy.
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

12. Soldering Safety 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 ---- > next page

13. 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.

14. 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

15. Soldering Technique Preparation
Use safety glasses and exhaust fan – don’t 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