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Lab 4 “Bootcamp” (2017)

Laser Fabrication,

Soldering,

Electrical and Mechanical Components

Jump To

Objectives
Lab Part 1 – Mech Construction of Tape Follower
Lab Part 2 – Soldering and Desoldering
Lab Part 3 – QRD and Motors
Lab Part 4 – Inspect connectors and PCBs for the course
Milestones
Additional Videos

Objectives

Complete your tape follower vehicle, in preparation for Lab 5 (PID Control and Tape Following)
Practice your electronics soldering skills
Continue work on laser cut parts/files for your Gesellenstück

Lab Part 1 – Mech Construction of Tape Follower

Continue to build your Tape Follower. You are expected to finish construction as described in the video by the end of the lab.

Links below are from “Labs and Lectures” page.

Tape follower and Gesellenstueck Work Document With Links (BZ)
Tape Follower (basic version) SW model
Tape Follower (fancy, w/arm) SW model
WJ and Laser Tools (5GB .zip file)

Your completed Tape Follower will also have two QRD sensors, two motors, and one TINAH attached to the follower. Instructions for motors and QRDs are listed below.

Once fabrication is completed, start playing with your tape follower: Write some basic code to turn on the motors. See if you can make it run in a straight line. Write code to use the TINAH display to see useful information from your QRD sensors about if, when, and how much they are detecting black tape.

Lab Part 2 – Soldering and Desoldering

1. Plan on approximately 45 min of time to practice these skills. There are 2 irons for every 4 people, so you are expected to share.

2. Review the following videos for soldering

Use eye protection Flux can splash around, and cut wire can can fly everywhere.
Use fume extraction fans Edsyn FXF11 – check you have fan pointing in correct direction
Put water on your solder sponge. (dry sponges are useless)
Watch one useful soldering video (soldering video)
What is Solder? (read useful info about solder, rosin core)

3. Gather materials for soldering practice

You can find most of these materials at the “Wire & Solder” table.

one used PCB (should have old components already soldered in the board)
one piece stranded-core wire (black or red or green or white)
one piece of solid-core wire (blue or orange or yellow or grey)
one 8-pin socket
about 1 foot length of solder.

4. Practice some soldering setup skills

Try each of these skills to ensure you are comfortable handling the equipment.

A. Clean and re-tin your solder tip Your solder iron tips should already be clean and tested, but if solder does not melt onto the tip use Solder Iron Tip Tinner (kept at the front of the lab near the electronics components.). Weller tips have several coatings. Some tips are old and need just a small amount of rubbing with emery cloth to remove oxide layer, but try to avoid doing this.

B. Watch as the rosin boils off the solder. Occasionally bubbles up enough to end up on hands and eyes.

C. Use side cutters to trim long wires on back of PCBs. Notice how far clipped items can fly from the boards, watch out for people around you. Use the 3rd Hand tool to hold the board in place if necessary.

5. Practice soldering a variety of components together

You will show a collection of items to a TA for completion. Here is a suggested list of things to try:

solid-core wires into the PCB
stranded-core wires into the PCB (check for loose strands!)
8-pin sockets into the PCB (solder 1 corner pin first, then ensure the socket is flat on the PCB, then solder the remaining pins)
put two stranded-core wires together to form one longer wire.
coat one stranded-core wire with excess solder. Feel how much stiffer and more brittle the excess solder makes the wire

7. Practice Desoldering

A. Watch videos of desoldering You can use two different methods, the desoldering tool, and solder wick

B. Remove 2 wires from a used PCB (stranded or solid) from a used PCB.

C. Remove one BJTs. See if you can remove it without clipping the leads from the BJT or destroying the component

7. Keep your soldering and desoldering parts for a TA/instructor to inspect as a milestone.

Lab Part 3 – QRD and Motors

1. Watch the video to see the QRD and motors. Tape Follower for ENPH 253

2. Solder the QRD (1 for each person)

A. Required materials

3 pieces of 8″ stranded wire, of 3 different colours

male header pins

one 330 ohm resistor

B. Cut male header pins to correct number of pins. It is plastic, so you can use your side cutters. Be careful, as you may accidentally cut adjacent pins in the header and parts may fly into your face. Return extra pins to bin.

C. Assemble sensor using solder, hot glue, and heat shrink tubing. For the QRD, you will be including an appropriate resistor (330 ohms) inside the QRD wire as shown in the sample and in the diagram here.

Mark the resistor value on the outside with a label.

3. Solder the Motor (1 for each person) (~15 minutes)

NB: Since this step is relatively straghtforward, you may use one of the motors which has been soldered and hot glued for strain relief from last year. Check the bin. Use two pieces of stranded-core wire, approximately 8inches in length.

You can use the screw terminals on the TINAH motor outputs to attach the motor.

Lab Part 4 – Inspect connectors and PCBs for the course

There will be a selection of connectors on tables in the room.

You are encouraged to try using each of the connectors. Try not to waste attempts, as each connector varies in price from reasonable to not reasonable.

- Quick Connect Terminals
- Deans Connectons (for TINAH and battery)
- IDC connectors for ribbon cable
- MTA-100 Connectors (single-wire connections to board)
- Wire Nuts