ECET 105 Week 2 iLab Soldering Techniques and the Electronic Die Kit NEW

Equipment:
Digital Die Kit
Tools:
1 – Soldering Iron
1 – Pair Long-Nose Pliers
1 – Diagonal cutter
1 – Solder and hookup wire
1 – Wire stripper

III.         PROCEDURE
1. Preparation
2. Prepare a well-ventilated and clear workspace with ample lighting.
3. Ensure that the workspace includes a mat to work on in order to prevent the burning of the table or materials during the process.
4. Use a tray, egg crate, or vegetable/fruit tray for all (but especially the small) parts to avoid losing them. Attach the tray with double-sided tape to your bench or desktop.
5. Have a waste basket or desktop trash receptacle handy.
6. Ensure that the sponge that accompanies the soldering iron is sufficiently damp. The level of dampness needed is judged by wetting the sponge and then squeezing out the excess water until the sponge can be held in the hand with no noticeable water dripping from it.

CAUTION:
In order to avoid injury to the eyes, goggles or other eye protection must be worn AT ALL TIMES during the circuit assembly and soldering process.
A soldering iron at temperature is very hot. It is a fire hazard. It is a health hazard. Caution must be taken at all times to ensure that contact with the skin does not occur.
6. Plug in the soldering iron and wait approximately five minutes for the iron to heat to a proper temperature. The temperature of the iron may be tested by lightly rubbing the tip of the iron against the moist sponge. If a majority of water is evaporated, then the iron is ready for use. The tip should be kept clean and tinned for soldering. The sponge is used to wipe away excess solder and materials. Tinning means that there is always a thin layer of solder on the tip.
7. Procure and prepare the dice kit for soldering. Inventory the parts and materials and ensure that each part fits the circuit board correctly by checking the parts on the board WITHOUT soldering them to the board. Put them in the tray until ready to install.
8. Prepare the tools that you will need: soldering iron, rosin core solder, desolder wick, safety glasses, long-nose pliers, and wire cutters.

1.     Assembling the Electronic Die Kit
2. Start with the seven 220 ohm resistors. Note that the color bands are red-red-brown-gold.

2. With your long-nose pliers, bend the legs of all seven of the resistors so that they form 90-degree angles.

3. Insert the 220 ohm resistors into R1, R2, R3, R4, R5, R6, and R7 of your printed circuit board through the side where you see the labels. Bend the lead on the side away from the component part, not next to the resistor body, but on the other side of the pliers. Otherwise, you may break the connection inside the resistor. Ensure that all components, with the exception of the IC socket, are not fully inserted in the board, but have small gaps between them and the circuit board to avoid excessive heating.

4. Prepare to solder the legs of the resistors to the bottom side of the printed circuit board. Turn the board upside down. Caution must be taken to ensure that the “eyelet” solder pads on the board are not stressed with either hands or the tip of the iron during the heating process. The eyelets are easily dislodged and, if damaged, may result in irreparable damage to the circuit board.
In soldering, firmly touch the tip of the iron to the pad AND the lead you want to solder. Ensure that only one wire and one pad (one connection) is heated at a time. When the connection has been heated sufficiently (it should take only a few seconds), touch the solder to the pad, opposite from the tip of the iron, and allow a small amount of solder to flow onto the connection. The parts should not move while you are heating them or they will not form a good joint. Sloppy or careless heating may cause multiple connections to be soldered together, causing damage to the circuit board.
5. Care must be taken as to not apply too much solder because this will result in a convex-shaped connection and, possibly, a cold solder joint. Ideally, the solder should be melted by the connection, not the iron.
6. Remove the iron after ensuring that the solder has spread over the pad and that the lead is sufficiently secured. A resulting concave shape should be observed at the connection. Have your team member or instructor verify proper connection.
7. Trim the excess leads, pointing into a paper or plastic waste bag or basket. Metal clippings may fly far, fall into computer keyboards, or otherwise pose as a shorting hazard.
8. Insert the two, 0.1μF ceramic capacitors into C1 and C2.
9. Solder the legs of the capacitors to the bottom side of the printed circuit board and carefully cut off the excess leads.

1. Insert the 7805, 5-volt regulator into U1 following the drawing on the printed circuit board. Push the component down carefully until it is fully set. DO NOT force the IC all the way onto the board. Push the part partially down and allow the leads to spread out. The result should be that the part stands off the board as shown. Solder and carefully cut excess leads.
2. Insert the 8-pin, IC socket into U2 following the drawing on the printed circuit board. Solder two pins on diagonally opposite corners. (Hold one pin with the heat sink clip or paper clip while soldering the other.) Inspect and confirm that all pins are in the correct holes in the PCB and the socket is seated on the board. Solder each pin and repair any bridging before continuing.
2. Insert the momentary switch into S1 following the drawing on the printed circuit board and solder the two contact pins.
3. Insert the seven red LEDs into D1, D2, D3, D4, D5, D6, and D7 following the drawing on the printed circuit board. PLEASE NOTE that the longer lead of the LEDs is the anode and should go into the hole marked with a + sign.
4. Insert the 9V battery connector into P1 and solder. You may insert the battery leads from the bottom. This will make a neater assembly should you decide to put the Dice in a case. It is VERY IMPORTANT that the red wire is soldered into V+ and the black wire is soldered into V-.

5. Have a team member or your instructor inspect your board when you have finished.
6. Completing and Testing the Kit
7. Inspect the Atmel ATTINY85-20PU microcontroller. Straighten any severely bent pins, very slowly; otherwise, they could break. Align the IC on your breadboard so that the dot in the top lefthand corner of the IC is at the same end as the notch in the IC socket.
Insert the pins on one side, but do not press in, making sure that each pin is started in its socket. Gently press the IC from the other side against the pins started until the pins on the other side easily start in their sockets. Double check that no pin is bent under or is outside of its intended socket location. Press the IC into the socket, firmly but gently.
2. Attach the 9V battery firmly to the battery connector.
3. The die kit should resemble Figure 4.1 when assembly is completed. The Atmel ATTINY85-20PU has been shipped with a program already stored so that the die may be tested by connecting the 9V battery to the connector, then pressing and holding the momentary switch and releasing it. While the switch is pressed, the LEDs will blink in a random pattern. When the switch is released, a randomly generated number between 1 and 6 will be displayed on the LED die. Note any performance issues.