Project Two Assembly Guide

Author

Zach Barrett

Published

September 24, 2026


WarningWork in Progress

Overview

This project is about as difficult as Project One, just with more components.

What is refered to as the Top Layer will actually end up facing down when it is fully assembled. The Top Layer has more SMD components than the Bottom Layer, so you should solder that with the Pick-&-Place machine.

Drilling out the slots

As shown with the mechanical drawing on canvas, you will need to drill out some slots in the box you are given.

I recommend covering the outside of your board with masking tape, and drawing the correct locations of your slots in pencil on that masking tape.

To cut the slots themselves, use the drill press to drill holes around the inside edge of the slot, and then use the files to smooth the edges out like so:

THESE ARE DRILL BITS, NOT ENDMILLS.
DO NOT DRILL INTO YOUR BOX AND MOVE IT AROUND.
YOU WILL BREAK THE DRILL BIT.

Acrylic Bending

To bend the acrylic, use the acrylic bending station to heat the bend lines as shown here:

The side flaps should be bent the opposite direction to the top and bottom flaps. When its done, it should look like this from the side:

Components

SMD Components — 35 parts

Designator Comment Description Side Qty Code Bin #
C6 C9 C11 0.1uF SMD capacitor Top 3 - 25
C7 C12 4.7uF SMD capacitor Top 2 - 24
C10 10nF SMD capacitor Top 1 - 9
D9 D10 D11 - Schottky rectifier Top 3 - 27
R14 330R SMD resistor Top 1 331 22
R5 R6 2k2 SMD resistor Top 2 222 19
R7 R10 R20 10k SMD resistor Top 3 103 3
R8 R17 R18 1k SMD resistor Top 3 102 11
R9 820R SMD resistor Top 1 821 17
R11 R12 R13 560R SMD resistor Top 3 561 16
R15 100R SMD resistor Top 1 101 1
R19 8k2 SMD resistor Top 1 822 14
U2 - Decade counter Top 1 - Project Kit
U3 ATTINY2313 8-bit AVR microcontroller Top 1 - Project Kit
U4 555 Timer General-purpose single bipolar timer Top 1 - Project Kit
F1 - PTC resettable fuse Bottom 1 Project Kit
D3 D8 D12 - Schottky rectifier Bottom 3 - 27
D4 D5 D16 - Red LED Bottom 3 - Project Kit
R1 R2 330R SMD resistor Bottom 2 331 22

(This is assuming all resistors are using the 3 digit codes, if they are using 4 digit codes I will update this website.)

Through-Hole Components — 36 parts

Designator Comment Description Side Qty Bin #
BC1 Buck Header, 3 pin, 2.54 mm, straight Top 1 29
C1 4700uF Polarized aluminium capacitor Top 1 Project Kit
C2 C5 C8 100uF Polarized aluminium capacitor Top 3 31
C3 C4 0.1uF Non-polarized ceramic radial capacitor Top 2 21
D1 D2 D6 D7 - Rectifier diode Top 4 26
Q1 Q2 - NPN bipolar transistor Top 2 28
R3 R4 1R Through hole resistor Top 2 15
U1 - 5 V, 2 A LDO, TO-220-3 Top 1 Project Kit
USB1 Battery Charger USB Type-A receptacle Top 1 Project Kit
D13 D14 D15 - 3 mm red LED, through hole Bottom 3 36
LS1 Buzzer Buzzer Bottom 1 Project Kit
P1 Input Selector Header, 2 pin dual row, 2.54 mm Bottom 1 30
P2 ISP Header Box header, 10-way (2x5), 2.54 mm Bottom 1 Project Kit
P3 RST Jumper Header, 2 pin, 2.54 mm Bottom 1 4
P4 A/D Selector Header, 3 pin, 2.54 mm Bottom 1 29
R16 10k Potentiometer Bottom 1 Project Kit
S1 S2 - Button Bottom 2 Project Kit
TM1 TM2 TM3 TM4 Test points Turret mount Bottom 1 32

Misc

Through hole LED direction

This project has a couple of through hole LEDs.

For this project, they go in like this:

SMD diode direction

This project contains multiple SMD schottky diodes. (D3, D8, D9, D10, D11, D12) These are placed on the board like this:

The two lines on the diode can be hard to see, use the microscope!

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