The document describes a project to upgrade an old circuit board from 2012 used in SolAero Technologies' LAPSS capacitance testing process. The upgraded circuit adds a push button to simplify testing and a switch to control the lamp signal. It breaks down the new circuit into sections for debouncing the button, generating a timing pulse, integrating delays, and controlling the lamp and data collection. Schematics, simulations, component selection, and PCB layout were developed for the upgraded circuit board to improve the capacitance testing process.

1. SOLAERO TECH
INTERN
6/25/2015 Eddie Benitez-Jones
SolAero Technologies Corp. is a leading provider of solar cells and
solar panels to satellite and spacecraft OEMs. The business was
founded in 1998 and is one of the world's leading providers of space
solar power solutions. SolAero is headquartered in Albuquerque, NM
and employs approximately 280 people.

2. SolAero Tech Intern
Page 1
Table of Contents
1. Introduction…………………………………………………………………………………….2
2. Background…………………………………………………………………………………….3
3. Solution 2012…………………………………………………………………………………..4
4. Summer Project #1……………………………………………………………………………..6
5. New Circuit Breakdown………………………………………………………………………..7
a) The Push-Button De-bounce………………………………………………………………7
b) 555 Monostable Pulse Generator……………………………………………………….….8
c) Mechanical Switch Bypass…………………………………………………………………8
d) First Time Delay…………………………………………………………………...…….…9
e) Second Time Delay & Trigger Out……………………………………….……...………..10
6. Old & New Circuit Schematics……………………………………………….…..………….12
7. TINA Simulation Results………………………………………………………..……………13
8. Bill of Materials (BOM) ………………………………………………………..…………….14
9. KiCad…………………………………………………………………………….……………17
a) Netlist……………………………………………………………………….…………….17
b) Box Layout………………………………………………………………………………..18
c) PCB Layout………………………………………………………………………………..20
10. Summer Project #1.1 (Project Arduino) ………………………………………...……………21
11. Overview………………………………………………………………………………………22
12. Parts List & New BOM…………………………………………………………………..……23
13. Driving the FET……………………………………………………………………………….25
14. Arduino Box Layout………………………………………………………………………..…26
15. Project Arduino Push-Button Code……………………………………………………………27
16. Excel Training………………………………………………………………………………….29
17. Conclusion……………………………………………………………………………………..30

3. SolAero Tech Intern
Page 2
SolAero Tech Intern
E D D I E B E N I T E Z - J O N E S
Throughout my internship at SolAero Technologies, I was lucky enough to have multiple highly
qualified mentors. For the first half of my internship at SolAero Technologies I was mentored by Gregg
Flynn, the Manager of Production Engineering I. The project I was assigned to was upgrading an old
circuit from 2012 for optimization. SolAero has switched its networks a few times since this circuit was
built in 2012. An uncommented PDF schematics sheet of the old circuit, as well as the PCB hardware
was the only thing I had to work from. My process upon completing this task went as followed:
 Analyze the schematics to figure out what the circuit was doing, and how it functioned
 Simulate the old PCB using TINA
 Gather information on the preferred functionality, as well as some frustrating passed
experiences using the board
 Upgrade the old schematics by changing the circuitry of the board to function as
preferred
 Applying these changes into the TINA simulation
 Research the best components and pieces to build an entire new box using the Digi-key
and front panel designer websites
 Making a BOM of all of the components that are essential for the job
 Designing new components using the library editor and PCB footprint editor to generate
a schematic layout, PCB netlist, PCB layout, and Box layout schematic using KiCad.
Also designing new box using the front panel design website

4. SolAero Tech Intern
Page 3
 Revise the design for optimal efficiency
 Sending Gerber files of PCB layout for a quote on 4 circuit boards
Background
SolAero Technologies has been providing panel circuit capacitance data to customers since at least 2006.
Circuit capacitance has been measured with a procedure that uses the LAPSS to charge up the circuit,
and measures the charging time to determine the circuit capacitance. It appears that either the procedure
has been incorrectly implemented at least since 2006, or that the procedure as documented never
worked. In either case, there is strong evidence that all circuit capacitance values provided by SolAero to
customers since 2006 (or earlier) have been too large by about a factor of 20.
Since a circuit is just an array of cells, circuit capacitance can be computed from cell capacitance using
standard EE methods. The basic measurement method involves charging the circuit capacitance C
(under open-circuit conditions) using the circuit photocurrent Ip while measuring the voltage V across
the circuit.
V(t) = V(t=0) + Q(t)/C = V(t=0) + (1/C)*∫0
t
Ip(t')dt‘
V(t) = (Isc/C)*t (starting with capacitor discharged)
Q is the charge of the capacitor

5. SolAero Tech Intern
Page 4
Ton(10%-90%) usec
Run 1 287
Run 2 292
Average 289
Std. Dev 1.1%
C = Isc*(∆T/∆V) (Capacitance under open-circuit conditions)
The methods SolAero has been using from 2006-2012 yields incorrect (by about a factor of 20)
results because the charging occurs early in the lamp pulse, when the charging current is not
constant and is much less than Isc.
Solution 2012
The method used to solve this problem was to build a LAPSS Capacitance Switch (LCS) that
holds the circuit shorted until the illumination has stabilized at AM0, then remove the short and
record the charging ramp of the circuit. In general, each cell in a circuit charges itself.
Assuming constant AM0 illumination, ramp time will only be a function of cell
capacitance/unitarea, Jsc, and Voc.
623-11 Full Lamp Pulse
-0.06
-0.04
-0.02
0
0.02
0.04
0.06
0.08
0.1
0.12
0 0.001 0.002 0.003 0.004 0.005
Time (s)
Voltage(ProportionaltoLight
Intensity)
623-11
623-11 Lamp Turn On
-0.06
-0.04
-0.02
0
0.02
0.04
0.06
0.08
0.1
0.12
0 0.0002 0.0004 0.0006 0.0008 0.001
Time (s)
Voltage
623-11 Sample 1
623-11 Sample 2
Isc Trace from 623-11 Cell
TON = 290usec
Time for Isc to stabilize is at least
500usec

6. SolAero Tech Intern
Page 5
To fix this problem, we would have to wait until the lamp is all the way on to start charging the
string by using a FET to hold the string in short circuit until lamp is at full power, and then
remove the short circuit and watch the string charge.
LAPSS Capacitance Switch (LCS)
Block Diagram

7. SolAero Tech Intern
Page 6
Summer Project #1
The “New” method implementation of the LAPSS capacitance box needed to be upgraded to meet the
demands of the employees who used the box. These demands were noted as followed:
1. Simplify the box with a push-button to begin testing
2. Add a switch to shut off the signal from the box to the lamp
I began by understanding the functionality of the circuit by analyzing the schematic given to me. The
new circuit will be broken down into sections describing what each part of the circuit is doing.
New Circuit Breakdown
The new LAPSS Capacitance Switch Block Diagram may be seen below. This will be described in detail
by breaking down what each portion of the circuit is doing.

8. SolAero Tech Intern
Page 7
The Push-Button De-bounce
In order to meet customer requirement #1, a pushbutton has been added. The push-button is connected to
a de-bounce. Without de-bouncing, pressing the button once can appear to the circuit as multiple presses.
The de-bounce that was added is simply an S-R flip flop. C1 acts as a decoupling capacitor; you will be
seeing these throughout the circuit attached near each individual IC chip. The de-coupling capacitor is
added for design, and adds a smoothing effect. R15 and R3 are pull-up resistors that make sure the logic
going into the gate is HIGH.

9. SolAero Tech Intern
Page 8
555 Monostable Pulse Generator
The next part of the circuit coming out of the flip flop is a 555 timer. This 555 Mono stable pulse
generator has been integrated into the PCB design, making it no longer necessary to plug in a function
generator in order to generate the 10µs pulse. This pulse will be triggering the lamp to turn on.
Mechanical Switch Bypass
This switch functions as a precaution, and will shut off the capacitance test if both pins 1 and 2 are
LOW. Since the signal going into pin 2 is always LOW, unless triggered by the 555 pulse by pressing
the push button, then the signal from the lamp will continue while the capacitance test is shorted, and
will not go HIGH if the toggle switch is flipped towards the OFF position.
𝑇 = 1.1 ∗ 𝑅1 ∗ 𝐶1
T=1.1(470)(20E-9)
T= 10µs

10. SolAero Tech Intern
Page 9
First Time Delay
The LM339 is an Op-Amp comparator which turns an analog signal into a digital HIGH or LOW,
depending on which pin contains a higher voltage. R5 and R6 are holding the voltage of 2.5v at the
inverting side of the comparator. Since the inverting side of the comparator holds a higher voltage than
the non-inverting side, the digital logic coming out of the op-amp will be LOW. This op amp is also an
integrator, because it has a capacitor in series with the feedback which is going into the non-inverting
pin. The RC time for this circuit may range anywhere from 109µs to 3.409ms, depending on the
resistance setting that the potentiometer is turned to. The minimum amount of time for Isc Trace from
623-11 Cell to stabilize is 500µsec.This delay is used to hold the FET at an open-circuit for the amount
of delay time desired (typically 1ms). This way, the lamp has enough time to charge up to its full
capacity.
T = (R7+P3)*C4
T = 109 µs 3.409ms

11. SolAero Tech Intern
Page 10
Second Time Delay & Trigger Out
TOP: This is simply a voltage follower to force the Op-Amp to adjust the output voltage equal to the
input voltage. This is useful here, since the input impedance of the op amp is very high, giving effective
isolation of the output from the signal source. It also draws very little power from the signal source,
avoiding "loading" effects. The output of the top comparator is attached to a trigger out BNC on the
panel design, which is then connected to O-scope.
Bottom: The bottom comparator acts as another time delay for a set RC time. This time delay cannot be
changed, and lasts for 2.5ms. The delay is almost completely identical to the first delay, excluding the
fact that R12 is not a potentiometer.
𝑉𝑜𝑢𝑡 = 𝑉𝑖𝑛

12. SolAero Tech Intern
Page 11
Second Time Delay & Trigger Out
The last comparator is pulled HIGH, shorting the N-Channel MOSFET, and beginning the capacitance
measurement for the amount specified by the last delay, which is a fixed 2.5ms. Since this FET is an N-
MOSFET, it will turn on (short circuit) when gate to source is anywhere from 2v-4v, and off (open
circuit) whenever the gate to source voltage is smaller than 2v. The 2.5ms delay is more than enough
time needed for the cell to charge, and all measurements to be taken.

13. SolAero Tech Intern
Page 12
OLDSchematics
NewSchematics

14. SolAero Tech Intern
Page 13
TINASimulationResults

15. SolAero Tech Intern
Page 14
Bill of Materials (BOM)
Before I could proceed with the rest of the project, I had to do some research on what kind of
parts I was going to be using in order to get the right PCB surface mount measurements for the
library editor. The next page contains a copy of the BOM that includes information about each
specific part that I would be using for the entire project. By looking up the Digi-Key part
number on the Digi-Key website, I was able to pull up datasheets, shipping information, online
catalogs, extended descriptions, and other important information which could have otherwise
been found by flipping through the product’s datasheet. This BOM includes information about
the parts needed to completely build the box layout, and the PCB. The BOM excludes the price
of wires, zip-ties; mounting screws and the amount to get 4 PCB’s which was quoted to be about
$350.00.

16. SolAero Tech Intern
Page 15
Box
Description Mfr Mfr P/N Dist. Dist. P/N
Q
ty Price
Ext.
Price
RES CHAS MNT 0.1 OHM 1%
50W Ohmite 825FR10E Digikey 850FR10E-ND 1
$
7.43
$
7.43
SWITCH PUSHBUTTON SPDT
6A 125V
TE Connectivity Alcoswitch
Switches MPE106F Digikey 450-1093-ND 1
$
13.86
$
13.86
SWITCH TOGGLE DPST 6A
125V NKK Switches
M2021SS1W01-
BA Digikey 360-3094-ND 1
$
4.66
$
4.66
CAP PUSHBUTTON ROUND
BLACK
TE Connectivity Alcoswitch
Switches 1825068-1 Digikey 450-1490-ND 2
$
0.52
$
1.04
BULKHEAD JACK - SOLDER -
50 OHM Amphenol RF 31-221-RFX Digikey ARFX1064-ND 4
$
2.00
$
8.00
Double Banana Jack with
Binding Post E-Z-Hook 9406 Digikey 461-1217-ND 1
$
6.89
$
6.89
CONN RCPT 5X20
FUSEHOLDER SNAPIN Qualtek 723W-X2/04 Digikey Q206-ND 1
$
1.78
$
1.78
FUSE 250V IEC FA LBC 5X20
2A Littlefuse, Inc 0217002.HXP Digikey F2393-ND
1
0
$
0.31
$
3.12
LINE CORD 3 COND US PHIHONG USA AC30UNA Digikey 993-1039-ND 1
$
3.18
$
3.18
SWITCH ROCKER DPST 20A
125V Illum. Green E-Switch R5BBLKGRNFF1 Digikey EG1534-ND 1
$
2.75
$
2.75
CONVERTER AC/DC 5V OUT
5W CUI Inc FSC-S5-5U Digikey 102-1572-ND 1
$
27.32
$
27.32
CHASSIS 8X16.6X1.75"
BLACK Hammond Manufacturing RM1U1908VBK Digikey HM1004-ND 1
$
108.15
$
108.15
CONN TERM FEMALE 22-
24AWG GOLD
Molex Connector
Corporation 16-02-0087 Digikey WM2512CT-ND
2
5
$
0.21
POLARIZING KEY FOR .100
HOUSINGS
Molex Connector
Corporation 15-04-0292 Digikey WM1033-ND
1
0
$
0.45
$
4.51
CONN HOUS 4POS .100
W/RAMP/RIB Molex Inc 22-01-3047 Digikey WM2002-ND 1
$
0.20
$
0.20
CONN HOUS 6POS .100
W/RAMP/RIB
Molex Connector
Corporation 22-01-3067 Digikey WM2004-ND 2
$
0.58
$
1.16
CONN TERM FEMALE 22-
30AWG TIN
Molex Connector
Corporation 08-50-0114 Digikey WM1114-ND
5
0
$
0.12
CONN HOUSING 2POS .156
W/POLAR
Molex Connector
Corporation 09-50-8023 Digikey WM2111-ND 2
$
0.30
$
0.60
CONN TERM FEMALE 18-
20AWG GOLD
Molex Connector
Corporation 08-58-0189 Digikey WM23942-ND
1
0
$
0.65
$
6.53
TOOL EXTRACTION MOLEX
.100 TERM
Molex Connector
Corporation 11-03-0022 Digikey WM9927-ND 1
$
9.11
$
9.11
STANDOFF HEX 4-40THR
ALUM .375"L Keystone Electronics 2202 Digikey 2202K-ND
2
0
$
0.40
PCB
Description Mfr Mfr P/N Dist. Dist. P/N
Q
ty Price
Ext.
Price
CONN HEADER 5POS .100
R/A TIN
Molex Connector
Corporation 22-05-3051 Digikey WM4303-ND 4
$
1.20
$
4.80
CONN HEADER 4POS .100
R/A TIN
Molex Connector
Corporation 22-05-3041 Digikey WM4302-ND 4
$
0.71
$
2.84
CONN HEADER 2POS .100
R/A TIN Molex Inc 0022053021 Digikey WM4300-ND 4
$
0.32
$
1.28
CONN HEADER 2POS .156
R/A GOLD
Molex Connector
Corporation 26-48-2026 Digikey WM5212-ND 4
$
1.23
$
4.92
MOSFET N-CH 150V TO-247-3 Fairchild Semiconductor FDH055N15A Digikey
FDH055N15A-
ND 4
$
2.45
100uF 10V Aluminum Capacitor Panasonic-ECG
EEE-
HBA101UAP Digikey
PCE4778CT-
ND 4
$
0.66
$
2.64
IC AMP RRIO 4.6MHZ 30V
SOT23-5 National Semiconductor
LM7341MF/NOP
B Digikey
LM7341MFCT-
ND 4
$
2.99
$
11.96
IC COMP QUAD SGL SUPPLY
14SOIC On Semiconductor LM339DR2G Digikey
LM339DR2GO
SCT-ND 4
$
0.47
$
1.88
IC DIODE FAST SW 75V SOD- Fairchild Semiconductor 1N914BWT Digikey 1N914BWTCT- 2 $ $

17. SolAero Tech Intern
Page 16
523F ND 0 0.16 3.20
CAP CER 0.1UF 50V 10% X7R
0603 Kemet
CC0603KRX7R9
BB104 Digikey 311-1344-1-ND
2
0
CAP CER 1000PF 50V 5%
C0G 0603 TDK Corporation
C1608C0G1H102
J080AA Digikey 445-1293-1-ND 4
$
0.11
CAP CER 100PF 50V 5% NP0
0603 TDK Corporation
C1608C0G1H101
J Digikey 445-1281-1-ND
1
2
$
0.01
$
0.15
CAP CER 3300PF 50V 10%
X7R 0603 TDK Corporation
C1608X7R1H332
K Digikey 445-5084-1-ND 8
$
0.01
$
0.11
CAP CER 0.02UF 50V 10%
X7R 0603
Samsung Electro-
Mechanics America, Inc
CL10B203KB8N
NNC Digikey
1276-1984-1-
ND 4
$
0.10
$
0.40
RES 10K OHM 1/10W 1% 0603
SMD Yageo
RC0603FR-
0710KL Digikey
311-
10.0KHRCT-ND
2
0
RES 100K OHM 1/10W 1%
0603 SMD Yageo
RC0603FR-
07100KL Digikey
311-
100KHRCT-ND
2
8
RES 1M OHM 1/10W 1% 0603
SMD Yageo
RC0603FR-
071ML Digikey
311-
1.00MHRCT-
ND 4
RES 33K OHM 1/10W 1% 0603
SMD Yageo
RC0603FR-
0733KL Digikey
311-
33.0KHRCT-ND 8
$
0.01
RES SMD 470 OHM 5% 1/10W
0603 Yageo
RC0603JR-
07470RL Digikey
311-470GRCT-
ND 4
$
0.10
RES SMD 4.7K OHM 5%
1/10W 0603 Yageo
RC0603JR-
074K7L Digikey
311-4.7KGRCT-
ND 4
$
0.10
IC GATE OR 4CH 2-INP 14-
SOIC Texas Instruments CD74HC32M Digikey
296-12804-5-
ND 4
$
0.68
$
2.72
TRIMMER 1M OHM 0.125W
SMD TT Electronics/BI
43WR1MEGLFT
R Digikey 987-1033-1-ND 4
$
3.17
$
12.68
IC OSC SGL TIMER 2.1MHZ 8-
SOIC Texas Instruments TLC555CD Digikey 296-1336-5-ND 4
$
0.88
$
3.52
IC GATE NAND 4CH 2-INP 14-
SOIC Texas Instruments SN74HC00DR Digikey 296-1187-1-ND 4
$
0.56
$
2.24
CAP CER 0.1UF 50V 10% X7R
0603 Kemet
CC0603KRX7R9
BB104 Digikey 311-1344-1-ND
3
2
$
0.10
$
3.20

18. SolAero Tech Intern
Page 17
KiCad
Netlist
After creating a footprint for each component within the circuit, I had to map the components to
their respective footprints by using KiCad. This netlist can be seen below.

19. SolAero Tech Intern
Page 18
Box Layout
By using KiCad’s Eeschema (electronic schematic editor), I was able to build the preferred box
layout. I chose the PCB to be near the panel banana lead connections, because it is necessary to
have the minimum amount of wire going from the panel to the circuit. This way, there is less
wire resistance, and we are able to get more accurate results. The rest of the connections were
not as worrisome, therefore they could be located based on preferred functionality. I placed
frequently used plugs towards the front of the box, and the ones which would be rarely used in
the back.

20. SolAero Tech Intern
Page 19
**A design feature which cannot be seen from this schematic is that all of these wires should be
twisted wire pairs. The reason for this is because noises are generated in signal lines by
magnetic fields from the environment. So the noise current in data lines is the result of that
magnetic field. In the straight cable, all noise current is flowing in the same direction, just like in
an ordinary transformer coil. When the cable is twisted, in some parts of the signal lines the
direction of the noise current is the opposite from the current in other parts of the cable. Because
of this, the resulting noise current is many factors lower than with an ordinary straight cable.
**The black panel designs were not built using KiCad. They were designed using the front panel
website “frontpanelexpress.com/”**

21. SolAero Tech Intern
Page 20
PCB Layout
The PCB layout was built using KiCad, and is a two-layer board with a grounded plane on both
sides. All grounds are connected to the ground plane, rather than wired together. Holes which are not
connected to a wire are also connected to ground. Decoupling capacitors are placed as close as possible
to the power supply for each IC.

22. SolAero Tech Intern
Page 21
Summer Project #1.1
For the second half of my summer internship, management changed and my new supervisor had become
Thomas Dorsey, Sr. Engineer Operations Support. By the time the PCB, the Panel Box and the
components would be shipped in; my contract with SolAero Tech would have ended for the summer.
Due to the limited amount of time that I had left, Thomas proposed that I research alternative methods I
could use for completing this project.
Project Arduino
Project Arduino was one of the alternative methods I had researched on. This project had taken over, and
quickly become my number one priority. Project Arduino is an alternative way to execute similar
waveforms from the previous project.
Since the LAPSS Capacitance circuit generates different waveforms to drive its outputs, I was able to
replicate these waveforms using the Arduino board by programming its microcontroller.
The waveforms I had to mimic were the O’scope Trigger Out, Panel(FET) and Lamp Trigger. These
signals were combined with the button signal and initialized according to their functions.
Initialized to Digital Output pins Initialized to Digital Input pins
1. O’scope Trigger Out
2. Panel (FET)
3. Lamp Trigger
1. Button (receiver)
*It was unnecessary to incorporate delay waveforms, since delays could be added directly in the code.

23. SolAero Tech Intern
Page 22
Overview
The Arduino UNO is a board that is based on the ATmega328 microcontroller. The board has 14 digital
input/output pins (of which 6 can be used as PWM outputs), 6 analog inputs, a 16 MHz ceramic
resonator, a USB connection, a power jack, an ICSP header, and a reset button. There are many
advantages to the Project Arduino method, as opposed to other FPGA boards, or the process shown by
project 1. These advantages are as follows:
 It is an open source and extensible software, this way the plans for the modules are published
under a creative commons license, and circuit designers can make their own version of the
module, therefore extending it and improving it.
 It is very inexpensive compared to other microcontroller platforms. Mimics of the Arduino
UNO R3 can be found for less than $4; free shipping.
 The Arduino software that runs on Windows, Macintosh OSX, and Linux operating systems has
a simple & clear programming environment. This makes it easy-to-use for beginners and
flexible for advanced users to take advantage of the wide variety of Arduino shields for extended
capabilities in their projects.
The disadvantages by using the Arduino over project1 are that the microcontroller requires
programming, and it strips the hardware level access.

24. SolAero Tech Intern
Page 23
New BOM
This new BOM has been updated by replacing the old PCB with the new Arduino materials. This made
the BOM about $450 cheaper, than the old one and saved a lot of time. The list of materials used above
include extra components which were only used for testing to make sure the waveforms were
functioning as expected, however they will not be inside of the box. The only materials which will be
part of the finished design are defined in the BOM below.
The list of the materials from the figures above is:
 1-Infiduino Uno R3 board + 1-USB cable
 MOSFET N-CH 150V TO-247-3
 Wires
 1-Infiduino Extension board + 1-GPIO Extension Board + 1 Connecting Cable
 1-Breadboard
 3-3mm LEDs
 1-Infrared Receiver (or button)
 3-150ohm resistor
 1-Infrared Remote controller
 1-9V Battery slot (with battery)
 Push Button

25. SolAero Tech Intern
Page 24
Box
Description Mfr Mfr P/N Dist. Dist. P/N
Qt
y Price
Ext.
Price
RES CHAS MNT 0.1 OHM 1%
50W Ohmite 825FR10E Digikey 850FR10E-ND 1
$
7.43
$
7.43
SWITCH PUSHBUTTON SPDT
6A 125V
TE Connectivity Alcoswitch
Switches MPE106F Digikey 450-1093-ND 1
$
13.86
$
13.86
SWITCH TOGGLE DPST 6A
125V NKK Switches
M2021SS1W
01-BA Digikey 360-3094-ND 1
$
4.66
$
4.66
CAP PUSHBUTTON ROUND
BLACK
TE Connectivity Alcoswitch
Switches 1825068-1 Digikey 450-1490-ND 2
$
0.52
$
1.04
BULKHEAD JACK - SOLDER -
50 OHM Amphenol RF 31-221-RFX Digikey
ARFX1064-
ND 4
$
2.00
$
8.00
Double Banana Jack with Binding
Post E-Z-Hook 9406 Digikey 461-1217-ND 1
$
6.89
$
6.89
CONN RCPT 5X20
FUSEHOLDER SNAPIN Qualtek 723W-X2/04 Digikey Q206-ND 1
$
1.78
$
1.78
FUSE 250V IEC FA LBC 5X20
2A Littlefuse, Inc 0217002.HXP Digikey F2393-ND 10
$
0.31
$
3.12
LINE CORD 3 COND US PHIHONG USA AC30UNA Digikey 993-1039-ND 1
$
3.18
$
3.18
SWITCH ROCKER DPST 20A
125V Illum. Green E-Switch
R5BBLKGRN
FF1 Digikey EG1534-ND 1
$
2.75
$
2.75
CONVERTER AC/DC 5V OUT
5W CUI Inc FSC-S5-5U Digikey 102-1572-ND 1
$
27.32
$
27.32
CHASSIS 8X16.6X1.75" BLACK Hammond Manufacturing
RM1U1908VB
K Digikey HM1004-ND 1
$
108.15
$
108.15
CONN TERM FEMALE 22-
24AWG GOLD Molex Connector Corporation 16-02-0087 Digikey
WM2512CT-
ND 25
$
0.21
POLARIZING KEY FOR .100
HOUSINGS Molex Connector Corporation 15-04-0292 Digikey WM1033-ND 10
$
0.45
$
4.51
CONN HOUS 4POS .100
W/RAMP/RIB Molex Inc 22-01-3047 Digikey WM2002-ND 1
$
0.20
$
0.20
CONN HOUS 6POS .100
W/RAMP/RIB Molex Connector Corporation 22-01-3067 Digikey WM2004-ND 2
$
0.58
$
1.16
CONN TERM FEMALE 22-
30AWG TIN Molex Connector Corporation 08-50-0114 Digikey WM1114-ND 50
$
0.12
CONN HOUSING 2POS .156
W/POLAR Molex Connector Corporation 09-50-8023 Digikey WM2111-ND 2
$
0.30
$
0.60
CONN TERM FEMALE 18-
20AWG GOLD Molex Connector Corporation 08-58-0189 Digikey WM23942-ND 10
$
0.65
$
6.53
TOOL EXTRACTION MOLEX
.100 TERM Molex Connector Corporation 11-03-0022 Digikey WM9927-ND 1
$
9.11
$
9.11
STANDOFF HEX 4-40THR
ALUM .375"L Keystone Electronics 2202 Digikey 2202K-ND 20
$
0.40
Arduino PCB
Description Mfr Mfr P/N Dist. Dist. P/N
Qt
y Price
Ext.
Price
ARDUINO UNO SMD REV3 Arduino A000073 Digikey 1050-1041-ND 1 $19.00 $19.00
PROTO SHIELD REV3
(ASSEMBLED) Arduino A000077 Digikey 1050-1035-ND 1 $12.00 $12.00
MOSFET N-CH 150V TO-247-3 Fairchild Semiconductor FDH055N15A Digikey
FDH055N15A-
ND 4
$
2.45

26. SolAero Tech Intern
Page 25
Driving the FET
The MOSFET seemed like a complication at first, because it is the only extra component that will be
needed for the Arduino Project. However, after doing some research on the voltage and current limits
that the Arduino UNO, and N-Channel Power Trench MOSFET could take, I came up with the
following.
 When pins on the Arduino are configured to OUTPUT with pinMode(), and set to HIGH by
using digitalWrite(), then the pin is at 5V & ISource ≤ 20mA.
 If the setting is switched to 3V3, then the pin is at 3.3volts & ISource ≤ 10mA.
 Typically, MOSFET’s will switch when the gate voltage reaches anywhere from 2V-5V &
ID = 250μA.
 We are using an N-Channel Power Trench MOSFET which will switch with a voltage of 2V-4V
at the gate. This means that the Arduino’s 3V3 power setting is preferred for driving this FET.
 The FET has been experimented with, and will overheat if placed under the 5V option. When the
FET is under the 3V3 setting, the heat will sink as expected, and no overheating will occur.
**Arduino UNO may be combined with Arduino Extension board to solder components such as
resistors, and the MOSFET. The Panel Design Layout & BOM will not change due to a change of PCB.
Code needs to be added to the program to incorporate the Toggle Switch. **

27. SolAero Tech Intern
Page 26
Arduino Box Layout
As you can see from the new box layout below, not much has changed from project1. The Panel Design
remained untouched, and the box layout simply substitutes the old PCB for Arduino UNO (new one).
The wires will be connected as seen below, and twisted wire pairs will still be preferred for optimal
performance and design. The main uncertainty comes from the toggle switch. As you can see, the toggle
switch is the only unconnected box cut-out, because it is still uncertain whether or not we will want this
design feature. The code for this part has not yet been written, though it could easily be made if desired.

28. SolAero Tech Intern
Page 27
Project Arduino Push-Button Code
I also have code for this project which uses an infrared receiver rather than a push-button. This way the
user may start the test from a distance with an Infrared remote controller, and a code de-bounce is no
longer necessary. The code below has been commented for clarity. If something seems unclear, please let
me know so I can further comment this code.
// Change these values, remember the time is in milliseconds **(##) is the amount of time it should be
const int retest = 2000; //Time untill you can test again(2000)
const int scope = 3; //O'scope time on(3)
const int lamp = .01; //Lamp trigger time on (.01)
/////////////////////////////////////////////////////////////////
// constants won't change. They're used here to set pin numbers:
const int buttonPin = 3; // pushbutton pin IN
const int ledPin0 = 0; // O'scope Trigger OUT
const int ledPin1 = 1; // Lamp Trigger OUT
const int ledPin2 = 2; // Fet Trigger OUT
// Variables will change:
int ledState = LOW; // the current state of the output pin
int buttonState; // the current reading from the input pin
int lastButtonState = LOW; // the previous reading from the input pin
// the following variables are long's because the time, measured in miliseconds,
// will quickly become a bigger number than can be stored in an int.
long lastDebounceTime = 0; // the last time the output pin was toggled
long debounceDelay = 50; // the debounce time; increase if the output flickers
void setup() {
pinMode(buttonPin, INPUT);
pinMode(ledPin0, OUTPUT);
pinMode(ledPin1, OUTPUT);
pinMode(ledPin2, OUTPUT);
// set initial LED state
digitalWrite(ledPin0, ledState);
digitalWrite(ledPin1, LOW);
digitalWrite(ledPin2, HIGH);
}
void loop() {

29. SolAero Tech Intern
Page 28
///////////////////////////////// De-Bounce ////////////////////////////////////
// read the state of the switch into a local variable:
int reading = digitalRead(buttonPin);
// check to see if you just pressed the button
// (i.e. the input went from LOW to HIGH), and you've waited
// long enough since the last press to ignore any noise:
// If the switch changed, due to noise or pressing:
if (reading != lastButtonState) {
// reset the debouncing timer
lastDebounceTime = millis();
}
if ((millis() - lastDebounceTime) > debounceDelay) {
// whatever the reading is at, it's been there for longer
// than the debounce delay, so take it as the actual current state:
// if the button state has changed:
if (reading != buttonState) {
buttonState = reading;
// only toggle the LED if the new button state is HIGH
if (buttonState == HIGH) {
ledState = !ledState;
} } }
//////////////////////// I/O Waveforms ///////////////////////////////
if (reading == HIGH) {
// Lamp Trigger out
digitalWrite(ledPin1,HIGH);
delay(lamp); //Lamp trigger time on (.1)
digitalWrite(ledPin1, LOW);
// O'scope trigger out
digitalWrite(ledPin0, HIGH);
digitalWrite(ledPin2, LOW); //Fet Trigger OUT**
//Panel Trigger Out
delay(scope); //O'scope time on(3)
digitalWrite(ledPin0, LOW);
digitalWrite(ledPin2, HIGH); //**
delay(retest); //2s untill you can test again
}
// save the reading. Next time through the loop,
// it'll be the lastButtonState:
lastButtonState = reading; }

30. SolAero Tech Intern
Page 29
Excel Training
During the summer internship, SolAero provided an on-site Excel training workshop. The workshop was
an intermediate level training session which covered the following topics:
1. Using multiple worksheets and workbooks: This section included linking worksheets with 3-D
formulas, linking workbooks, and managing multiple worksheets and workbooks.
2. Advanced formatting: included using special number formats, using functions to format text,
working with styles, working with themes, and changing the orientation of cells to display text in
special ways; transpose data; and adding background/watermarks.
3. Outlining and subtotals: Included outlining and consolidating data, and creating subtotals.
4. Cell and range names: Included creating and using names, managing names and cell/range
names.
5. Tables: Included sorting and filtering data, advanced filtering and working with tables.
6. Advanced charting: Included chart formatting options, combination charts and graphical
elements.
7. Templates and settings: Included changing application settings, using built in templates and
creating/managing templates.
8. PivotTables and PivotCharts: Included working with PivotTables by rearranging and
formatting them, as well as using PivotCharts.

31. SolAero Tech Intern
Page 30
Conclusion
Since Project Arduino is more efficient in cost, time, and accessibility, it is the suitable method
chosen for this assignment. The circuit is ready to be tested by wiring the I/O ports from the
Arduino, to the LAPSS CAPACITANCE bnc connections as shown on the Arduino Box Layout
portion of this report. If tests come out successful, then an order for the BOM as seen under the
New BOM section shall be ordered, so that the new LAPSS CAPACITANCE measurement box
may be constructed. The results for this project were as followed:
Project 1
All of the requirements have been met, though the order was not shipped and there is no
prototype for this board. If a prototype of this circuit is built then it will have to go through
testing to make sure it works as expected before running experiments using LAPSS.
Project 1.1 (Project Arduino)
The mechanical switch bypass has not been incorporated into the code, since it may seem like an
undesired feature in spite of everything. All other requirements were met, and the circuit works
as it is supposed to. This method is ready to be tested inside LAPSS.
** This internship was a great opportunity to experience the workplace for Electrical
Engineering. I was welcomed and guided through by some incredible mentors, which I owe
many thanks to. The experience was more than I could have expected and allowed me to work on
an engineering project as a professional member of the team. I felt like a major contributor to
SolAero, and hope to see this box working in LAPSS someday. Working for SolAero helped me
use the knowledge I’ve acquired over the past three years as a college student. I also want to
thank the entire staff for taking the time to share their expertise and knowledge of the field. **