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.

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

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

SolAero Tech Intern

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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)*∫0t Ip(t')dt‘

V(t) = (Isc/C)*t (starting with capacitor discharged)

Q is the charge of the capacitor

SolAero Tech Intern

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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)

Vo

ltag

e (

Pro

po

rtio

nal to

Lig

ht

Inte

nsit

y)

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)

Vo

ltag

e

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

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

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.

SolAero Tech Intern

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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.

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

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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

SolAero Tech Intern

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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

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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.

SolAero Tech Intern

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OL

D S

chem

atic

s

New

Sch

emat

ics

SolAero Tech Intern

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TIN

A S

imu

lati

on

Res

ult

s

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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.

SolAero Tech Intern

Page 15

Box

Description Mfr Mfr P/N Dist. Dist. P/N Qty 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

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 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

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

PCB

Description Mfr Mfr P/N Dist. Dist. P/N Qty 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/NOPB Digikey

LM7341MFCT-ND 4

$ 2.99

$ 11.96

IC COMP QUAD SGL SUPPLY 14SOIC On Semiconductor LM339DR2G Digikey

LM339DR2GOSCT-ND 4

$ 0.47

$ 1.88

IC DIODE FAST SW 75V SOD- Fairchild Semiconductor 1N914BWT Digikey 1N914BWTCT- 2 $ $

SolAero Tech Intern

Page 16

523F ND 0 0.16 3.20

CAP CER 0.1UF 50V 10% X7R 0603 Kemet

CC0603KRX7R9BB104 Digikey 311-1344-1-ND

20

CAP CER 1000PF 50V 5% C0G 0603 TDK Corporation

C1608C0G1H102J080AA Digikey 445-1293-1-ND 4

$ 0.11

CAP CER 100PF 50V 5% NP0 0603 TDK Corporation

C1608C0G1H101J Digikey 445-1281-1-ND

12

$ 0.01

$ 0.15

CAP CER 3300PF 50V 10% X7R 0603 TDK Corporation

C1608X7R1H332K Digikey 445-5084-1-ND 8

$ 0.01

$ 0.11

CAP CER 0.02UF 50V 10% X7R 0603

Samsung Electro-Mechanics America, Inc

CL10B203KB8NNNC 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

20

RES 100K OHM 1/10W 1% 0603 SMD Yageo

RC0603FR-07100KL Digikey

311-100KHRCT-ND

28

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

43WR1MEGLFTR 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

CC0603KRX7R9BB104 Digikey 311-1344-1-ND

32

$ 0.10

$ 3.20

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.

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.

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/”**

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.

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.

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.

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

SolAero Tech Intern

Page 24

Box

Description Mfr Mfr P/N Dist. Dist. P/N Qty 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 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

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 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 Qty 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

$ 210.29

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. **

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.

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() {

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; }

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.

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. **