Low Cost 40Mhz RF Power MeterProject plan

Team DEC13044/30/2013

Low Cost 40Mhz RF Power Meter 2013-4-30

Team Composition

Team Dec1304:

Jason Danielson

Jiwei Xia

Tyler Christensen

Yilun Ji

Client:

PowerFilm, Inc

Dan Stieler

Advisor:

Dr. Ayman Fayed

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Low Cost 40Mhz RF Power Meter 2013-4-30

Table of Contents

Executive Summary 3

Problem Statement 3

General Solution 3

Intended Users and Uses 4

System Block Diagram 4

User Interface Description 5

Functional Requirements 6

Non-Functional Requirements 7

Constraints 7

Technology 7

Risks and Challenges 8

Deliverables 8

Project Management 9

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Low Cost 40Mhz RF Power Meter 2013-4-30

Timeline 9Executive Summary

Powerfilm, Inc. uses RF generators to create plasma enhanced chemical vapor for deposition of thin film solar cells. Since monitoring this area of operation is critical for production costs and end use performance, Powerfilm has asked us to design a cheaper RF Watt meter that will accurately measure a pulsed 40MHz signal at varying frequencies. Alongside a cheaper unit, the addition of a digital display and wireless transmission of the readings to a computer program that will log and report the signals is required.

Problem Statement

Current commercial grade in-line Watt meters exist that will accurately measure pulsed frequencies, but are expensive and do not include a digital readout or wireless transmission.

General Solution

We’ve been advised that it would be to our advantage to break this project into two parts: The first part will be to design the digital readout, logging program, and transmission of data. If we have time we will focus on the second part, the designing a cheaper RF Watt meter. We’ve done this because our group isn’t well versed in RF technology, and believe the currently available Watt meters are most likely the cheapest option right now.

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Low Cost 40Mhz RF Power Meter 2013-4-30

Intended Users and Uses

I. Intended Usersa. Powerfilm, Inc.b. Anyone using these new generators will have the value added

transmission and digital readout.II. Intended Uses

a. Powerfilm uses generated signals to control a plasma. Based on the signals, this plasma deposits material onto the thin film. If the signals are not measured accurately, this can result in an under- or over-coating of material.

System Block Diagram

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Low Cost 40Mhz RF Power Meter 2013-4-30

User Interface Description

I. Digital Readout on Devicea. We will design an LCD screen to readout the data on the

physical unit. This will be visible to the user.II. Designed computer program that logs data in real-time

a. We will write a software and GUI that will show the current readout of the line being tested.

b. A possible GUI will look like this:

As requested, it should have control panel which makes the program connect or disconnect the microcontroller, in this case, MSP430G2553. Also, it requires continuously plotting the data on the screen and is able to adjust how fast the plots update. There should be an option to save the data to a local drive, or upload to a server for future use.

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Low Cost 40Mhz RF Power Meter 2013-4-30

Functional Requirements

I. Accuracya. Stressed by the client, the accuracy of the measurement is

important. The reading can be +/- 10 Watts as long as its always + 10W or – 10W.

b. After confirming again with our client, he thinks consistency is more important than accuracy. In other words, as long as the readings from the meter are consistent with the generated power, the reading will be acceptable.

II. Transmission To Computera. Wireless or USB transmission from unit to computer of real

time measurements.b. Possible wireless transmission method will be either Wifi or

Bluetooth. Wifi is preferred by our advisor, Dr. Fayed, because it has a much stronger signal and wider range. However, according to our client, Bluetooth would work well in our project because the distance between RF generators and the computer is around 10 meters; within the range of Bluetooth.

III. LCD screen attached to the device

The LCD screen is needed to show a digital reading of the output. Because most LCD screens only work at 5V, we need to power it with batteries or another DC source.

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Low Cost 40Mhz RF Power Meter 2013-4-30

IV. Logging and Reporting Software a. This software will log power readings from up to 20 different

devices.

Non-Functional Requirements

I. Software Log Frequencya. User able to determine logging frequency (eg. Every 1 min, 5

min, etc.)b. Display in real time

II. LCD Screen displaya. Will display real time power measurements

Constraints

I. Use of out-of-the-box (OOTB) unit limits measurements to original design of the instrument.

II. N-Type Connectors are needed to match current system setup at Powerfilm.

III. The meter should be able to measure the power between 0 to 1000W

Technologies

a. Microcontrollerb. Texas Instruments MSP430

LaunchpadI. Digital LCD Screen (brand TBD)II. Software Program

a. GUI in C# or Visual Basicb. Callable by in-house uses of Visual Basic

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MSP4302553

Low Cost 40Mhz RF Power Meter 2013-4-30

Risks and Challenges

I. Measured Dataa. Our measured currents and voltages from the unit versus the

power sent are not linear, and different values were attained with our second Bird meter. This could be the result of our “dummy” load we were supplied by Powerfilm, or it could be something else. Having the readings non-linear will make it difficult to achieve an accurate analog to digital conversion.

II. Wireless Technologya. The group has limited knowledge of wireless technology, so

we’re learning as we go. The goal is to have the unit transmit data wirelessly over 802.11 LAN or via Bluetooth and incorporate into our software.

Resources

I. Iowa State labsII. Powerfilm Test lab

a. RF Generatorb. N-type cablesc. A dummy load for testing purposes

III. Advisor/Faculty/Students

Deliverables

Our expected end product will be a modified Bird 43 RF Watt meter. It will have an LCD readout attached, USB port, and a wireless transmitter. A computer program will be included with a GUI that logs and displays measurements in real time for up to 20 devices. An instruction manual and data sheet for our equipment will also be included.

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Low Cost 40Mhz RF Power Meter 2013-4-30

Project Management

I. Jason Danielson – Team Lead focusing on the systems view of the project. Time management, research, steering research and ensuring deliverables completed.

II. Tyler Christensen – Head of Communications focusing on keeping communications open with client, advisor, and group members. Heading the programming of software

III. Yilun Ji – Webmaster and focus on Circuits and microcontroller operation

IV. Jiwei Xia – Focus on microcontroller and Software

Timeline

April/May 2013:

Finish initial programming of microcontroller and ADC in a controlled environment based on measured data obtained at the PowerFilm test lab.

LCD displaying proper values based on a voltage input. Start software design Get our unit communicating to computer via USB End of semester presentation

Summer 2013 Semi-regular group meetings, discussions, and work on the unit

Fall 2013 Final design of software Wireless integration Initial testing on-site at Powerfilm Final design of circuit board manufactured Final testing of device on-site at Powerfilm Instruction manual, datasheet, and other documentation finalized Final product delivered to client

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