School of Engineering Science, Simon Fraser University 8888 University Drive, Burnaby, BC, V5A 1S6

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1 February 14, 2003 Mr. Lakshman One School of Engineering Science Simon Fraser University Burnaby, British Columbia V5A 1S6 RE: ENSC 440 Project Functional Specifications Dear Mr. One Attached you will find the group s Functional Specifications document for the Darkroom Automation System which outlines and explains the full functionality of our project for ENSC 440 this semester. We are in the process of designing and implementing a kit that would digitize an older and failing enlarger device used in large format photography. This kit provides consumers with a user interface from which they could control an enlarger with the push of a button. Please keep in mind that our product can be implemented on almost all such devices since their principles of operation are essentially the same. The purpose of this functional specification is to express the functionality of our entire system by explaining the required functionality of its separate components. Therefore, this report is broken down into two sections, the Base Unit (user interface) Functionality and Head Unit (located inside the enlarger unit) Functionality. Finally the report will bring together how these main units are interconnected. consists of four innovative, experienced and hard working engineering students: Roham Bazarjani, Marijana Cosovic, Hans Johnson and Staphae Lansana, whom are most committed and enthusiastic towards following through with this design project. Please do not hesitate to contact us by at shmr-440@sfu.ca. We look forward to hearing from regarding any comments or questions that you might have. Sincerely, Hans Johnson. Hans Johnson President and CEO Copyright 2003 By

2 Submission Date: February 17, 2003 Version: 1.3 2

3 Executive Summary The current design project being taken on by the team at Photography Inc is called The Dark Room Automation System. It is intended not only to replace the failing electronic components of the Beseler Photographic Enlarger, but to also provide our consumers with a modern, state of the art user interface. The system that is currently in design is considered to be an upgrade kit for the Beseler Photographic Enlarger, but our product can be implemented on almost all such enlarger devices since their principles of operation are essentially the same. This upgrade kit will enable the Beseler 45S to compete with most modern devices available in the market today, the only difference being that our kit will cost much less than one tenth of a new device. This is achieved by replacing light sensors, adding motors to mechanically turn knobs, and by using two microprocessors to analyze user input commands and feedback algorithms. This upgrade kit will consist of two main units, the Head and Base Unit. The user can indirectly communicate with the head unit (placed inside the Beseler enlarger frame) through the user interface unit (a.k.a. the base unit), enabling the user to fully control the enlarger device through a keypad. The Base Unit will perform the following major functions: Process filter settings entered by the user through the keypad. Retrieve previously stored filter settings as requested by the user. Acquire exposure time (timer) from the user. Capable of uploading all previously stored filter settings to host computer via serial port. The Head Unit will perform the following functions: Acquire correct filter values based on the filter settings obtained from the base unit. Determine the current filter positioning based on feedback logic. Direct motors to slide filters until the desired color intensities are reached. Controls the exposure time based on user-inputted timer value obtained from the based unit Updates the LED displays to display current light intensity levels obtained from light sensors. A working prototype of the Dark Room Automation System will be available in April

4 Table of Contents 1. Introduction Intro Scope Intended Audience Acronyms Functional Specification Base Unit Software User Interface Connection Interfaces Hardware Head Unit Electro-Mechanical Control System Power Supplies DC Power Supply AC Power Supply Testing Software Testing Hardware Testing Functionality Testing Limitations Conclusion

5 1. Introduction 1.1. Intro The Darkroom Automation System provides full digital control in the Beseler 45S enlarger and its computerized color heads. This greatly simplifies the work of the photographer when producing prints for dark room photography. This kit also provides the following functionalities: Provides closed loop control of the filter, compensating for the effects of an aging bulb. Maintains a library of filter settings, with one entry for every negative printed. Eases the mundane tasks of creating ring around sheet and test strips. Allows the photographer to manipulate the images in a manner that was not previously possible. This system will consist of two major components: an electronics pack installed within the enlarger head (Head Unit), and a separate, wired remote control unit used for a user interface (Base Unit). Our upgrade kit without the head unit (which is inside the enlarger), along with the Beseler 45S is better illustrated by figure 1 below. 5

6 Figure 1: Dark Room Automation System Overview 1.2. Scope The scope of this document is to outline the functional specifications of our product and the test procedures that we intend to implement on the Darkroom Automation System. Test procedures are in place to ensure that all specifications and functionality are met. Our team is going to be using this document as a guide to develop the prototype Intended Audience This document is intended for the use of design engineers and project management internally. It is also a good basis for developing other documentations such as the design specifications Acronyms DCE : Data Communication Equipment CAN: Controller Area Network 6

7 2. Functional Specification 2.1. Base Unit Head Unit LCD Rabbit 3200 Microcontroller HEX KEYPAD Figure 2: Block Diagram of the Base Unit Software Filter Settings Library Method of Access The user shall be able to recall previous filter settings for a particular negative, based on a serial number associated with that negative. These numbers will be entered using the keypad on the base unit. The user will be able to scroll through all previously stored settings Number of Storage Locations The system will be able to store a minimum of 4000 separate filter settings (onboard the user interface base unit) Non-Volatile The filter settings database shall be preserved even when the system is shut down, and disconnected from the primary electrical supply. This is made possible through a backup battery Settings Stored The database shall contain the filter settings (Cyan, Magenta, and Yellow) for each negative, as well as the date that the negative was first printed. 7

8 Timer Control Resolution The timer function will have a resolution of 0.1s Data Entry The user shall enter the exposure time ATM style. As the numbers are entered, they will scroll to the left, with the last digit being in tenths of a second Filter Control Entry Method The user shall be able to enter filter settings based on the standard Beseler filter values (ranging from 0 to 250). Using the arrow keys, the user can select which of the cyan, magenta, and yellow filter settings they wish to modify Fine Tuning The user shall be able to fine-tune the filter settings while the system is in operation User Interface Liquid Crystal Display Size The liquid crystal display shall be 4 lines by 20 characters. Each character will be 5x7 pixels Lighting The LCD shall have a variable intensity backlight Filter The LCD shall have an optional deep red filter, in order to make the display safe for black and white photography Keypad Type The keypad shall be a hex type keypad, with 4 rows each containing 4 keys. 8

9 Backlighting The keypad shall have a red LED backlight, with the option of making certain keys green Layout The keypad will have the following keys: 0-9, Enter, Cancel, as well as all four directional arrows Footswitch The control system shall have the ability to be controlled via a foot switch. This footswitch shall be useable for starting and stopping exposures Connection Mechanism The footswitch shall connect to the base unit via a standard 1/8 headphone jack Metronome For use in complete darkness, the system shall have a beeper to give the user information regarding the timer Beep Control The user shall be able to select when the beeper will sound. Standard settings will be: once every 10 seconds, every second, every second of the final 10 seconds, and finally, when the timer has expired Backlighting All controls and displays on the base unit will have LED backlighting to increase their usability in the dark Intensity Control The intensity of the backlighting will be variable, under software control. The user will be able to select the intensity level Warning of Low Backup Battery When the voltage of the backup battery drops below a specified voltage, the system shall alert the user that the battery is low, and their database of filter systems is at risk of being lost. 9

10 Connection Interfaces RS232 The system shall be able to connect to a host computer system via an RS232 serial port Connector The serial connector shall be a female DE-9, wired for DCE (eliminating the need for a null modem) Speed and Settings The serial port shall operate at a nominal 9600 baud, using 8N Facilities Available The system shall be able to backup and restore the filter settings database over the serial port CAN 2.04B The base unit shall have a CAN 2.04B interface to be used in communicating with the head unit Connector The CAN Bus connector shall be an RJ-45 connector, permitting the use of a standard Ethernet cable to implement the bus Dallas 1-Wire In order to allow the connection of various sensors (to be added at a future time) the system shall have a Dallas 1-Wire interface Connector The 1-Wire network connection shall be an RJ-11 connector, wired as per the 1-Wire standard Ethernet The Ethernet interface on the Rabbit 3200 shall be exported to the outside of the case. This connection shall be left for future expansion. 10

11 Hardware Power The system shall be powered by an external 9V DC power supply Rabbit 3200 The System shall use a Rabbit 3200 Core Module as it s main processor Housing Durability The housing for the system shall be designed to work in a reasonably harsh environment, although it is expected that it will be used on the dry side of the darkroom Size The system shall be designed to be as compact as possible, based on the size of the primary circuit board, display unit and the keypad. 11

12 2.2. Head Unit 18F458 Micro controller 3-7 Segment LED Display Shutter BASE UNIT Photo Diodes plus filters Light Source Stepper Motor Control Knobs Figure 3: Block Diagram of Head Unit Electro-Mechanical Motor System Motor Type Through the user interface, the user will indirectly control three AP-60 floppy disk motors, which are in charge of the movement of the sliding filters. The motors are also driven by the feedback control system set up on the PIC micro controller with a quadrature coding scheme. 12

13 Motor Speed The motor speed will be determined by the frequency and the phase of its input signals coming from the motor driver and the logic circuit Latching Solenoid (Shutter) Type The latching solenoid allows the shutter to lock in any position (open/close) without the need for a constant supply of power. The shutter enables to leave the light source running without exposing the paper. This solenoid is controlled by the timer, which is set to the exposure time desired by the user Strength Required The latching solenoid must have enough strength to open and close the shutter, which as previous tests have indicated, does not require much driving force Travel Distance The travel distance that the solenoid must push or pull will be dependant on the shutter. The pulse width that is sent to the solenoid controls its travel distance and the physical restraints that we mechanically install will affect this as well Control System Light Sensor Three Colors (Using Filters) These light sensors are essentially photo diodes, whose output signals will be amplified by an opamp, which will convert the current values from the photo diodes into voltage levels which the PIC micro controller will decode as light intensities. By placing three different filters in front each photo diode, we will get intensity readings of three different colors (depending on which filters are chosen) Dynamic Range The light sensors should have the dynamic range to accurately sense all filter values without saturating (from when there are no filters present, to when all three are fully present). 13

14 LED Readouts Information Displayed Under software control the 7 segment LED s located on the Beseler unit will constantly be updated to display the three separate and current filter values Intensity Control The LED controller, MAXIM 7219 and an external circuit will control the intensity of the LEDs. Under software control the user shall have control over the intensity of the displays Controller Board The controller board is a standard micro controller (PIC 18F458) with an on board CAN (Controller Area Network) interface and extended input and output pins Filter Values The controller board compares calculated light intensity values obtained from the color sensors with the user-entered values obtained by communication with the base unit (user interface) Motor Control With the use of feedback control, the head unit will direct the motors (which control the filter values) to move until the desired filter values are reached (user-entered values equals current filter values fed back) Solenoid Control The solenoid is energized by the controller board and is under system software control. It obeys the timer (timing) which is pre-set by the user (through the user interface unit). 14

15 3. Power Supplies 3.1. DC Power Supply The system will have a power supply, which is capable of providing both 5V (internal electronics) and 12V (motors and solenoid) AC Power Supply A stabilized AC power supply shall be constructed to power a 250W halogen projector bulb. It is very important that this supply has a less than 1% variation in its output voltage. 4. Testing 4.1. Software Testing Software testing is going to be performed to insure that the correct interrupts and data are being transmitted. This phase cannot begin, until the hardware has been assembled, since without the hardware components, no serious software can be written Hardware Testing Hardware testing will ensure that all the components meet their specifications and are communicating properly with one another Functionality Testing Functionality testing will ensure that the various functional specifications of the Dark Room Automation system are met. First we shall conduct unit testing to ensure that all the respective units perform as desired. Then we shall test the system as an integral unit in what is known as integration testing. Any of the functional requirements that cannot be implement will then be known Exceptional testing Exceptional testing shall ensure that the system is able to handle non-functional specifications. If the device fails under any circumstance, we shall ensure that it goes into a fail-safe mode. In addition, if the users accidentally request an action from the system that is not covered in the specification, the system will once again go into the fail-safe mode. 15

16 5. Limitations The main limitation of this system as it stands, is that it will not be able to do any automatic color calibrations of the pictures it prints. However, this is partially by design, often automatic color calibration does not work correctly or efficiently, especially for the types of photographs created by professional and semi-professional photographers. 6. Conclusion In this document, we have outlined the various functional requirements of the Dark Room Automation System. We understand that this project has many different components, which are all intertwined. This means that the functionality of each component is essential to the correct operation of the unit as a whole. This is why this report was divided into two parts: the Head and Base Unit functionalities. By first explaining the different components and interconnections of each separate unit, we realized that the functionality of that individual unit became much more clear, and helped us, and hopefully our audience better understand how both major units were associated. With the use of this report as our framework, we can now better manage our priorities, as our group looks forward to the completion of our prototype in April of