ELECTRICAL



ELECTRICAL

The subsystem decomposition of our design concepts will be presented as follows in the subsequent pages of this documentation:

1) Communication

2) OC Protection

3) Ambient Light Sensor

4) User Interface (Microcontroller vs. Direct SBC)

5) Coordinate Storage

6) Remote kill switch

7) Software

8) Back Plane Power Connection

1) Communication Concept Comparison

Overview

There are several ways in which the user can control the robot. After narrowing down the concepts from the screening stage, we’ve decided that the feasible options are controlling the robot with a tethered remote control, wireless remote control, wireless laptop control via a transceiver, or tethered laptop control via a serial cable.

There are several ways in which the user can control the robot. After narrowing down the concepts from the screening stage, we’ve decided that the feasible options are controlling the robot with a tethered remote control, wireless remote control, wireless laptop control via a transceiver, or tethered laptop control via a serial cable (Shown below in Figure).

[pic]

Figure E1.0

Screening Stage

From this table, we decided to combine concepts D and E due to the face that both concepts will require a tethered PC. Voice control can be eliminated due to cost, difficulty, and overall feasibility. The concepts which will be considered are controlling the robot with a tethered remote, wireless remote, transceiver, and a tethered laptop.

[pic]

Figure E1.1

Selection Stage

From the table it is easy to see that using a PC to control the robot is the best option followed by controlling the robot with a tethered remote. Going wireless would add more complication and cost overall. We decided to weight the cost and difficulty of integration more than the other criteria’s due to our limited budget and time.

[pic]

Figure E1.2

Breakdown of selection criteria

Range - This consists of limitations of range in which the robot can be controlled. Obviously, going with the wireless options will allow for more range. Controlling the robot with a tether will require the user to walk around with the robot.

Cost - This consists of total cost of each option. Assuming a laptop is available; controlling the robot with a tethered laptop is the cheapest option. Off the shelf remote controls, wired or wireless, are relatively similar in price. Having to buy a transceiver would be the most costly option.

Difficulty of Integration - This consists of time required to design and debug each option. All options require some programming to translate signals from the user to the motor controller but the wireless options will definitely be harder to integrate due to interference. The tethered PC control would be the easiest option due to the fact it contains the least amount of variables needed to be designed and debugged.

Safety - This includes how safe each option is. Clearly, the wireless options are safer. Walking around with a tether is slightly more dangerous due to the fact that someone could potentially trip over the tether.

Scalability - This refers to how scalable each option is. This isn’t a real concern for out team but when it comes to controlling a robot which can carry 100kg or 100kg, the wireless options would be more feasible.

Ease of Use - This refers to how easy the user will be able to control the robot. All 4 options should ideally be easy to use. The only difference between using wired/wireless remote and using a PC (transceiver or tethered) would be the limited functionality of the remotes. Using a laptop to control the robot would allow for more functions to be programmed.

Durability - This refers to how durable each option would be physically and electronically. Physically a remote (wired or wireless) would be more durable than a PC. Electronically, the wireless options are subject to more interference than a tethered control.

Cool Factor - This refers to how impressive the overall system will be to the user. Clearly, wireless control would have a higher cool factor than a tethered robot.

Accuracy - This refers to how accurate the user can control the robot. Controlling the robot via a wireless connection is subject to more interference which would lead to less accuracy.

Portability - This refers to how portable each option is. Using the remotes would clearly be more portable than carrying around a laptop.

Ease of Manufacture - This includes all prototyping and construction of a final system. This also includes the programmable ease and overall design difficulty. Programmable ease refers to the ease with which someone can implement the needed functionality with respect to the programming needs.

Possible Options and Pricings

Transceiver Option:

Parallax 433 MHz RF Transceiver Package

Price:  $109.95

. [pic]

Figure E1.3

DESCRIPTION: 

The Parallax RF modules provide a very easy and low-cost method of sending data between microcontrollers from 500 ft+ line-of-sight. This transceiver package comes with two receivers and two transmitters, everything you need for bi-directional communication!

This device can be connected to a PC serial port using a MAX232 line driver. The circuit isn't supported by Parallax, but it's possible to make this connection with a few dollars of parts.

SPECIFICATIONS:

|PCB Size: |0.9"x1.9" (without antenna) |

|Overall Size: |0.9"x3.6" (with antenna) |

|Power: |5V +/-10% |

|Current: |~10 mA normal operation |

| |~3 mA during power down. |

|Data Rate: |12,000 - 19.2 K baud (controller dependent) |

|Frequency: |433.92 Mhz (UHF) |

|Transmission |500 ft+, based on environment conditions. |

|Weight |.4 lb |

Figure E1.4

REFERENCE:



Possible Remotes:

• 4-TH 4-Channel FM Radio

Price: $89.99

[pic]

Figure E1.5

SPECIFICATIONS:

Transmitter: 4-channel

Operating Frequency: 72MHz

Modulation Type: FM narrow band Output Power: less than 0.75W

Receiver: 7-channel

Current Drain: 180mA  Features

4-channel narrow-band transmitter

7-channel, dual conversion, narrow-band 72MHz FM receiver

9.6V 600mAh transmitter NiCd

4.8V 600mAh receiver NiCd

110V AC NiCd wall charger

REFERENCE:



• FUTABA 2 ER 2 Channel System

Price: $44.99

[pic]

Figure E1.6

Ideal for eager new car, boat and plane fans, and the 2ER’s stylish case features front-mounted fine trims for easier access and shorter sticks that allow modelers with smaller hands a full range of motion. Servo reversing, fine trims also included. In addition, the 2ER is available with two S3003 precision standard servos for all-around car, boat and aircraft use. The 2ER requires 12 “AA” cells (8 w/BEC use). Available on 27,72 & 75MHz. 1-year warranty.

2ER SYSTEM SPECIFICS:

Bioengineered transmitter includes contoured sides and a flattened strip on the backplate to increase grip strength

• Sticks are just 3/4” high, allowing small-handed modelers a full range of movement

• All controls and lights are placed within a 5” wide by 2” high area for easy viewing

• Battery Door on front panel speeds battery change

REFERENCE:



Pro’s and Cons

[pic]

Figure E1.7

Conclusion

We’ve narrowed the choices down to either using a tethered remote or a laptop with a tether. This is partially due to the fact that there will be a wireless design team in the future. We will try our best to make it as easy as possible to be able to transition to wireless in the future if desired. We’ve also decided to go with the tethered route because it would be easier to design and implement overall and it would be cheaper than its wireless counterparts. Ideally we would like to get a tethered remote onto the robot but regardless of that fact, we will have the tethered PC to control the robot.

2) OC Protection Method:

Overview

Safe operation of the robotic platform, as outlined in the project readiness packet, is of paramount concern to the customer. From an electrical standpoint, a system is considered safe at the topmost level when it has a built-in method to deal with electrical faults. In this case, an electrical fault can be described as an electrical failure which causes a sudden and dangerous amount of current draw. This condition is known as an over current (OC) fault, and if left unchecked can cause extreme heating leading to fire and possible electric shock. Several methods are available to monitor the current draw from the main batteries, and in the case of an OC fault, shut the system down. These methods are presented in Pugh Chart form in Table 1.1.

Screening Stage

[pic]

Figure E2.0

Following Pugh Chart guidelines, a reference design was chosen to which all other designs were rated. A basic Fuse was chosen as the reference design because they are readily available, simple to implement, and meet the minimum requirements for safety.

Selection Stage

Using the results from the initial screening process, the Fuse protection method was eliminated. It was decided that the Circuit Breaker, Hot Plug Controller, and Micro Controller methods all offered at least the same amount of protection as the Fuse, but had additional features which made them more attractive.

Using these results, another Pugh Chart was created, as shown in Table 1.2.

[pic]

Figure E2.1

In the second Pugh Chart, each selection criteria was given a weight and each method a weighted score. From table 1.2, it was decided that the Circuit Breaker and Hot Plug Controller method were concepts worth developing into prototype form.

Break Down of Selection Criteria

Ease of Use - This consists of how easy it is for the end user to identify and deal with an OC Fault condition.

Labor/Material Cost - These subcategories deal with the cost of developing each method in terms of raw material cost and engineering time.

Ease of Manufacture - This subcategory deals with how difficult the finished product will be to build. Material cost, construction time, and construction complexity are all considered.

Scalable - This subcategory takes into account how scalable (both up and down) each design method is. To be considered scalable, a design method must be able to be scaled up or down with a minimal (preferably no) design changes.

Safety - This subcategory deals with how the resulting design meets the over current protection requirement, as well as any other safety features the resulting design adds to the platform.

Durability/ Accuracy - This subcategory deals with how durable/ accurate the resulting design will be. A design is considered accurate if it stops an OC fault at its defined current level. Durability can play a role in how accurate the resulting design is.

Cool Factor - This subcategory deals with how much of a cool factor is added to the robot by implementing the chosen design.

Concept 1 - Circuit Breaker

[pic]

Figure E2.2

PROS

• Implementation cost – breaker can be bought pre-made.

• Complexity – stand alone mechanical device with few moving parts.

• Multi-use – breaker can be reset after fault.

• Cost – low cost in terms of both material and labor.

CONS

• Not customizable – trip point is not customizable.

• Not fully automated - breaker must be manually reset after a fault.

• False trips – breaker may be tripped when motor(s) first start.

• Accuracy

Concept 2 – Hot Plug Controller

[pic]

Figure E2.3

PROS

• Fully customizable – trip point can be set through the use of a resistor.

• Fully automated – no need to reset after a fault.

• Multi use – controller will reset itself after fault.

• PGood indicator – LED indicator can be setup to signal proper operation.

• Kill switch – Enable pin can be used as a kill switch.

• High Reliability - controller has two levels of protection which limits false trips.

CONS

• Complexity – controller will require a PCB and proper layout.

• Labor intensive – PCB board, bench testing, component selection.

Proposed Controllers

• Intersil Hot Plug Controller (ISL6115):

[pic]

Figure E2.4

• Maxim Hot Plug Controller (MAX5924):

[pic]

Figure E2.5

• Linear Technology Hot Plug Controller (LTC1422):

[pic]

Figure E2.6

Estimated BOM based on Intersil circuit:

[pic]

Figure E2.7

Conclusion

Using the results of the Pugh Chart, the Pros/Cons, and the block diagram, it was determined that the Hot Plug Controller method would best meet the safety needs of the project readiness packet and therefore was chosen as the over current protection method.

3) Ambient Light Sensor

Overview

One of the main design requirements in the project readiness packet was the need for the robotic platform to exhibit a “cool” factor. While the project readiness packet does not explicitly state what is meant by cool factor, from direct conversations with the customer, the platform must appeal to high school students while at the same time showcasing RIT’s engineering abilities. To help meet this goal, it was proposed that an ambient light senor be added to the platform. This sensor would then control LEDs placed on the platform, causing the robot to glow in low light levels. Table 1.1 examines the cost vs. benefits of implementing such a solution.

Selection Stage

[pic]

Figure E3.0

Concept 1 – Ambient Light Sensor

[pic]

Figure E3.1

PROS

• Cool factor – LEDs on platform will light automatically, depending on ambient light conditions.

CONS

• Added Complexity – will need small PCB layout. Current light sensor requires 5Vin (can be provided with simple LDO).

Proposed Light Sensor

[pic]

Figure E3.2

Estimated BOM

[pic]

Figure E3.3

:

Conclusion

From the Pugh Chart and Pro/Cons comparison, it was decided that the addition of an ambient light sensor would be worth the cost and engineering time needed to implement it.

4) User Interface (Microcontroller vs. Direct SBC)

Overview

The reception of user input from the world into the system can be done in two ways as identified above. The principle difference is the method used to decode the user inputs and translate them into signals that can be interpreted and stored by the system. The system in this case can be though of as the single board computer provided by the motor control team. This piece of hardware has the highest level of performance in providing general computing functionality to the robot and so it is used as the central control system for the platform. All navigational and control algorithms will be handled to some extent by the single board computer. What follows is the determination of what level of integration the SBC will have in the interfacing to the external world (user).

[pic]

Figure E4.0

Selection Stage

[pic]

Figure E4.1

From the table, it is easy to add a microprocessor to the system to interpret external data would add complication to the data stream. Therefore, we have decided to integrate the needs into the SBC. This will eliminate most hardware prototyping for the interface and as a result, almost the entire interface scheme can be software defined which has the added benefits of scalability and supportability. This comes with the cost of increased software development and may eventually limit the communications scheme.

Break Down of Selection Criteria

Hardware Connections - This consists of all electrical connections that would be needed in order to support this concept. This microcontroller not only needs supporting hardware such a RS-232 level translator and power conditioning but also needs a way to interface itself to the PC104 bus. If there were many more inputs from the world (not including sensors) it may be worth it to use a microcontroller to interface to the system but with only two inputs, simple hardware can be used in conjunction with software daemons running on the SBC (Linux kernel) to achieve the needed functionality.

Development Needed - This includes all prototyping and construction of a final system. Again, the microcontroller solution requires vastly more resources here. The micro would add another level of difficulty in the software realm as well as the hardware requirements. It would be easy to get bogged down here with the microcontroller solution.

Programmable Ease - This refers to the ease with which someone can implement the needed functionality with respect to the programming needs. The micro adds another entire development environment for the developer to become acquainted with as well as the need of learning the architecture of the microcontroller which can be daunting compared to developing in a Linux environment.

Overall Design Difficulty - This is a sort of catch-all for all other design concerns. It includes things like hardware procurement, cost and system reliability. Again, since the micro solution requires more parts, it is the loser here. Ordering parts is more difficult than developing with hardware already on campus (the motor control team has a SBC). Also, since the micro solution has more parts, the system will be less reliable as well as more difficult to assemble.

Expandability Ease - This refers to how easy it will be to integrate different user input schemes. The microcontroller has an advantage here since it could feasibly devote 100% to the task of receiving user input while the SBC will always have other things to do. Also, non digital communication methods will probably need hardware interfacing to the PC104 bus.

Concept 1 - Microcontroller interface

PROS

• Lowers workload of the SBC

• May be easier to connect peripherals to the system with a translation scheme rather than connecting directly to the PC104 bus

CONS

• Increased design and testing workload

• Increased cost to implement (PCB + Parts)

• Increased system complexity

• Decreased system reliability

• No increase to cool factor

Concept 2 – Only use SBC

PROS

• Simpler to write software for only one platform

• Less parts

• Less cost

• Less development time (hopefully)

CONS

• SBC will have to have another program to manage communications which will increase demands on the SBC processor and operating system resources

Estimated BOM

[pic]

Figure E4.2

Conclusion

We will be using the SBC to implement every function on the robot that it can conceivably do successfully. It is worth difficulty here to avoid the difficulties of including dedicated hardware. This also benefits the customer since they will never need to worry about changing software in a microcontroller and can focus on higher level research.

5) Coordinate Storage

Overview

Below are the requirements for coordinate input to the RP10A.

Test 2: This test will be conducted on a 10' x 10' tiled open floor (e.g. the floor in 09-2230).

1. The team will be given five x and y coordinates (in inches) by an instructor.

2. The values must be inputted into a program already written for device RP10A. After it is received by device RP10A, all connections must be severed. This step must be completed in 120 seconds or less.

3. Device RP10A must autonomously navigate to each coordinate, in order, stopping for 10 seconds at each.

[pic]

Figure E5.0

To meet these needs, the platform will need software to receive the data and store it until the completion of the test. Next, the Pugh chart showing the ratings of criteria needed to meet this requirement.

Selection Stage

[pic]

Figure E5.1

Break Down of Selection Criteria

Cost - The criteria rates to cost to implement the concept. RAM receives a rating of 3 since there is RAM onboard and therefore will not have a cost advantage/disadvantage. The flash option may have a slight cost over RAM depending on the specific implementation which is difficult to analyze at this point since the specific SBC is not known.

Development Needed - This refers to the amount of development that will be needed to arrive at a successful implementation of the concept. The RAM solution will be very easy to implement since there is no added software complexity to implement. Everything that comes into the system will be in RAM at one point or another. The flash concept will require special I/O handling code to store the information on the specific flash implementation. Most likely this will be file I/O operations but again, since the SBC is unknown, it is tough to say with certainty.

Programmable Ease - This ties in with development but focuses on maintainability or how easy it is for someone to modify later in time. The RAM received a rating of three since it will neither help nor hinder a developer in the future. Flash gets a two because the mechanisms for storing the data will already be in place and the developer may only need to modify a few lines of code to change storage media.

Customer Ease of Use - This is an important consideration, however since this aspect of the platform should be transparent to the user, both receive a three.

Robustness - This is the reliability of the storage method with flash having a distinct advantage over RAM since the RAM contents will be lost upon power loss. However, there is no requirement for the data retention and therefore this criterion receives little weight.

Concept 1 - Flash

PROS

• Coordinate storage will be safe in the event of power loss

• Software “hooks” will be in place should anther storage scheme be desired in the future; easy upgrade path

CONS

• Possibly increased cost if user wants to store data off SBC

• Increased software development time required

• Increased software complexity

Concept 2 - RAM

PROS

• Simple, data will already be in ram when received from PC

• Cheap

• No extra development time required

• Minimal code to write to support this concept

CONS

• Data lost if power fails

|Cost of External Flash () |

|Implementation |Capacity (MB) |Cost |

|USB Flash |128 |6.99 |

|Secure Flash |128 |7.99 |

|Compact Flash |256 |11.99 |

Figure E5.2

*It is assumed that the SBC has the ability to communicate with at least one of these technologies, but the specifics of the SBC are unknown at this time.

Conclusion

We have decided to continue with the RAM concept for the storage of coordinates unless we decide that we need the robustness of the flash storage. The actual implementation will probably be along the lines of the following: A simple guidance program will be started on the RP10A which will wait for the reception of coordinates from an upstream PC. Once received the RP10A will disconnect from the PC and wait until a signal is met for the robot to begin its test.

6) Remote kill Switch Concept Comparison

Overview

Safe operation of the robotic platform is of paramount concern. In the event that an operator or bystander needs to terminate the robot in a timely fashion, there must be a remote kill switch. Below is the concept selection for the kill switch. We examined four different configurations as well as combination of concepts before arriving with the best solution.

The solution we have found to be the best fit is a kill switch tethered to a remote. The remote is the user interface to the robot. The kill switch will be connected via wires to the remote which is connected with wires to the robot. During the autonomous test, the remotes functionality will be disabled but the kill switch will still be functional.

We considered keeping the kill switch on the remote but then bystanders will have poor access. We also considered wireless solutions but consider them less reliable and hence less effective.

Concepts Explained

On Remote - Kill switch is located on the remote control which is wired to the robot.

Stand Alone T. - Kill switch is a box that is wired to the robot, not connected to the remote.

Stand Alone W. - Kill switch is a box that triggers a system on the robot via a wireless link.

Voice Activated - The robot will be equipped with a voice recognition system that is triggered by screams of imminent doom.

T. Hybrid - Best solution, there are two remote kill switches. One on the remote and one tethered to the remote; perhaps the tethered switch is controlled by an OSHA representative.

W. Hybrid - Stand alone wireless kill switch as well as a kill switch on the wireless remote.

Selection Stage

[pic]

Figure E6.0

Break Down of Selection Criteria

Development Time - This is the time it will take the design team to develop the concept including all testing and prototyping.

Reliability - This is how much the concept can be counted on to carry out its task. This is an important criterion since safety is a paramount concern.

Wow Factor - This criterion rates the ability of the concept to impress a bystander.

Safety - This criterion rates how well the concept contributes to the overall safeness of the platform.

Range - This criterion rates how far the concept would be able to effectively control the robot from.

Effectiveness - This criterion rates how well the concept implements the safety requirement set out in the needs document.

Selection Stage

[pic]

Figure E6.1

Concept A - On Remote

PROS

• Not much development needed

• Cost effective

• Very safe

• Reliable

CONS

• Only operator can stop robot

• Restricted range by the tether

Concept B - Stand Alone Tethered

PROS

• Can be operated by bystander or dedicated personnel

• Very Safe

• Very Effective

CONS

• More development time than concept A

• Higher cost than concept A

Concept C - Stand Alone Wireless

PROS

• Wow factor because wireless is cooler than wired

• Good level of safety

• Best range

CONS

• Long development time due to the complexities of wireless communications

• Lowest reliability due to the complexities of wireless communications

• Highest cost

Concept AB - Tethered Hybrid

PROS

• Most safe concept because it provides two ways to kill robot operation

• Most effective method because tethered connection allows most resilient connection to robot

CONS

• Longer development time since there is a need to develop both a kill switch on the remote controller and a standalone kill switch box

Concept AD - Wireless Hybrid

PROS

• Best wow factor

• Highly effective because stand alone kill switch acts as back-up to controller kill switch

• Excellent range

CONS

• Longest development time since we would need to design two separate wireless communication links

7) Software

A. User Interface Software Concept Selection

Overview

Here are the concepts for the software selection. There are two realms to consider the software for. One is the software that will be used on the PC which the user uses to input coordinate data to the platform. The other is the software that is running on the platform that will receive the coordinate data and control the robot as it moves to the coordinates.

Screening Stage

[pic]

Figure E7.0

Selection Stage

[pic]

Figure E7.1

Conclusion

For the software that the user will use to input coordinate data and that runs on the PC, LabView is the clear winner. LabView is a premier software package that is extremely fast to develop and easily maintainable. It is very easy to create elegant and highly functional graphical user interfaces using LabView. Visual Basic is a popular graphical programming language but out group does not have much experience with this platform and therefore it scores worse than LabView.

B. Platform Software Concept Selection

Screening Stage

[pic]

Figure E7.2

Breakdown of Selection Criteria

Cost- This consists of total cost of the software package of each option.

Time requirement- This consists of the programming time required to get each option to work

Ease of Implementation- This is the difficulty in arriving at a software solution

Maintainability-This is how easy it will be to someone to modify the code at a later date

Team Experience-This rates the amount of experience on the team

Debug-This rates the quality of the debugging features available for the language

Number of Features-This rates how many tasks can be supported within the language

Resource Requirements- This consists of how much memory will be required to run each option.

Portability- This consists of how easy the program will be able to be interchanged between different operating systems.

Wow Factor- This refers to how impressive the user interface will be to the user.

Selection Stage

[pic]

Figure E7.3

Conclusion

The software that runs the platform will have three main functions. It will receive user input from a PC that will contain coordinate data, receive user input from a remote controller and it will need to be able to guide the robot by issuing the correct commands to the motor control software. It initially look like the best solution will be to use a shell language like BASH to call small functions and programs written in C/C++. This presents many interesting problems but it we think that the overall system will be easier to build in this manner. Not the least of the reasons is the shells ability to pipe data which is critical to platform control. It is a involving process to do this in a compiled language. Therefore, someone with the most basic C/C++ experience can write a simple program that will be called and controlled from the script. Data flow can be handled by the shell rather than inter-process communication which presents its own difficulties.

One screaming shortcoming of a shell language such as BASH is that there is no floating point math integration. This weakness actually highlights its strength. BASH can call an external program (such as ‘bc’) and take that output and pipe it to where it is needed. Complex mathematical computation can be accomplished with a shell in this manner.

8.) Back Plane Power Connection Concepts

Overview

The Lynx 586 SBC and daughter boards will be placed inside a mechanical box. There must be power provided to these boards inside the box. The solution to provide power should be user friendly, and robust. After looking at several different solutions, the most feasible and best solutions would be an ATX connector, a PCB connector, or a Military Spec. connector. These solutions can be seen in Table 1.1.

Screening Stage

[pic]

Figure E8.0

Selection Stage

Following the Pugh Chart guidelines, a reference design was chosen to which all other designs were rated. The ATX connector was chosen as the reference design because it will be needed in both other concepts, and is also readily available , simple to implement, and cheap.

[pic]

Figure E8.1

In the second Pugh Chart, each selection criteria was given a weight and each method a weighted score. It was decided that the PCB connector and Military Spec connector are worth looking farther into for prototyping.

Break Down of Selection Criteria

Cost- This subcategory deals with the cost of developing and/or purchasing each solution.

Development Needed- This subcategory deals with the time of development that it would take to integrate the solution into the power backplane.

Customer Ease of Use- This consists of how easy it is for the end user to disconnect and reconnect the electronics of the robot to the platform, in a timely manner.

Robustness- This subcategory deals with how well the backplane holds up after several uses. The user should be able to connect and disconnect several hundred times without effective wear on the connector.

Off the Shelf- This subcategory deals with the availability of the parts, and the least amount of custom work that needs to be done to create the solution.

Concept 1 – ATX Connector

[pic]

Figure E8.2

PROS

• Implementation cost- can be bought pre-made

• Cost- low cost around $5

• Form Factor- plugs right into Lynx 586 SBC and daughter boards on 8-pin side

CONS

• Not robust – plastic connector not meant to disconnect and reconnect several times

• Not easy to use- difficult plastic locking to disengage with fingers

Concept 2 – PCB Connector

[pic]

Figure E8.3

PROS

• Fully customizable- Can use any surface mount connector, and can also incorporate any other custom circuitry onto the PCB

• Robust- Connectors are more heavy duty, mounting holes to screw into back of box.

• Ease of Use- No locking or unlocking

CONS

• Cost- PCB material, connectors, screws, ATX cable all included in cost

• Development – Must design PCB layout

• Off the shelf- PCB would be custom designed

Concept 3 – Military Spec Connector

[pic]

Figure E8.4

PROS

• Robust- These are military grade connectors used in all the armed forces

• Off the shelf- Already built

CONS

• Development- Adaptor cable needs to be made to connect to 4-pin ATX connector

Conclusion

The PCB and Military Spec both seem to be the best solutions so far. Both provide a robust, user friendly solution for providing power to the electronics. Both of these solutions however will also use the ATX 4 pin to 8 pin connector. Further research must be performed to find the optimal solution.

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Circuit Breaker

Hot Plug

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