2009:Electrical 1.13.09

1.13.2009

Start time: 7:00 pm

End time: 9 pm

Members present: Rika, Sean, Crystal, Michael, Apples, Oranges

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Tasks Completed:

• Tested Banner Sensors for effectiveness with ball sensing
  
• Seems to be a relatively low chance of a false negative
  
• False negatives can be avoided by using multiple sensors for detection of a single ball
  
• Cleaned up wiring mock board
  
• Connected and extended PWM encoders on mock board
  
• Met with programming and various teams regarding sensor feedback.  The general consensus is to account for all sensors and remove them as we find they aren't being used.

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SENSOR BREAKDOWN:

ABSOLUTELY NECESSARY

• Ball flipper (at top of conveyor, used to select shoot/hopper) - most likely a small shaft encoder TBD.  If we're shooting, we want the flipper to be at the appropriate speed before we push the ball upwards, since motors don't get to the desired speed instantaneously.
  
• Trap doors - two limit switches per motor used for door - likely leaf switches provided in KoP.  Sure you could use one switch to detect open/closed, but if you have two switches per door, you can detect open/closed/in-between...
  
• Ball stop sensor - most likely a pair of Allen Bradley 7000 series banner sensors (beam break).  This is used to detect if a ball has reached the top of the conveyor column.  It's functionality is similar to ROFL-Bot's ball stop sensor.  It is basically there to allow the programmers to know that a ball is there and is ready to be shot.
  

NICE TO HAVE

• "What-Ball-Position-Is-Filled-In-Conveyor Sensor". This would be very niceand quite easy.  This would allow for the programmers/drivers to know how full the conveyor is.  this  The design of the conveyor system is supposed to keep on pushing balls into it until we reach "best case" scenario, being that the (or both) entire columns are filled to the top.  - likely a pair of Allen Bradley 7000 series banner sensors per ball
  
• Encoders for the two conveyors.  This seems like it would be a nice to have but not necessary.  [please add any comments why it is "absolutely necessary"]
  

WILL WE NEED THESE?

• Shaft encoders for idler wheels...  Haven't heard back if we'll need these.
  

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Tasks In Progress:

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Tasks to Complete:

• Figure out the best orientation for the main battery (talk with drivetrain, and electrical team as they will likely be the ones changing batteries most often) and attach the hardware to the batteries to best match the battery orientation when in the chassis.
  
• Josh Gannon mentioned trying to flesh out an area to mount electronics and how to shape our boards to maximize strength...  Work with him on this re-design.
  
• Interface with Omron Photosensors and figure out if they are sufficient for conveyor encoders.  We should also find app notes on these, to see some examples of how they are used.
  
• Reasearch/Investigate how to mount/put together the US Digital encoders in the KoP.  Also try to find similar encoders.
• Does programming drive train team want to control coast/brake on speed controllers?  Does programming mechanical want to control coast/brake on speed controllers?  Account for this in the next task.
• How many digital inputs are we going to need?  Can we use only one side car?
• Re-crimp the 6AWG wire to the power distribution panel on the mock board.
• Sean Kemp MUST upload the BOM excel file to the wiki.

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Images & Additional Updates:

7000 Series Banner Sensor

Omron EE-SPY415

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