Friday, February 22, 2013

Build Journal (Jordan) 2/22/13

Today I we had a very productive meeting. We Started off on a lead of where to get some materials going to the JEC E-Waste bins where we salvaged some scrap metal that would be useful for the base plate that we needed badly to start work on the chassis. Another really big accomplishment today is that we also got a working H-bridge courtesy of David! look out for his post. Also I will add that we worked out some details on the building of the tanks to how said liquids. at first we though about PVC, but we found that was unnecessarily expensive for this project. The next idea was trying to use sheet aluminum which is cheaper and would make the creation of the drink storage more useful. This plan seemed pretty good but then we'd have to use a lot of gas to weld said tanks and that would be kinda expensive too. Kyle suggested decided that maybe we should go simpler and maybe use the containers that the bottles already come in, which I feel is more in the vein of open hardware because it's easily accessible.  Another plus is that it's light, free, and they are already rated for the amount the pressure that we're going to be working with (it's not like we're trying to make a bottle rocket). The feasibility should be confirmed by next week and then we'll be good to go! We should start construction on the chassis by next week if all goes well. All we need is a shop...


Meeting Notes 2/22/13

  • Todo From Last Meeting
    • get base plate (Kyle)
      • Done
    • Look up rules on welding pressure vessels (Kyle)
      • Not Recommended
    • Line following test rig (Bharath + David)
      • in progress
    • Get Checks (Jordan)
      • Write Check to EHC
    • Send Calendar Out
      • done
    • Blog Post (All)
      • Good
    • Drink Pricing (Dan)
      • Get Approval

  • Todo Next Meeting
    • Talk to EHC about a community Charger (Jordan)
      • Hobby King
    • Look For Wheel (Kyle)
    • Drink Pricing (Dan)
      • Get Approval
    • Motor Dampening
    • Talk to FH or FSAE (Jordan Eric)
      • 80in of tig aluminum welding
    • Usability of a 2 liter bottle (dan)
      • See if we can make a line in for pressure and a line out for the liquid

Chassis update

Here's a quick run through of the preliminary chassis design for Alfred. Looking at what we needed to accomplish with Alfred's mechanical structure, it became clear that the two greatest priorities were keeping it inexpensive and convenient for users to interact with. While some of the concept drawings leaned towards the "R2-D2" aesthetic, it soon sadly became clear that a circular shell would be too pricey for our budget. We briefly explored the idea of bending sheet metal or vinyl around a circular frame, but this introduced much more complexity than it was worth in addition to the cost. One of the most prohibitive factors was shipping costs for such large pieces of material, which is a challenge we are still working on. Eventually we decided to make a relatively simple rectangular box with an internal steel frame. The shell will consist of plastic plates that mount around the outside. This should make the refilling, recharging, and maintenance tasks  easy and quick.


The front and rear casters weren't added yet in the screenshot, it won't actually balance on two wheels. The two motor and gearbox mock-ups are based off the Banebots datasheets, and mount directly to the base plate. The wheels we found online will have to be modified in some way to connect them to the shafts.


Here it is with an angle iron frame. Some example shell plates have been attached to the frame for reference. These plates will probably be waterjetted to create the openings for the drink filling mechanism, motor shafts, and interface panel. Almost none of the internals have been added in yet because the design of those are still being finalized.


Friday, February 15, 2013

Meeting Notes 2/15/13



  • Updates from last meeting
    • Look up open hardware specs (Jordan)
      • Check but we should be fine
    • Post any and all current code to repo (Everyone)
      • None so far
    • Make sure everyone updates the blog (Everyone)
      • Do this
    • Change to Google drive (David?)
      • Did this
    • Decide what we need to buy (Everyone)
      • Base Plate ASAP
    • Mercer lab funding (David)
      • We can use the space
      • Fill out form get free parts
    • CAD base (Jordan, Kyle)
      • Totally
    • Find local supplier (Anyone/Jordan)
      • Process shop for base plate
    • Budget in stainless steel and aluminum (Dan)
      • Work in progress
    • Look in to LED designs (Bharath)
      • Work in progress
    • Line Following algorithms (Bharath)
      • Needs test rig

  • Budget
    • We need to start getting a total budget going
      • Google docs and everyone updates it?
      • Done
  • Chassis/Structure
    • Design and plan out spacing for drink system
    • CAD drink system design
    • Solid Work and it’s Openness?
      • Check again but it should be cool
  • UI
    • Start Deciding on how to implement
  • Todo For Next Meeting
    • get base plate (Kyle)
    • Look up rules on welding pressure vessels (Kyle)
    • Line following test rig (Bharath + David
    • Get Checks (Jordan)
    • Send Calendar Our
    • Blog Post (All)
    • Drink Pricing (Dan)

Motor Testing


So for Alfred today, we tested the two motors we brought at Robotmarketplace. When 8v was applied to the motors, the noise generated from the motor was apparent. The only way to damper the noise is by using Jordan's jacket.
The team decided that the only way to reduce the noise is by visiting Wallmart and buying yoga mats to damper the noise. The team also realized that the motor will not always be powered at 8v since there will be a speed controller implemented for Alfred.

Saturday, February 2, 2013

Quick notes on the Fluids subsystem

    So I sent out an email to David Herbet recently detailing a preliminary parts list for the liquid subsystem. I'll post the entire list later on. For now, lets talk about pressure vessels.

   Alfred needs 5 containers/ pressure vessels to hold the different kinds of soda. These need to be about 2 Liters in volume. Google searching hasn't returned any pressure vessels of this size...at least not any cheap ones. PVC was the first material we considered for building drink containers. Pressure within the containers shouldn't be very high (~30psia, if that) when Alfred is running full stop.

   Schedule 80 would be more than able to handle this pressure. From Harvel's website, schedule 80 is used for potable water systems and is resistant to most acids, bases, salts and aliphatic solutions, so it wouldn't react poorly when in contact with the soda. This seems like it would fit our needs....I haven't checked pricing yet though. McMaster Carr also sells schedule 80. 
http://www.harvel.com/technical-support-center/product-specifications/pvc-pipe-schedule-80

  Jordan recommended looking into sheets of stainless steel or aluminum to replace the PVC. It would be bent and welded to create the size pressure vessel we want. I'll have to figure out what size thickness of stainless steel we'll need to avoid having a blowout once we pump them full of pressure. I also need to figure out how to hold carbonation in the soda.

Concerns:

  • How to hold the carbonation into the soda
  • PVC or metal (aluminum, stainless steel, etc)
  • Sterilize the pressure vessels? 
  • NSF and ASTM materials 
That's all for now

Friday, February 1, 2013

2/1/13 Meeting Documentation

There's Nothing Better to do On a Friday Night than Build Robots 

Meeting Notes 2/1/13

Meeting Notes 2/1/13

  • RCOS
    • Set up Blogger Account
      • Every one should blog their own task and assignments
    • Set up Code Repository 

      • https://github.com/daitomodachi/EHC-Alfred-.git
      • This is where we will put all code

    • Set up RCOS project
    • To-do:
      • Look up Open Hardware Specs (Jordan)
      • Post Any and All Current Code to Repo (Everyone)
      • Make Sure Everyone Updates (Everyone
  • Funding/Budget
    • What We Need to Buy next
      • undecided
    • What We Need to Buy in General
      • Post Excel budgets on the dropbox/google drive
    • To-do:
      • Decided What We Need to Buy next (Everyone)
      • Looking to Mercer Lab as a source of funding (David)
  • Chassis/Structure (Kyle, Jordan)
    • Box v.s. Cylinder
      • Box is easier to construct and will work with existing structure
      • Find local sheet metal supplier
    • Noisy Motors
      • Find a dampening system
    • CAD
      • Decided to use solidworks and work on the base by next meeting
    • To-do:
      • CAD base (Jordan, Kyle)
      • Find local supplier (Anyone/Jordan)
  • Drink System
    • Looked at Budget
      • Pretty Expensive w/ PVC
      • Look at Stainless Steel and Aluminum to weld together for containers (e.g. gas tanks)
    • To-do:
      • Budget in Stainless Steel and Aluminum (Dan)
  • UI
    • Use a Combination of LED's and Push buttons or LED push buttons for interface
    • Use More Sensors
    • Use Speech to alert pedestrians and advertise itself
    • To-do:

      • Look in to LED designs (Bharath)
      • Line Following algorithms (Bharath)

Meeting Note Taking
Meeting Note Taking