After taking a break on Wednesday,

Hey grab gang,

Suction Progress: Got suction cups! Got impeller out of vacuum Did some preliminary tests with suction cups on the big vacuums Only held so well with 2 suction cups Had issues with seals - to be expected of a preliminary test

Velcro Progress: Fixed cylinder problems (mostly) Made new pushbar that goes all the way down to the wood backing Did a little more testing Video with pushbar (not the one that has holes for bolt heads though): IMG_4432[1].MOV 1.97 MB View full-size Download

This worked better than yesterday's video. As you can see, we probably need longer cylinders. The holes in the bar for bolt heads will also help because they allow the bar to gain more momentum before contacting the hatch panel.

Talia Nesin Talia also bought stronger velcro after today's meeting so she is going to bring it in tomorrow.

BIG IMPORTANT ANNOUNCEMENT: After today's meeting, I have decided to drop the suction part of the grab hatch project. The reasons are as follows: Suction has proven to be much harder/more complex than we initially thought. Due to this... Suction will most likely not be ready by MVP due date Suction has not shown any more potential than velcro Suction and velcro both held about the same (velcro was actually a little better but I attribute that to poor seals when testing suction) We cannot easily preload a hatch panel with suction Can't have a motor running to hold the hatch panel before a match Would require an additional complexity

So today we: Discussed motor types and gearings For the elevator belt we will use a single 775 geared 25:1 on each elevator will lift us up in 1 second This equates to about a 5 second climb (down, drive, up, drive, up a tiny bit), maybe even less For the wheels, we are thinking of using just 1 775 each, but need to make sure there are no problems with this (stalling, speed, ect) Have not calculated the gearing for this yet (next meeting) Discussed Sensors We are going to use limit switches on the elevators The limit switch will be stored within the top 2X1 crossbar hardstop, and between the bottom plate hardstops and in the side 2X1 tube mounted to the frame Discussed elevator sliding methods Roller Bearings Decided to use .5 in roller bearings Used them last year with no issues We know how to get them to slide smoothly Delrin Sliders Decided against using delrin sliders as they have more friction than roller bearings No need to do them when we already know how to make roller bearings work We CADed The basic structure of the elevator is complete and functional All of the gussets and bearing mountings are complete All of the bearings are mounted

Next meeting we will: Continue CAD Three main things Figure out pulley mountings Figure out motor mounts and sensor mounts Figure out wheels Also add rivets to ensure that there is no interference CAD of iteration one will be done by Saturday morning, when we will go over the CAD with a technical mentor Do math for wheel motors On Saturday we will: Do a design review with technical mentors Start cutting and facing all the 2X1 we need for first elevator Create layout for plates on one sheet We will start queuing for CNC immediately after drive is done, as long as hatch doesn't need it