Exo Arm Work Night 5.4.17

Exo Arm Work Night

Date: 5.4.17
Location: Logan HS
Time: 3.5 hours (4-7:30 PM)
Students: Alex R., Alex M., Grant, Trent and Ben.
Goal: Begin to wire in the electronics for the Exo Arm.


Our goal of getting most of the wiring done tonight fell short. We spent at least an hour discussing wiring possibilities and exploring the option of a 2 second delay using a 555 timer before the grinder actually turns on. Also, part of the existing wiring for the GFCI had to be redone to allow for another switch and separate receptacle for our 12 V power supply. Regardless we made progress and have a new parts list to pick up.

The good news is the linear blocks that we fabricated (thanks to Mr. Pitz) seem to secure the arm to the rail with no deformity to the rail or block. No bearings are used in these so they will need some grease to work well.

Filing down rough or sharp edges were taken on by Alex R. and Alex M. This is really an important job because in the production of the arm we are sure to have forgotten some sharp edges so having another set of eyes go over it again really helps.

We determined that the wire gauge we will be using is 18 GA to ensure we have enough wire to carry the current without melting anything. Much discussion went into the location of the grinder switch and how it will be mounted. We decided to mount it near the grinder and then experimented with different conduit to see which one allowed for the most freedom of movement. We got some blue plastic tech conduit that we thought would work well but it did not. A piece of metal flex conduit will be used along the bottom of the arm.

The warning light at the top of the rail was wired in to a switch and tested out to perfection. The toggle switch to operate the linear actuator was tested but we could not get it to work. We suspect we have it wired wrong and need a jumper somewhere on it. The circuit for the linear actuator did not work as expected. We need to bring in a 6 V power source for it somewhere.

Work night next week will focus on more wiring and troubleshooting.

Trent stripping wires.

Alex R. filing the arm down.

Ben working with Mr. Foy on the relay circuit using transistors. More work needs to be done on this.

Filing the aluminum base.

Alex M. cutting a piece of aluminum for the grinder switch.

The newly machined bearingless linear blocks.

Trent getting some wires stripped.