Sarah Philo

Project Identity: Classic Rocker, Week 1, 1/25/06

Work Completed:

Before break, Adam, Tom, and I went to Linens n’ Things to purchase the pre-fabricated chair that we plan to motorize. Tom purchased speaker wire from Radio Shack, and we placed and received an order for our squish switch from TFH. We also placed orders for our Boss Audio CD-3020 CD player and two MA Audio HK35 speakers from www.onlinecarstereo.com, but there was a problem with their shipping policy, so we found out when we got back that we needed to find a new vendor. This was a fairly large setback, because we need to determine the current draw of the CD player in order to purchase our power supply and our push button switch. This week we placed a new order for the CD player and the speakers, analyzed the exact shape and rocking motion of the chair in order to determine the specific stresses on the frame, and tested the motor by hooking it up to a power source to ensure that it worked. To analyze the chair, Adam and Tom took pictures while I rocked the chair to two different positions: one that would be comfortable when initially sitting, one that was rocked backward comfortably. We then measured the distances between the top of the chair and the floor from each position, measured the dimensions of the chair, and Adam inserted our calculations into Working Model 2D to determine the exact forces that should be placed on the frame. From these calculations, we determined the shape and size of the frame. It has been decided that we will use 80/20 extrusions for our frame, so we used their Auto Cad program to design it.

I researched switches, but then realized that current flow to the switch is a determining factor when deciding which product to purchase. Another potential factor is that many of the websites selling SPDT pushbutton switches have a minimum quantity of many more than one or a purchase price that far exceeds the price of a single switch. I also found a website where we can get the box for our touch switch, and also a casing for the CD player to insulate it from the aluminum we are going to use for the control tower. The company, OKW Enclosures, sends free samples of their products, so I am fairly certain we can obtain these cases for free.

ID / Task_Name / Duration / Start_Date / Finish_Date
1 / Semester Starts / 1 day? / Tue 1/17/06 / Tue 1/17/06
2 / Inspect Parts / 2 days? / Tue 1/17/06 / Wed 1/18/06
3 / ELECTRICAL TESTING / 3 days? / Wed 1/18/06 / Fri 1/20/06
4 / Determine Current Draw of Motor / 1 day? / Wed 1/18/06 / Wed 1/18/06
5 / Determine Current Draw of CD Player / 3 days? / Wed 1/18/06 / Fri 1/20/06
6 / Determine Appropriate Power Supply / 1 day? / Fri 1/20/06 / Fri 1/20/06
7 / Order Power Supply / 1 day? / Fri 1/20/06 / Fri 1/20/06
8 / CHAIR ANALYSIS / 6 days? / Wed 1/18/06 / Mon 1/23/06
9 / Determine Reallife Centers of Mass to Compare with Experimental / 3 days? / Wed 1/18/06 / Fri 1/20/06
10 / Calculate Optimal Hinge Position / 3 days / Fri 1/20/06 / Sun 1/22/06
11 / Inspect Chair Frame Before Designing Reinforcements / 3 days / Fri 1/20/06 / Sun 1/22/06
12 / Determine Comfortable Rocking Displacement / 1 day / Mon 1/23/06 / Mon 1/23/06
13 / Determine Comfortable Rocking Speed / 1 day? / Mon 1/23/06 / Mon 1/23/06
14 / FRAME CONSTRUCTION / 10 days / Mon 1/23/06 / Wed 2/1/06
15 / CHAIR FRAME CONSTRUCTION / 10 days / Mon 1/23/06 / Wed 2/1/06
16 / Finalize Design of Internal Frame Reinforcements / 2 days / Mon 1/23/06 / Tue 1/24/06

Future Work:

This week we plan to finalize and order our frame pieces from 80/20 Inc., hopefully test the CD player current draw, provided it comes in, so that we can order our power supply and switches, and then begin wiring it to the speakers and determining how to wire the switch into the mute function. We like to start analyzing and designing the setup to gear down the motor if the CD player and speakers do not come in this week.

16 / Finalize Design of Internal Frame Reinforcements / 2 days / Mon 1/23/06 / Tue 1/24/06
17 / Cut Parts for Internal Frame / 7 days / Tue 1/24/06 / Mon 1/30/06
18 / Weld Frame / 5 days / Thu 1/26/06 / Mon 1/30/06
19 / Attach Frame to Rocker / 2 days / Tue 1/31/06 / Wed 2/1/06
20 / BASE FRAME CONSTRUCTION / 7 days / Thu 1/26/06 / Wed 2/1/06
21 / Finalize Base Design / 3 days / Thu 1/26/06 / Sat 1/28/06
22 / Cut Parts from Aluminum Stock / 3 days / Mon 1/30/06 / Wed 2/1/06
23 / Weld Base / 2 days / Tue 1/31/06 / Wed 2/1/06

Because we are going to use 80/20 extrusions, most likely, we will order the pieces for the frame and begin constructing it using braces from a hardware store, either Lowe’s or Home Depot. Until we receive the equipment we need, we will continue to look ahead in the timeline to begin completing the tasks we can while we wait.

Project Review:

Thus far, we are a little set back because we haven’t received the parts we need to begin making significant progress. However, because we plan to use 80/20 extrusions, constructing the frame should take much less time than planned. Also, we are beginning to work on future tasks while we are waiting for the equipment to complete current tasks. Overall I think that we are on schedule or a little ahead.

Hours Worked: This week I worked for about 8 hours.