Weekly Report February 26, 2010 Multifunction Table & HANSS with Biofeedback By Mark Galiette, Liz Hufnagel, Daniel Tichon Team #1 Project for Client: Annalee Hughes Client Contact: Susan Lucek, slucek@nerac.com, (860) 872-7000 ext. 1008
1. Mark Galiette Weekly Progress 1.1 Work Completed Since the last weekly report, I have completed further work on the electrical components and enclosures of the RF Receiver and RF Transmitter. On February 19 th, I began to propagate the RF Transmitter circuitry on a generic PCB board purchased at Radio Shack. First, I obtained duplicate electrical components so the original circuit on the protoboard would provide a visual guide. Next, all components and necessary wiring for the LM317T voltage regulator, 8-pin socket, relay, audio input, and audio output was arranged and soldered onto the PCB. Next, on February 20 th, I continued to work on the custom PCB for the RF Receiver using National Instruments Multisim and Ultiboard. Below, Figure 1 depicts the RF Receiver PCB as completed to this date. Component J1 is the connection for the RF Receiver module, U1 and U2 are the 2N222A transistors, S1 and S2 are connections for the vibrating motors, U3 is the LM317T voltage regulator, and U4 corresponds to the 8-bit decoder. Figure 1. RF Receiver PCB Created Using National Instruments Ultiboard. By using a custom PCB, the PCB dimensioned approximately one inch by one inch. However, during the conversion process between Multisim and Ultiboard, some connections were not added to the PCB. This problem can be attributed to the way the components are arranged on the PCB. Rearranging the electrical components will correct this problem. Furthermore, no appropriately sized battery holder could be added to the PCB. To remedy this situation, I will incorporate pinholes into the PCB and wire the current 23mm battery case to the PCB. On February 22 nd, I completed soldering the remaining components of the RF Transmitter circuitry on the generic PCB. The remaining component and wiring were positioned and soldered for the RF Transmitter module, battery with On/Off switch, and biofeedback switches. Below, Figure 2 displays the completed RF Transmitter on a generic PCB. Next, I tested the completed RF Transmitter circuitry using audio input from an ipod, audio output to a
pair of headphones, the vibrating of the vibrating motors as the output when no buttons are depressed, and varying pressing all three of the biofeedback switches. Testing proved all soldered connection and electrical components were correctly connected and soldered. Figure 2. RF Transmitter on Generic PCB On February 23 rd, I modified the RF Transmitter generic PCB and plastic enclosure. In order to fit the PCB into the plastic casing, I removed a 3/8 inch by 1/2 inch section of the generic PCB using a Dremel with grinding wheel attachment. Next, I modified the plastic enclosure to accept two 3.5mm headphone jacks and a sliding On/Off switch. Using a drill press with 0.25 inch bit, I drilled out two holes. To accommodate the On/Off switch, I used the Dremel, with cutting attachment, to cut a 5/8 inch by 3/4 inch rectangle. Next, I secured both 3.5mm audio jacks into the two-drilled holes, using a tightening washer, and the On/Off switch into the rectangular cutout with epoxy. Finally, I tested the entire circuitry, using the testing sequence used on the previous day, to ensure the modifications did not adversely affect the circuit. Figure 3 displays the completed RF Transmitter enclosure.
Figure 3. Completed RF Transmitter Enclosure 1.2 Future Work For the HANSS with Biofeedback electrical circuitry, I plan on completing work on fabrication of the RF Receiver housing, integrating the biofeedback switches into the HANSS, and finalizing the custom PCB design. Fabrication of the RF Receiver housing was supposed to occur this week, however, completing the RF Transmitter housing will allow Liz and I to incorporate the biofeedback switches into the HANSS. Then, Liz can field test the device with the client and determine if the design functions correctly. Finally, finalizing the custom PCB design allows me to order the PCB before going on Spring Break, giving the manufacturer two weeks to create the PCB. 1.3 Hours Worked Since the last weekly report, I have worked about twelve hours on the HANSS with Biofeedback electrical circuitry. 2. Liz Hufnagel Weekly Progress 2.1 Work Completed On Friday 2/19 I worked in the model shop to fabricate the vertical shaft attachment piece for the HANSS. According to the representatives at Pride Wheelchairs, the size of the shaft for Annalee s new wheel chair will be a 1 2 x 1 2 square. This information was determined by directly calling the vendor and speaking with a technician in November of 2009. Parts that we had acquired from Neat Marketplace would not fit this new shaft size. I decided to adapt the circular ball head of an oval notched vertical shaft to a newly fabricated square shaft. I used the vertical cutter to cut 18 of stock aluminum for the new shaft. The dimensions were approximately 1 2 x 1 2, however, later adjustments may need to be made using the miller. Next I used a band saw to file away the protective coating on the Neat Marketplace oval shaft. The protective coating needed to be removed for the welding process. I next used the vertical cutter to cut the circular ball head off of the Neat Marketplace oval shaft. I used the band saw to shape and level the ball head base. I next worked with Serge to align and weld the circular ball head to the aluminum shaft. Figure 4 shows the vertical shaft with ball attachment.
Figure 4. Vertical Shaft With Ball Head Attachment. After welding and cooling the ball head I attached the gooseneck and HANSS to the vertical shaft bar to ensure that all parts properly fit. Figure 5 shows the HANSS with the completed gooseneck attachment and vertical shaft. Figure 5. HANSS With Vertical Shaft and Gooseneck Attachments On 2/19 I also began to sand the Plexiglas table top for paint preparation. I used medium grit sandpaper and a wooden block to roughen both surfaces of the Plexiglas table top. A sticky residue was on the surface in two large locations and will need to be removed, as the sandpaper did not adequately remove them. On 2/19 I also made a trip to JoAnn Fabric located in Manchester to purchase additional nylon fabric, heavy duty snaps, needles, and thread for fabricating the HANSS cover and attaching the chin support. On 2/24 I made a trip to Mansfield Supply to purchase paint for the table and the
HANSS. I purchased Rust-o-leum plastic primer and a cherry red rust-o-leum paint for covering the Plexiglas table top. I also purchased Goof-off in order to remove a sticky residue that was left on the Plexiglas from our original purchase. I also purchased a black protective spray coating to cover the aluminum components of the HANSS. I will begin painting on Friday 2/26. On 2/25 I spend time adjusting fabric positioning and pinning the nylon fabric to determine the dimensions and shape for the fabric cover. I used large needle pins to stretch the fabric tightly around the HANSS. I then carefully peeled the fabric down the arm flange to keep the fabric in the same shape. I used cross-stitch with a 4 times thick threaded needle to sew together the outline of the HANSS shape. I will be sewing two flange pieces, which will slide onto each shoulder flange. After embedding the electrical components I will cover the head pillow. The base fabric layer will be made of three individual pieces sewn together. The final covering will be made of one piece of nylon and be removable. On 2/25 I also spend time determining the placement of the electrical components. The three switches will be arranged so that the end of the switch arm faces down. The switches will be place on the lower portion of the head pillow on the left, right, and center. The component box will be mounted on the rear of the stainless steel frame and then covered with foam. On 2/26 Mark and I will begin embedding the electrical components in the areas I have outlined. Tape will be used to secure each component in position and then contact cement will be used once the positions are finalized. A meeting with the client will be scheduled once we have finished. 2.2 Future Work I also plan to fabricate an alternate vertical shaft bar. This will require ordering new stock pieces and milling a custom bar to fit Annalee s current wheelchair design. Since the arrival of the new chair is undetermined, I would like to make the product available for Annalee s use as soon as possible, and also be able to troubleshoot any problems with the HANSS on the design of the current wheelchair. 2.3 Hours Worked I spent approximately 12 hours working in the model shop, picking up new components, and fabricating the HANSS cover throughout the week. 3. Dan Tichon Weekly Progress 3.1 Work Completed The work for the past week has focused on completing the upright support so that it will be able to move freely up and down with the linear actuator. On February 19, I continued to fabricate the parts required for the moving upright support. A 0.2 inch diameter bolt hole was drilled at the top of the inner upright support and one side was countersunk to allow the screw head to lay flush. Another 0.25 inch diameter bolt hole was drilled in the bottom of the outer upright support tube for the lower attachment of the linear actuator. Both of these holes were offset from the center of the tube by 0.0625 inches due to the specifications of the linear actuator. I also drilled and tapped two 6-32 holes for screws that will hold a thin metal band in place around the Delrin strips. A 5/8 inch hole was drilled through one side of the outer upright support at the top to hold the anti-rotational pin. All of the parts were then assembled without the Delrin strips and the linear actuator was preliminarily tested. Once it was determined to work correctly, the Delrin strips were glued around the outside of the inner upright support. The metal band was attached around the lower end and the screws were inserted to hold it in place. I also started to work on fabricating the hand knob from a block of aluminum
by milling the round neck. All of the pieces were then de-burred and cleaned for future use. This work took 4.5 hours. On February 22, I used the belt sander, files, and sandpaper to shape the Delrin strips so that they would fit inside the outer upright tube. It was determined that the even with several adjustments, the metal band was hitting the side of the tube and preventing free movement. This band was taken off and it was found that the glue had sufficient holding power to not need other support. The parts were then cleaned and dusted so that the full upright support could be assembled. The linear actuator proved to work successfully in raising and lowering the support but it may not have enough power to raise the full table. Figure 6 below shows the linear actuator assembled in the upright support and the attachment bracket ready to be adjusted to the proper height. It was also determined that spacers at the bottom of the linear actuator attachment would be needed to ensure proper alignment. I then started to mill a rectangular block of aluminum to be used as the spacers of the approximate size of 2 x 0.75 x 0.75. This work took 2.5 hours. Figure 6. 1- Upright Support support With with Attachment attachment Bracket brac On February 23, I cut the aluminum spacers to size on the bandsaw and then milled the edges to make them square. The two blocks were milled to be 0.9375 inches long and 0.5 inches square. A 0.24 inch hole was then drilled through the length of the spacers and the corners of the blocks were milled to form them into octagonal tubes. The ends were belt sanded until the precise fit was found for both spacers. The linear actuator was then assembled with the spacers and the full upright support to ensure everything was working correctly. The spacers and the linear actuator can be seen below in Figure 7. After this, I cut the aluminum block for the hand knob to the correct length using the bandsaw. Both ends of the hand knob were then milled to make it the proper thickness without being too heavy. A 0.5 inch hole was drilled through the center of the hand knob so that it could be tapped later. This work took 3 hours to complete.
Figure 7. 2- Spacers in in Outer outer Upright upright Support. support. On February 24, I continued to mill the hand knob by milling a 0.25 inch deep circular groove around the face of the knob. I also resurfaced both faces of the knob so that it would be smooth and easy to grip. I tapped a 1 2-20 hole through the knob and cleaned it of grease and debris. I fit the support rod in the threads by cutting the threads deeper and drilling half of the hand knob hole out. This allowed for better clearance of the threads while giving maximum power. The knob was worked until it was able to spin smoothly on the support rod. I also belt sanded the top edges so that they weren t sharp and would be easy to handle. The finished hand knob and support rod can be seen in Figure 8 below. This work took 1.5 hours to complete. Figure 8. 2- Hand Knob knob and Support support Rod. rod The entire upright support can be seen in Figure 9 below, complete with the linear actuator and attachment clamp.
Figure 9. 4- Full Upright upright Support suppo 3.2 Future Work The next step for the multifunction table will be to lighten as many components as possible without losing structural strength. This will allow the linear actuator to not have to work as hard to raise the table and will give it more power. The pin system will also be fabricated and installed on the upright support after some small adjustments of the inner support. All bolts will be cut to the proper length and the edges will be rounded so there are no potential areas for injury. There are many small adjustments and modifications that will need to be done to ensure proper function and safety of the multifunction table. After these tasks have been completed, it will be necessary to determine the exact dimensions for the table area and the attachment site. This will allow the table to be cut to the final size and then completed. Since the client does not know when they will receive the new chair, as many steps as possible will be done before finalizing the dimensions. 3.3 Hours Worked In all, I have worked approximately 12 hours in the past week on the upright support for the multifunction table.