A Laser Pointing Device to Augment Communication for People with ALS (2017) Gordon Fabian (clips-john Wauer)

Transcription

1 A Laser Pointing Device to Augment Communication for People with ALS (2017) Gordon Fabian (clips-john Wauer) rev: October 2017 [NOTE: The technology of laser modules has greatly improved from the ones that we used in the in the 5/22/2013 original Pointing Device project. They have gotten smaller, and require less voltage and power to operate. The following describes a new Laser Pointing Device design which takes advantage of these laser module improvements. The ALS Association, Iowa Chapter requested that Rockwell Collins Retiree Volunteers (RCRV) adapt and construct laser pointer devices to assist people with ALS to communicate. The device is modeled after a similar device described in "Instructions for a Simple Adaptive Laser Pointer for Low Tech Augmentative Communication" by Margret Cotts, MA, ATP, Assistive Technology Specialist, The Treatment and Research Center at USCF University of California, San Francisco. This version is being built for the third request for devices. We have previously built 2 batches of 10 devices each. This request is for 20 more, Material per unit: - One each: Two AA battery holder case with an ON/OFF switch. Purchased on ebay - Six ft each: 22 GA Gauge Red Black 2 Conductor Speaker Wire Audio Cable. Purchased on ebay. - One each: 1mw 650nm 3VDC Focusable Red Laser Diode Dot Module. Purchased on ebay. For safety, use a one mw or less laser. - Two Zip ties: To fasten wires to the laser mounting clip and provide wire strain relief inside the battery case - Two inches each: ½ inch shrink tube. - One inch each: 3/8 inch shrink tube. - 1 ½ inch 1/8 inch shrink tube. - Laser glasses clip: Built as shown later in this document. Building instructions: Clip: An eye glass clip rearview mirror for bicyclists may be adapted to hold the laser. The one described here is an adaptation designed specifically to hold the laser unit. The eye glasses clip is made of "piano wire" inch or 1.19 mm diameter. The drawing shows the dimensions of the clip. One clip uses approximately 8 1/8 inch of wire. It is best to start with the circular bend which is formed over a 1/4 steel rod. Bend the two circular arcs first with 5/8 inch separation and then bend the circle arcs so they form parallel planes and are lined up so the laser barrel can fit inside. Then complete the other bends. The arcs must be adjusted to make a tight fit with the laser unit barrel. Figure 1. Eye Glasses Clip dimensions The temple tabs on the clip must be bent so they may slide alternately outside and inside the eye glass temple with a firm fit. Two on the outside and one on the inside of the temple. For users without glasses, a Velcro strip may be used as shown in Figure 25 below so pointer may be attached to a hat. 1

2 Figure 2. Clip with laser installed Figure 3. Clip Electrical: The battery case may be used as is with the existing wires spliced into the wire going from the laser to the battery case. For esthetics and durability I chose to remove the existing wires and connect the wires from the laser directly inside the case. The following are the instructions to do that. Open the battery case by sliding the cover off. Do not pry up on it. Note: There may be a small screw holding it on, Figure 4: Battery Case Pop off the cover over the switch. It is held on by melted plastic posts coming through it. A pocket or Exacto knife works great to pop the melted parts. Leave enough post so that they can be melted again to hold the cover switch on. Figure 4. Battery Case with switch cover removed Remove the switch and Negative battery contact 2

3 Figure 5. Battery Case with switch and negative contact removed Run the speaker wire through the hole in the case where the red & black wires formally came out. Figure 6: Battery Case wire routing Split the red and black wires a distance of 7/8 of an inch. Figure 7: Wire separation length Cut the black wire ¼ inch shorter than the red wire. 3

4 Figure 8: Wire sizing Strip each wire ¼ inch Figure 9: Wire Stripping Replace the existing red wire from the center contact of the switch with the new red wire. Also replace the existing black wire from the battery negative contact with the new black wire. Figure 10: Connecting new wires Assemble the switch and negative battery contact back into the battery case 4

5 Figure 11: Switch and contact back in place. Add a tie wrap in the corner of the battery case to provide strain relief for the wires. Figure 12: Wire Strain Relief Put the switch cover back on and melt the posts using a soldering iron to secure it in place. Replace the battery cover. This completes the building of the battery case portion. Figure 13: Completed Battery Case Laser Pointer Assembly You can splice the wires from the battery case to the wires from the laser if desired. However, to make a cleaner and more durable finished product, I chose to remove the existing laser wires and connect the wires from the battery case directly to the laser module. 5

6 Figure 14: Laser with existing insulation and wires Remove the black insulation from the laser module. Figure 15: Laser Module with insulation removed Slide a 3/4 inch long piece of 3/8 shrink tube on the wires from the battery case and then replace the existing red and black wires with the wires from the battery case. Make sure you connect the red wire to the red and black to the black. Figure 16: Wires from the battery case connected to the laser module Move the shrink tube to cover the laser circuits 6

7 Figure 17: Shrink tube in place. Shrink the tube with a heat gun. To protect the laser from too much heat, leave the heat on just long enough to shrink the tube. Figure 18: Laser module with new wires and shrink tube in place With the clip legs to the right slide the laser into the clip loop with the wires in front of the legs. Figure 19: Laser module mounted in clip Fold the wires towards the front keeping the two wires centered below the clip. Add a Zip tie to provide a strain relief. 7

8 Figure 20: Wire Strain relief Bend the wires back towards the back of the clip. Keeping them aligned and flat. Figure 21: Wire routing. Since the lasers have the capability to focus the dot shape, now is a good time to do that. Place the two AA batteries in the battery case. Make sure the polarity is correct. These lasers don t like reverse voltage. Point the laser at an object at the distance that the laser will be used and turn front of the barrel for the sharpest dot. It won t be perfect. I focused these at about four feet. To keep the focus from changing during the final assembly, put a small piece of tape across the barrel parts to keep the focus from changing. I cut up some Avery stickers. Figure 22: Tape to keep the focus from changing Position the wires as shown in Figure 21 and place 1 ½ inch of the ½ inch Shrink Tube over the laser. Apply heat to shrink the tube in place. Use a razor blade or sharp knife to trim any tube overlap at the front of the laser. 8

9 Figure 23: Completed laser Pointer section For a more secure mounting of the pointer to the eye glass temple, ½ inch of 1/8 diameter shrink tube was applied to each tab. Figure 26: Laser pointer with tube on the tabs. This completes the assembly of the Pointer unit. Our client requested that we add a small piece of Velcro on each pointer so that they could be used with a hat or head band. I used self stick Velcro and applied it to the side where the wires are. This was the flattest portion of the pointer. Figure 24: Laser Pointer with Velcro attached To keep the Velcro in place, I cut two small sections of shrink tube and applied them at the ends.!/2 inch diameter at the back and 3/8 inch diameter at the front. 9

10 Figure 25: Laser Pointer with Velcro secured. That completes the project. Below shows the units that we have built Figure 27: Completed project ready for shipment. 10