BeatMobile (Duke University)

A demonstration of the client using the BeatMobile

This picture shows our client using the BeatMobile.

Allison Finley, Inka Johnson, Drew Masters, Radu Darie

Abstract

The client is an adolescent with Morquio syndrome. Due to his limited mobility, he uses a wheelchair and requires assistance to transport and set up his DJ equipment.  The goal is to construct a device that allows him to do this independently. The BeatMobile features a wheeled cart frame that allows for easy transportation, a lighting system to display lights at an elevated height during shows, and a ramp and winch system for loading and unloading the heavy cart. The BeatMobile significantly reduced the set up time for a DJ show. With this device, less than half of the original set up time is required.  Additional testing confirmed that the winch can pull the cart up the ramp, even when carrying excessive loads.  The average force exerted by the winch to pull the fully-loaded 118 kg cart up the ramp is 473 N ± 18 N. The winch has a 907 kg pulling capacity, so loading and unloading the cart will not be a problem, even if the cart is overloaded. The client was very satisfied with the BeatMobile and plans to use the project at his next gig.  His mother, who previously loaded all of the equipment manually, agrees that it will significantly reduce her workload when setting up for shows.

Background

The client is a high school junior who enjoys playing basketball, mixing music and DJing for events.  He would like to expand his DJ business and perhaps continue it in college.  Because he has Morquio syndrome, a genetic condition which causes stunted growth and limited mobility, the client uses a wheelchair or electric scooter and cannot transport and set up his DJ equipment independently. Three to four people are generally required to help him set up for DJ shows. The client currently owns two active speakers, a mixing table, a laptop, a fog machine, and two large lights. He hopes to add more equipment, particularly more lights, to his collection.  He owns an electric scooter with a trailer hitch receiver that can be used to tow the equipment.  His mentor has noticed that he becomes frustrated when trying to direct others on where to place and how to wire his equipment. A system allowing the client to transport and set up his own DJ equipment would afford him independence and empower him to take an active role in the set up process.

Methods

The Beatmobile is comprised of several main components, including the cart base, lighting system, trailer hitch, ramp and winch system, and electrical connections for the client’s DJ equipment.

The base of the cart is constructed from commercial metal shelving units and legs. Aluminum braces on the sides and back of the cart provide additional stability. The cart rolls on 3” diameter rubber caster wheels. Two of the four wheels feature a locking mechanism that act as a brake when the cart is stationary.

The top of the cart base is an extendable tabletop. This feature allows for additional legroom when the client is seated. A sheet of ABS plastic on the tabletop provides a smooth surface for the client’s laptop and mixing table. Wooden speaker pockets are mounted on the bottom of the cart base. They are bolted to the bottom of the cart using aluminum brackets. They are custom fitted to the speakers and prevent the speakers from moving during transport. The pockets are positioned so as to provide optimal sound quality when the speakers are in use.

Modular lighting poles support the lighting system. These hollow aluminum rods are lightweight and easily assembled. The top lighting pole inserts into the bottom pole and locks with a pin. The client’s lights are displayed on a lighting truss. Steel cylinders connect the truss to the lighting poles and prevent lateral movement of the truss. The truss can be raised and lowered by the client using a hand crank attached to the side of the cart. A pulley system raises the truss. When the truss is raised, the lights are displayed at a height of seven feet. A release mechanism allows the lighting truss to be lowered for disassembly.

A trailer hitch connects the cart to the client’s electric scooter, allowing the cart to be towed by the scooter to its desired destination. A bearing in the trailer hitch allows for lateral movement of the cart. The trailer bearing freely rotates around a pin and provides a wide turning radius for the cart. A small piece of HDPE prevents vertical movement of the bearing in case the cart is towed over rough surfaces. A pin connects the trailer bearing to the trailer coupler. The trailer coupler acts as an adaptor between the cart and the scooter. The adaptor is connected to the receiver hitch of the client’s scooter using a second pin.

The 7’ Trifold Advantage Series ramp is included with the Beatmobile. The cart is loaded and unloaded into the back of the vehicle using this ramp. The coarse surface prevents unwanted slippage of the cart. These attachments also ensure the ramp is secured in place when loading the cart. The ramp collapses for easy storage.

A winch provides assistance for loading and unloading the cart. The winch can be easily clipped to a hook mounted on the side of the cart. A remote control allows the user to control the retraction and extension of the winch cable. Tension must be applied at all times when operating the winch. The winch includes a free spooling mechanism that can be engaged by pulling the clutch out. This feature should be utilized if the cable is not in tension.

To improve the efficiency of set-up, cables for the DJ equipment are pre-wired into the base of the cart. These electrical connections reduce set-up time and provide a much cleaner, organized appearance. Two surge protectors provide electrical connections for all of the DJ equipment. All power cords connect to an extension cor reel on the base of the cart. The cost of the components for the device is approximately $430. Figure 2 shows the client using the BeatMobile.

Results

The BeatMobile supports the complete functionality of the client’s DJ equipment and eases the performance and set-up process. The client was very satisfied with the BeatMobile and plans to use the project at his next gig.  His mother, who previously loaded all of the equipment manually, agrees that it will significantly reduce her workload when setting up for shows. The client stated that he was “very excited to use the device,” and his mother said, “She is very grateful for the BeatMobile because she will not always be there to help her son set up for performances.”

Acknowledgements

We’d like to thank our client, Mike, and his parents for dedicating so much time to working with us. We’d also like to thank Ashley and the Bridge II Sports organization for accommodating our client meetings and testing. A huge thanks to Dr. Bohs for supporting us throughout this project and our TA Costi for helping overcome various challenges with our project.

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