Designers: Michael Cote, Thomas Musgrave and Andrew Schmidt
Client Coordinator: Lorie Martin
Supervising Professors: Richard Goldberg, Kevin Caves
INTRODUCTION
Our client is an eight year-old boy with cerebral palsy and autism who, due to a recent surgery to his leg, spends little time voluntarily walking. The aim of this project is to build a device that would use music to stimulate the client to walk on his own. The Walking Motivator includes a pedometer to detect motion, a microprocessor, an MP3 music player, and headphones. Other than the headphones, the entire device fits inside a small pouch that straps onto the client’s hip. As long as the client walks, the music plays; when he stops, he receives a message to motivate him to keep walking. The device is very effective for stimulating the client to walk.
SUMMARY OF IMPACT
During testing of the device at the client’s school, the client seemed to recognize that something unique was occurring, as he would stop and think when the music would stop or start playing. After several minutes of successful testing with the client, his teacher stated that it would allow him to “focus on walking more than music” and that it would help “eliminate lazinessnot make you work to make me walk.” The client seemed upset when the device was taken away from him, a good sign. Finally, his therapist was pleased that the Walking Motivator’s most efficient operation was when steady steps were continuously taken, something that the therapist has been working towards with the client. With help from his teachers and therapists to successfully integrate its use into his classroom activities, and perhaps eventually his parents for use at home, the client will build leg strength, gain more comfort in walking, and be more self-reliant for traversing longer distances.
TECHNICAL DESCRIPTION
The Walking Motivator (Figure 1) is a motion-activated music-player, containing a pedometer, a PIC microcontroller and an MP3 player. A commercial pedometer (Digiwalker SW 701, Yamax Corp, Tokyo) contains a switch, which closes and opens each time the user takes a step. The pedometer was modified to disable all features other than this switch. Wires from the switch are connected to a PIC microprocessor (16F876, Microchip Corp, Chandler AZ) in such a way that each step produces a low pulse (5V to zero). Software in the processor continuously monitors this signal, interpreting each low pulse as a step. When the software first detects a step, it triggers an MP3 player (Rouge Robotics, Toronto) to start playing music as a reward.
When the PIC detects walking motion, the music is played continually until no walking motion is detected for six seconds. After six seconds, the music is stopped and a motivational cue is played which explains that music will start again if the user starts to walk again. The PIC program contains a filter to guard against false positive detections of walking. This filter determines the frequency of steps, and if it is too high, triggers a different message to that informs the user that the device will not play music unless normal walking is resumed. Additionally, if the PIC detects no walking motion for six seconds, it powers itself down to a sleep mode to conserve battery power.
Music was collected from the client’s teacher and uploaded to a Flash memory card, which plugs into the MP3 player. 91 songs are stored on the card.
The pedometer, PIC, and MP3 player are packaged in an 3-1/4″W x 4-1/2″D x 1-1/2″H ABS plastic project box, which contains an easily accessible 9V battery holder. A voltage regular drops the voltage to 5V for the microprocessor. Headphone wires exit the box and connect to standard audio headphones.
The device is worn on the hip of the client to allow for maximum efficiency of walking detection. The project box must be oriented properly for the pedometer to work reliably. This is ensured by attaching the device inside a camera case, which has been connected to a luggage strap, and strapping this ensemble around the waist of the client.
Cost of parts for the device was approximately $390.