Machine Design

Inventor's corner: App helps kids fight leukemia

Inventor’s Corner usually showcases “midnight engineers” — the inventors who come up with patentable ideas in their spare time, off the clock. Here, we are doing something a little different in featuring someone who has created a few iPhone apps. Typically, iPhone apps would be outside of the normal scope of this section, but the “inventor” is a high-school student and we felt that his products deserved a little exposure.

Billy Barbaro, a junior at Carroll High School, Dayton, Ohio, created apps called SceneTimer, TakeTimer, ShowTimer, and Pediacenter. The first three are for TV and radio production, with SceneTimer and TakeTimer available on iTunes. According to Barbaro, ShowTimer is in the approval process and will hopefully join the other two shortly. For more information, see

Barbaro is currently developing Pediacenter and says it is the most ambitious project he has undertaken yet. The application was inspired by his three-year-old cousin who was diagnosed with leukemia along with the fact his physics class required him to enter the science fair and he was looking for a suitable project.

As a result of medical treatment, his cousin needs to regularly monitor his vital signs. For example, he must take his temperature every 4 hr to make sure he doesn’t have a fever. Pediacenter provides an entertaining and efficient way to handle this task. It graphs patient temperature, date, and time, and also logs the data in a chart. The app provides quick and easy access to the patient’s doctor and also displays hospitals near the user with contact information and directions.

The biggest challenge in this project was building the hardware, says Barbaro. The first hurdle was setting up an interface to get data into the iPhone. The original design was to use either the iPhone’s 30-pin connector or Bluetooth. Both are sanctioned by Apple’s Made for iPhone (MFi) Program. But Barbaro ran into some trouble trying to join the program, so he looked for an alternative route. The only other port on the iPhone is the headphone device.

“I came across a technique called frequency- shift keying (FSK),” says Barbaro. “It’s what fax machines used with all the beeping and noises they made. “In a nutshell, it’s turning data into sound then changing it back on the other end. The digital values of 0’s and 1’s are modulated into sound waves of low (the 0’s) and high (1’s) frequencies. The resulting wave is sent through the headphone jack and demodulated using libraries on the iPhone side. This project relies on a HiJack board made by Project HiJack, found online at SEEED Studio.” The board is used to modulate the data received from the thermistor (or whatever input you attach to it) into sound and send it to the iPhone.

Barbaro then placed a thermistor in a voltage divider circuit and attached it to the board. The analog value is transmitted using FSK to the iPhone. The resistance value gets plugged into the Steinhart-Hart equation to calculate the temperature, which is then used throughout the application. The application lets the child (or adult) play computer games while taking his or her temperature. It will also call the doctor if the temperature exceeds a parameter set by the doctor or parent.

On the software side, Barbaro wrote all the code in Xcode and tested it on an iPhone.

The current version of Pediacenter ended up winning the county science fair. As a reward, Barbaro was invited to present at the International Science and Engineering Fair in May and competed against other student science projects from 65 countries.

Contact Barbaro at: [email protected].

Are you (or do you know) a “midnight engineer” who would like to get his or her product showcased in MACHINE DESIGN magazine? Please contact Leslie Gordon: [email protected], (216) 931-9242

© 2012 Penton Media, Inc.

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