News from the PocketPro Team: PocketPro and SkyGolf Join Forces. Learn more here or check out the new site at golfskypro.com

How it Works

PocketPro's hardware has three primary responsibilities. It is able to capture a golf swing's motion, save this data to memory, and wirelessly transmit saved swings to another device. Currently it uses a three-axis accelerometer and gyroscope to capture swing motion and a single chip Bluetooth solution with PCB antenna to transmit data to an iPhone or computer.

Accelerometers / Gyros

MEMS accelerometers and gyroscopes are now fairly common, but finding sensors with a suitable range for a golf swing was difficult. Our accelerometers and gyroscopes are able to measure ±19 G's and ±2000°/s respectively. In addition to a large range, they also have a high level of accuracy, maintain a fast sampling rate, and draw minimal power.

Antenna

Another important aspect of our board layout is the on-chip antenna. Our design includes a microstrip line etched into the PCB, which provides an extremely small, and very effective antenna. Our current Bluetooth range is 40-50 feet.

Software

PocketPro's software is responsible for converting the raw motion data from the sensors into a golf swing, and then analyzing and displaying the resulting information. It can render the complete motion of the club in 3D, and display parameters such as swing speed, face angle, and club path with a high degree of accuracy. Although currently developed for iOS devices such as the iPhone, iPad, and iPod touch, the majority of PocketPro's software was designed to be portable to other platforms.

OpenGL Club Torque View

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In the club torque view we are able to graphically display the deflection of the golf club head during the swing - i.e. the distance from the clubhead to where it would be if the shaft wasn't bent.  To a close approximation, this distance should be proportional to the torque the hands exert on the club.  Therefore, the units displayed at the upper right are units of torque (Nm).  Also, the frequency that we can measure is the resonant frequency that the club would vibrate at if you clamped the grip in a vice and struck the club head.

OpenGL Swing Impact View

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In this view we are given a close up of the club head at impact. With the position of impact as the pivot point we are able to move in full three dimensional space while the swing plays. From here we can see the attack angle represented as well as the path angle. The colored lines help us see how the golfer's swing path approaches, contacts and follows through the ball.

OpenGL Swing Path View

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In this broader view we can see the overall path of the golfer's swing. Again, we are given full freedom to zoom and roate around the golfer. Playback of the swing can be done at full-speed or scrubbed through for specific areas of swing anaylsis. There is a slide up drawer on the bottom which displays the club head speed, impact angle, as well as a velocity vs. time graph of the swing.




Measured and Calculated Swing Parameters

By measuring the acceleration and rotation rate of a golf club at any point in time, we are able to measure or calculate the following points of interest:

Directly Measurable

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Tempo
Measure essential timing parameters of a golf swing, and display any extreme values of acceleration to highlight "jerky" areas.

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Release Factor:
PocketPro is able to accurately measure the precise time when the wrist angle is released during the downswing.

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Angular Velocity:
PocketPro is able to accurately measure the full rotation rate of the golferʼs hands throughout the swing.

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Swing Plane:
Measure the angle made between the ground and the plane of club head trajectory at the bottom of the swing arc.

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Swing Direction:
From our data PocketPro can measure the horizontal direction the club head is traveling in at the bottom of the swing arc.

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Transition:
PocketPro can measure the duration of the transition between backswing and downswing.


Calculable

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Swing Velocity:
From our captured data PocketPro can calculate all components of the club head velocity at any time during a swing.

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Swing Path:
Once data is captured PocketPro can calculate the club head position at any time during a golf swing.

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Dynamic Face, Loft and Lie Angles:
Given a full swing of captured data PocketPro can calculate how the face, loft, and lie angles have changed from their values at address

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Angle of Attack and Club Head Path:
Calculate the vertical and horizontal angles between the target line and the path of the club head at impact

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Launch Direction and Angle:
Calculate the initial direction of the ball relative to the target line, and its vertical angle off the ground.

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Clubhead Deflection:
Calculate how much a club bends during a swing based on the data from the sensors and physical properties of the club