Electronic Product Design: Final Report

portaMid: A Miniature Bluetooth MIDI Keyboard

The portaMid keyboard is a MIDI keyboard that works over the Bluetooth Low Energy (BLE) protocol which allows one to control music apps on any Apple iOS device. The device contains a 500 mAh lithium polymer rechargeable battery which lasts for many hours of use.

The one octave of piano style keys are soft to the touch but contain tactile feedback so that the user knows when the key has been pressed. Utilizing the octave keys, the user may lower or raise the octave in which the piano-style keys play. The LED represents the octave selection via different color output.

A removable phone mount allows for use on the go for different sizes of iPhone. In fact, every iPhone since the 4S is supported by the device. Most music apps support MIDI over BLE natively and connect to the portaMid with no configuration required: just connect and use. An example of set-up with the GarageBand app may be found in the user manual.

User Feedback

For testing, the portaMid was given to two people for a week each. The following is the feedback from the first person:

I love the PortaMid!! As a musician who uses midi for all of my projects, it’s so convenient to be able to have an external midi controller. Especially because it’s so portable! I can easily fit it into my purse or backpack and use it wherever I go, train, bus, or at home. I also really love the design, the PortaMid looks as fun as it is to use. The buttons are accessible and labeled to help easily find the functions. I can’t wait to have a PortaMid of my own!

The second person had the following to say:

Positive Reactions!

• Good size to hold

• Clear and simple user manual

• LOVE the color change for different octaves- that was very useful

• Bluetooth easy to set up

• It only took me 10-15 min to get the hang of it and start playing melodies.

• I was really excited about the product, and it was more fun to use than I thought it would be

Thoughts or Critiques

• My phone would weigh down the stand and end up laying out horizontally. (I tended to use portaMid horizontally on my lap anyway)

• It would be nice to have a battery indicator so I knew how much charge it had left.

• I plugged it in to charge and naturally expected the light to show that it was charging. After reading the manual, I still expected the STATUS light to turn amber, and got confused. I re-read and realized that a light by the connector delineates that the device is charging

• I love click-y buttons, but it was difficult to push them down (at least if you wanted to try and play a chord)

• It may be easier to use if it looked more like a piano in some way- so by brain would not take as long to think of where a particular note is

• The ‘porta’ part in the name almost reminds me of porta potty. But of course it gets across what it is and comes with an awesome logo

• Thank you for letting me test it!

Improvements & Future Work

Going forward, further refinements to the device will be made. For example, it would be nice to have buttons that have the tactile feeling but are less difficult to press and create less noise. Research needs to be done on what could replace the standard tactile buttons with something that is better. In addition, it would be nice to have some velocity sensitive keys for playing more than one dynamic.

In addition, I will need to create a circuit that can poll the battery level at intervals in order to indicate the current charge level or if the battery is dying.

The stand could use a wing-nut to allow the user to adjust the tension so as to keep the unit in the proper position when in use. Also, it would allow for ease of removing the stand entirely.

While using the product, I found myself gripping the device like a game-pad. I had the thought of incorporating shoulder buttons which could be used for modulation, pitch bend, after-touch pressure, etc.

I envision an entire line of these being made with different properties. For example it would be nice to have a version that mimics the Moog style ribbons, or another version that is a mini sequencer. It would only take finding different sensors or button layouts and incorporating them into the current design for a completely different type of interface.