Various designs have been explored to deal with the cable. The method should:

- Be able to roll up a 45cm long cable
- Have low learning curve
- BE self-explanatory
- Not block the user's grip
- NOT be the weakest link of the stylus (most important!)

And here are the major Pros and Cons of different designs:

Removable/replaceable cable - Pro: cable will never be the weakest link. Con: cable is not managed.

Spring equipped retractable system - Pro: simplest. Con: too much fun to play with, invites people to mess with it which leads product failure.

Cable wraps around the pen - Pro: easiest to manufacture, easy to perform. Con: looks amateur, blocks the grip when cable is NOT released.

Sept 2016 marks the turning point of SonarPen. I realize if the cable wraps around the top part of pen vertically, the design will look tidier than around the pen. It will meet the above requirements, and very easy to manufacture. Based on the same concept, a few more revisions with a different way to wrap were developed. The one that has the lowest learning curve and parts count made final.

Early prototype with retractable cable

In 1 and 2, cable is wrapped around the pen when it is not in use.
In 3, cable is rolling onto a wheel at the grip.

No moving part, low learning curve cable management system

The soft logo tag is doubled as a handle to release the cable.