Achilleas's Take on Christos's Prototype

Since the prototype was posted yesterday I have revised some of the details and more clearly defined some other points. Additionally I would like to talk about the design of the pen in more detail and added to the prototype some elements that were left out.

First of all, Christos neglected to specify the power source for the pen. This particular part is quite tricky since it can't be too large as it will affect the size, style and weight of the pen since batteries and battery packs tend to be quite heavy and bulky. On the other hand it must be large enough to power the pen for a substantial amount of time.
I considered using a single standard AAA battery first. This idea was dismissed however since we figured a single battery of that size does not have the capacity or the power output we need.
My second consideration was using several LR-type "watch batteries".
I also considered using a built in battery pack with a plug-in charger or a removable proprietary rechargeable battery, that would be charged using an external charger provided with the product.
It was decided that the final idea was the best. Building a proprietary battery makes it easier for us to give the power output we need for the specific application but having it build in and using a plug-in charger would mean we would have to include a plug on the pen, which results in adding more components.

The position of the battery on the pen is another issue we needed to deal with. For obvious reasons the battery should be as low as possible. The heaviest components should be low while the lightest should be high, at the top of the pen, to make it easier to write with. So the battery will be placed directly above the ink container, simply because the ink container should be directly above the writing tip.

There is also an alternative option for the motion sensor. Instead of using a separate motion sensor at the top of the pen we could use a ball point style tip for the pen to write and use the ball movements to track the pen motion. This may result in even less components which would mean a simpler internal design to work around and less weight.

The single button functionality, as defined earlier, seemed a bit complicated. The goal was to have one button alone in order to keep the use of the pen as simple as possible but in order to do this with one button ti must be able to accommodate all the functionality of the pen in a very smart way. It may be simpler to add a second button. The first would be a big button that has two functions. It would turn the pen on or off when held for several seconds. The second function should be to reset the pen to entry mode when it is pressed and released instantly for the user to speak a word instead of turning the pen on and off when the in the middle of another word. The second button should be a button or a switch which selects one of the two modes available: Beginner and Advanced. Beginner mode is the learning mode which spells out the word letter by letter when the user writes while advanced mode simply waits for the user to finish writing the spoken word and at the end informs the user whether it was correct or not.

The pen functionality was also more clearly defined in steps:

Step 1: When turned on the pen should be in this step. This is a standby phase where the system awaits user input in the form of a spoken word. When the user speaks a word proceed to Step 2.

Step 2: Word identification. The system looks up the spoken word in the dictionary. If the word hasn't been recognized display a relevant message on the LCD screen, speak an easy to understand error message and return to Step 1. If the word is found, speak the whole word to signify that it has been identified and then proceed to Step 3 if in beginner mode or Step 4 if in advanced mode.

Step 3: Word spelling. Speak the first/next letter (maybe outputting it on the screen as well) and proceed to Step 4.

Step 4: User writing. User attempts to write the letter spoken for beginner mode or the whole word for advanced mode.
Beginner mode: If the letter is written correctly go to Step 3 with the next letter or Step 5 if it is the last letter. If it is written incorrectly, speak a relevant message such as "Wrong. Try again." and go to Step 3 with the same letter.
Advanced mode: Wait for user to finish writing*. If input is correct got o Step 5. If it is incorrect speak the "Try again" message and wait for input.

Step 5: Congratulate the user for spelling the word correctly and start over from Step 1.

If the reset button is pressed during any part of the process the system should return to Step 1.

Notes:
*The end of a letter can be recognized by a long pause in writing or a specific pen gesture such as writing a full stop or a straight horizontal line. Ideally it should be something that cannot be confused with anything else. A full stop may be confused with dotting i's for instance and a line may be confused with crossing a t. The long pause seems to be the best solution here.