Thinking about Kids

I thought some more about the LogStick today and thought about the user base—kids!
Hmmm…Not the most patient, careful or sometimes willing users of technology. I sat down and came up with the following set of product requirements:

Key Product Requirements

Simplicity
A child of 9 should be able to use this:

• Easy to handle—like a stick
• Easy to connect—use USB (not MMC cards, not Ethernet)
• 2-button input interface
• Sensors automatically register themselves
• Audio output interface (beeps, bings, boings, etc.) with additional pulsing LED (used in noisy environments or when battery is low)
• Simple 8-segment green, yellow, red representing state of collection: red = no data yet, yellow = reasonable dataset, green = good dataset OR green = buffer empty, yellow = reasonable dataset, red = buffer full (need to decide!)

Instant Gratification
A child of 9 should enjoy using this:

• Simple setup in classroom before children deploy device (may be done by teacher or by children).
• Lots of audio/visual feedback (beeps, bings, boings, computer voices, etc.) with additional pulsing LED (used in noisy environments or when battery low)
• Connect and Display Results! Connect via USB that automatically invokes graphing package on the PC to show results of logging—immediately!
• Running out of power is a major turn-off

Ruggedness
Children between 9 and 14 will use this again and again:

• Drop from > 3 feet and still works
• No parts to break off
• Easy to manipulate with small hands
• Hard to get into! (Even a destructive 11 year old with a multi-tool would find it hard to break it) Easy to add logging sensors in the field
• Rechargeable or uses basic 9 Volt battery. (Could save state during battery replacement, which could potentially lead students to “tend the garden”—replace the battery in situ.) Or is rechargeable using USB (overnight is ok)
• Waterproof or at least drip proof.

Battery Life
Needs to run for over 1 week on a battery charge or on a standard 9V battery. Experiments are unlikely to exceed one week.

• Lesson 1: deploy LogStick in the field.
• Lesson 2: recover LogStick from the field and immediately graph results.

Price
School equipment either needs to be really cheap or subsidized. If not subsidized, the cost should be in the low 10’s of $.

Note: USB memory sticks with ARM processors in them (I think) are really cheap now.

In my next entry, I’ll figure out which MCU to use.