The technology to make this a reality could be invented within 50 years.
Today’s fitness trackers range from $50-250 in three main form factors: bracelets, clip-ons, and watches. Some track sleep, and some are sport specific. Because these devices are made to be convenient to wear when working out, they require a companion app on a cellphone or desktop to view advanced data metrics.
All of them are battery operated which means they need to be recharged every night or can run up to a few weeks, but need the battery changed after that.
1sp (skin pixel) = 0.25mm = 0.94px = 0.71pt
Smallest average forearm size: 220 x 70mm = 880 x 280sp
Thinnest tattoo needle: #6 needle at 0.20mm = 0.8sp
Minimum line weight: 0.25mm = 1sp
Minimum type size: 3.53mm = 10pt = 14sp
Touch target size: 7-10mm = 28-40sp
Information zones: Least important to most important
Responsive mode: Horizontal to vertical, inside to outside
Alternate display: Outside wrist, hand
Alternate interactions: Gesture based
Skin color: All supported
Atmel® ATBTLC1000-MR110CA Bluetooth Low Energy module
- $11 per unit (low volume)
- 2 × 2mm
- 1.8 – 4.3V
Quallion QL0003I Li-ion cell
- 2.9 x 11.8mm
- 3mAh at 3.6V
- Extended cycle life
E-ink two-pigment subdermal display
My sketches helped visualize where on the arm the tattoo would be best located for easy interaction and visibility. I also explored some gestured-based controls for hands-free interaction.
1) Close apps; 2) App icons
Options: Power off, move up/down, lock position
1) See and move target heart range; 2) Current BPM
1) Responsive graph minimizes to the side; 2) Warning appears with explanation
1) Stopwatch currently selected; 2) Watch is paused
1) When the watch is active, the menu decreases in size to call less attention; 2) Split times scroll up the arm as added
1) Drag up or down to change the time; 2) Start timer when ready
1) Timer is active
1) Controls in the middle; 2) Music visualization is cool to look at, but not distracting; 3) Current track information