Tetent TimerSpy [gd0136]

A wearable PDA / smartwatch with a Tetent [gd0090] input method.

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This is a wearable input device that uses Tetrinsics [gd0041] and reflective LCDs to run TaskPercent and Interval Provisional [gd0140][gd0097].

The size looks rather large (unless you're a 3D game character like Dr Eggman), but how else am I supposed to (hypothetically) type over 150wpm and mouse through menus on a wearable?

Like Tetent, I hope to use 2 TimerSpys (TimerSpies?) at the same time.


The title tag system is explained here, and the table is updated when a change occurs. Notable logs have bold L# text.

[R] Screen Options
[M][T][R] Side profile sketch
[T] 3.5" Screen PPI
[M] 1st Concept
[T] UI with Tetent
[M] 90*60*60mm package?
[M] Concept with LCD buttons
[P] 2nd Concept
[T] Thoughts after spending more time with the print
[M] Left Arm Section
[M] Concept with haptic feedback switches
[M] Concept tweaks and added detail
[M] Thumb button and logo
[M] New, sharp concept
[R] Other wearable computers
[P] The new concept
[M] Tetrinsic realignment
[P][M] Attempt2 and 3
[P][M] Attempt4
[M] Attempt5
[M] Attempt 6 - 7.1
[P][M] Attempt7.2 - 8 and magnetic straps
- Concept print finally feels good on arm
[T] Use CM4 for its MIPI DSI feature?
[R] The ANX7688 USB-C Alt Mode Chip
[M] Moving screen up
[M] Incorporating Tetrinsic 2.0
[R] Polymer battery search
[A] Name change: "Timer Spy"
[M] Finger5 Side Design
[M] Buildable created
[T] Concept Attempt9
[M] Attempt9.1 Design
[M] Design tweaks
[M] Sliced front screen texture
[T] Concept Attempt9.1... fails.
[T] Dorsal mounted solution
- a.k.a. mounted on the back of the hand
[M] Battery pack
[R] Parts to be used
[T] Low-power computing
[T] Mounting, power and sound concerns
[M] Battery fits beautifully
[P] Designed basic concept
- Concept that mounts to the back of the hand
[A] Details page before 13 Jan 2024


[2022 - July 8]

I got my new Android 8.1 smartwatch a few weeks ago, called the i3 AMOLED.

It's the first AMOLED watch I've owned, and probably the 11th or 12th full-android watch. It looks nice and has a comfortable strap and the AMOLED display means that I can have an always-on-display app. This watch seems to have come out very recently (March 2022 maybe) and so I'm not expecting any manufacturer to come out with a fancy new chinese smartwatch for another year or two.

It still lacks in the areas I expected it to: battery life, UI control and screen angle (the screen naturally wants to face away from my face, as with all traditional watches), and this project looks to see if I can design a new smatwatch with these features. 

I imagine success / failure of the project relies on #SecSavr Suspense [gd0105], but moreso on a Tetrinsic that physically works.

  • [A] Details page before 13 Jan 2024

    kelvinA01/13/2024 at 14:29 0 comments

    Notable Tetent projects, sorted by project log count:

    [1 Jan 2023]

    This is the project that aims to deliver the wearable version of #Tetent [gd0090], which --in an ideal world -- would be the only required version. Unlike most input methods that rely on buttons, Tetent's keymap layout require #Tetrinsic's [gd0041].

    [8 July 2022]

    I got my new Android 8.1 smatwatch a few weeks ago, called the i3 AMOLED.

    It's the first AMOLED watch I've owned, and probably the 11th or 12th full-android watch. It looks nice and has a comfortable strap and the AMOLED display means that I can have an always-on-display app. This watch seems to have come out very recently (March 2022 maybe) and so I'm not expecting any manufacturer to come out with a fancy new chinese smartwatch for another year or two.

    It still lacks in the areas I expected it to: battery life, UI control and screen angle (the screen naturally wants to face away from my face, as with all traditional watches), and this project looks to see if I can design a new smatwatch with these features. 

    I imagine success / failure of the project relies on #SecSavr Suspense [gd0105], but moreso on a Tetrinsic that physically works.

  • [P] Designed basic concept

    kelvinA02/20/2023 at 20:10 0 comments

    I've designed and printed 2 concepts. The first one was a general shape and the second one (pictured above) was moving the Finger5-to-Finger4 offset from 26mm to 21mm, adding a screen I just found and changing the back angle slope for better ergonomics.

    First version:

    The LPM013M126 screen I found:

    This screen is rather nice because it's reflective and backlit and doesn't cost £50. I was going to try and use a 21700 when I reduced the Tetrinsic offset, but this screen would only barely fit with the 26650.

    The second attempt:

    The sceen is on the most ergonomic face, so I'm thinking of skipping the 2.7" screen either altogether or until I've got a working prototype and feel that I could use a larger screen.

    I'm also thinking of designing the rear-hand mount such that a pocket (shown in purple) could slide inbetween the hand (brown) and the TimerSpy (grey):

    That way, it shouldn't get in the way when putting my hands in pockets while still being able to slide through a sleeve.

  • [M] Battery fits beautifully

    kelvinA02/20/2023 at 01:07 0 comments

    I looked around on AliExpress to get an idea of the available batteries and their properties (capacity, discharge and dimensions) and they seem really good. It seems easy to get a reputable 5Ah battery and they all have high discharge currents (>10A continuous) that the BLDC motors can make use of. One of the physically largest ones I could find had a diameter of 26.8mm and a length of 65.2mm, so I'll model a D27 x 66mm cylinder.

    Not quite sure if a 5.5Ah cell is actually possible, but perhaps 5.1Ah. This battery is notably pricier than the 5Ah ones though.

    Those discharge currents are also a bit worrying. I really don't want a short, because these batteries are capable of discharging like 70W continuously. At that capacity, I might consider going with a non-removeable setup (a 26650 with prefixed wires) but I'd still like removable ones if possible (it's one of the stretch-goal requirements).

    Wouhh!! That's a first. Underpromising in this Aliexpress battery industry? The listing claims 5Ah but reviews are coming in and they're all >5.35Ah. Keep the current draw low and over the 5.5Ah boundary is possible.

    Anyway, I had modelled in the battery and... wow:

    It just perfectly slots in. I can't believe it. I was losing hope that a solution could exist but a path forward is right here that can still deliver on my desired requirements!

  • [T] Mounting, power and sound concerns

    kelvinA02/19/2023 at 20:59 0 comments

    So I streamlined the Tetrinsic concept in an effort to give the TimerSpy the best chance of success. There's still an issue that I've just glossed over this entire time: hand mounting. 

    It seems that an ergonomic solution is one where the Tetrinsics are, at most, 90 degrees from the fingers if the hand was flat. I think the minimum bound is somewhere around 30-45 degrees. However, the most ergonomic orientation of the screen is perpendicular to that (so parallel with the side of the hand where the thumb is). The second most ergonomic is on the back side of the Tetrinsics, which seems to be a straightforward location to mount the screen. 

    Since both #TaskPercent [gd0140] and #Interval Provisional [gd0097] use colour to convey information quickly, I don't know of any >=600 nits screens (let alone a 3"-ish one), I'm trying to keep things low-power and the backside of Tetrinsic needs to be smooth (so I can't mount a frontlight overtop), it seems that I've got a simple yet inescapable choice and I'd have to use the rather expensive 2.7" reflective colour LCD.

    Back to the mounting situation, I can only imagine a solution that is similar to "gest":Gest | Wearable brings interaction to a whole new level. Use just your ...

    The issue I've been having for the past 5 days is that:

    • I need to fit in a battery and speaker somewhere. 
      • It's likely going to be a 18650 but I'm looking more towards a 5Ah 26650. 
      • It doesn't seem like there's any good off-the-shelf phone speakers that... probably sound better than generic phone speakers. I'm considering going with a smaller battery just so that I can have a speaker with more low-frequency response to improve my Interval Provisional experience (I want to use low-frequency sound effects for a calm/focused feel).
    • I'm trying to keep the width of the TimerSpy under the width of the hand so that I can still rest [the side opposite the side of my hand with the thumb] on objects. However, for a gest-like mount, it would need to be wider than the hand so that it could wrap around it.
    • The fingers will exert a significant moment about the palm of my hand. This means that magnetic solutions are unlikely to work.

    The Tactigon Skin is a potential mounting method whereby I can put the battery and/or speaker on the rear side:Gesture Controlled Home Automation with Raspberry Pi - The TactigonI'm considering using the 80x15mm samsung tv speaker I found for TyMist on the back and a 26650 under the Finger2-4 Tetrinsics:

    At the end of the day, the human->computer and computer->human pipeline/interface is the most important pipeline/interface of most of my projects. This specific project is essentially the equivalent of PC RAM for people (where short term memory is cache and long term might as well be eMMC) so I've got to really make sure it's done well and that means that audio quality should be at a similar calibre of consideration as Tetrinsic, not a painful afterthought like in so many portable devices of the last decade. Turns out just under 80% of survey respondents say that good phone speakers are important. A solution might have an Alienware / OneNetbook GX1 look to it, where that back grill is the speaker:

    OneGX Preview and pricing : onegxThe resultant TimerSpy might not be able to slide into a pocket but it'll still look aerodynamic.

  • [T] Low-power computing

    kelvinA02/14/2023 at 21:23 0 comments

    I've been thinking, and have come to the conclusion that TimerSpy only needs to do 3 things well, software wise:

    1. Tell the time
    2. Run #TaskPercent [gd0140] 
    3. Run #Interval Provisional [gd0097] 

    And ideally run #enSweepen [gd0096] and Visual Studio (Code), but that's of lesser importance. Essentially, it's the kind of applications that would run on a 1990/2000s PDA. I need some wireless connectivity like WiFi or BlueTooth for synchronisation, but I shouldn't need the power of a CB1 or CM4 to run those 3 main applications.

    Along with a microcontroller, I was thinking of using the frontlit 3.2" memory LCD from Digikey but that was out of stock. There are £42 frontlit 2.7" ones, but AliExpress has a nonlit version for £17. I think I can just add some LEDs on each side, and could potentially look cooler than the frontlit version.

    With the main requirements in mind, I'm thinking of trying to have everything, including the battery, fit on the back of my hand. I still haven't come up with a solution that allows for a Thumb1 Tetrinsic, nor do I have a mounting solution, so I'm going to allow for a solution that uses the thumb to hold TimerSpy in place.

  • [R] Parts to be used

    kelvinA01/02/2023 at 22:43 0 comments

    Hand mount strap

    I found...

    GoPro mount gloves like this:

    Self heating ones like this:

    Flashlight holding ones like this:

    And a quick release one:

    Always-on display

    I think, for design consistency, I should go with a square display:

    There is also the idea of going with a long, rectangular one so that the screen could be angled towards my eyes (if the square one would stick out too far):
    I also discovered that there's apparently a colour memory LCD in existance and it's not even that expensive, so I'm most likely going to go with this:

    Main square display

    To share parts and research with #T^2 TyMist [gd0138], I think that using the same square screen is the best choice. This could actually be like a project collab with myself, where I can skip past the expensive, off-the-shelf control board for TyMist because I made a custom one for TimerSpy.

    This screen can go up to 120Hz and has 300 nits of brightness. There is also a much cheaper alternative version that only has 150 nits, but that's because it was tested has a 10% backlight duty cycle (something done to reduce motion blur in VR)

    Solution mining... ends, in 29 days.

  • [M] Battery pack

    kelvinA01/01/2023 at 23:34 0 comments

    My original idea was to have 4 white diamond extrusion and the battery + CB1 would be in the green section underneath. I thought the height of the 4 diamonds might be too much of a waste, so increased it to 5 so that the sizes (and hence the height) of the diamonds were smaller.

    I still wasn't expecting it to be so long. It's 116mm right now. I also thought that it was a bit of a height waste, and moved the CB1 into the diamond section:
    The width is also wider than I'd like, but I really should just play it safe for now and go with the highest battery capacity that should theoretically work.

    I'd like to add a slight tilt to the faces of the diamond extrusions (like seen in the previous attempt) but I don't think I'd really have the space.

    Solution mining... ends, in 30 days.

  • [T] Dorsal mounted solution

    kelvinA01/01/2023 at 18:04 0 comments

    I just found out that the back of the hand is called the "dorsal side of the hand". Why nothing simple like with "palm"? Well, in a search of a solution, I ruled out a VR glove style solution since I still need my hands to fit in pockets and the pushing force of the fingers is unlikely to be at the fingertips. The back of the hand (for which English still hasn't given a shorter name, like dors or something, though dorsum is probably good enough) is still free real estate. 

    As I'll soon write in a #Tetrinsic [gd0041] log, my fingers demand a solution even thinner than 16mm. At the moment, it's feeling like under 6mm. I've got a solution in mind for that, but I also wanted something that addressed the other issues I've run into in the recent TimerSpy concepts, such as:

    • Sleeve either needs to be out of the way or the device needs to be over it to use it, especially if I go down the vertical Tetrinsics route.
    • The thumb isn't doing anything, thus bandwidth is being left on the table.
    • Both arms have to be coupled together, reducing usefullness and ergonomics.
    • Both arms can't be typing at the same time, unless on a desktop.
    • The desktop ergonomics are poor and I'd probably only use it for 60 seconds.
    • The screen makes it harder to put my hands in my pockets.

    However, I don't want to give up that 10Ah battery I sourced (every other seller said no btw), and the 10Ah seller said that the size is 7.2x70x98mm). That's 37Wh. I'm finding 13" laptops and tablets with that kind of battery capacity!

    The idea is to mount the devices on the back of the left hand and then the right hand slides in to eject it from the left and mount it under the right hand fingers (opposite hand roles for the other TimeSpy being worn). On these new TimerSpies, a smaller, likely MemoryLCD display is used for time tracking and the OLED, which is against the back of the hand, will be the main display. It would be infront of the palm when in use. It might be on a hinge to reorientate it to a more ideal angle, but I think the palm is ergonomic enough for now. I could probably also use an LCD for this, such as the cheaper 2.9" 120Hz 1440px one I found for #T^2 TyMist [gd0138], since the smaller screen would be the always-on display. If anything, sharing components like that could speed up overal project development because I really do need these things and I needed them 5 years ago.

    In other news, I'm also going to be looking for another strap solution. The magnetic chainmail slowly loosens over time during use, and the magnet makes it hard ot put the TimerSpy on as it makes the whole chain stick to itself.

  • [T] Concept Attempt9.1... fails.

    kelvinA12/30/2022 at 20:50 0 comments

    "Please tell me the solution passes-- the solution fails."

    Finger5 is saddeningly short -- so short that it sometimes feels like it actually hasn't grown fully or like it's an extra digit that was there from birth.

    Unfortunately, since my arm is in the way, I don't think I could get a solution for using the thumb either.

    I was like "How was Concept A8 doing things?" and put it on, and now even that feels misaligned. Perhaps I just hoped it'll be an issue that slowly goes unnoticed, but the angle I need means that the screen is pointing near-45 degrees off axis to my eyes:

    This, but with Concept Attempt8

    Then I noticed that Tetrinsic 1.0 was much closer to the edge than now:

    Oh and basically none of the 3 main fingers actually align. The 3.25mm drop on Finger4 is significant, and the distance between Finger2 and 3 can't seem to mesh, even though I brought them closer for that reason. Now they want to be further apart.

    I think the complex but seemingly inescapable choice would be to actually have the Tetrinsics on a hinge that rotates 45 degrees such that the thumb can hold the hand and provide stability and the fingers can still reach the Tetrinsics:

    At least the 93mm length and trimmed down green section make the device look more compact. I'd still likely go with the 98mm for that 10Ah (or maybe even 11.6/12Ah) battery. Obviously, being ergonomically viable is more important though.

    Actually, trying literal air, it looks like Finger5 either takes an unobtainium 3mm Tetrinsic, or a normal Tetrinsic at a 90 degree vertical (starting from the arm). It all makes sense now that I actually have an ergonomic location for the thumb. However, thinking up a solution that actually does that is very non-obvious. Maybe I've got to give Tetrinsic Gloves another thought?

  • [M] Sliced front screen texture

    kelvinA12/30/2022 at 16:44 0 comments

    Whilst also trying to diagnose my DP2 FFF printer, I finally tried something I thought could work better than having an air gap for the front decal. I exported a second STL and was easily able to merge the bodies and change the relevant settings to get the effect I wanted:

    It's printing now and perhaps I should've gone with dual thick infill so that the lines didn't cross over each other. It all seems to be sticking fine (and going much faster than dual lines since the printer decelerates much less often) so I'll leave it.

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