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• [R][T] Slide-out screen shortlist: Blanview 3.5" or Transmissive 3.4"

  kelvinA • 2 days ago • 0 comments

  Screen shortlist

  I tried to find some options that could fit on the side of Tetent (like many of the past concepts) but it makes little sense from both an ergonomics and bundle adjustment perspective.

  I'm going to be designing a square GUI for a better Tetinerary solution, and that allows for these options:

  Coming in at the same price as the first transflective screen, but without the £7 delivery charge, the 3.5in Blanview is the best available in LCD technology, featuring all the benefits and little of the drawbacks:

  Looking at the top graph, it seems that the backlight uses 40mW in bright ambient lighting conditions. In stark contrast, the transmissive, 1000 nits 480x480 panel (KD034WXFPD002) uses 768mW and the transflective 480x640 panel (FS035VG083-C035A) uses 372mW. Both these values are right on point to what the graph shows.

  One of the benefits of the 480x480 is that the GUI would look slightly larger, and that 2 panels is the same price as a single Blanview panel. However, as mentioned in the Bundle Adjustment log, I could develop with the entire 640x400 resolution found in the prism with the Blanview.

  Considering that my (not so temporary) "temporary" keyboard has now been in use for about 3 years, I think it's in my best interest to just go with the better panel upfront.

  Slide out screen?

  So this is all well and good, but the issue is actually placing the screen somewhere. As I've said in a Tetrinsic log somewhere, I had a "sigma" character inspired design. What I haven't yet mentioned was that I found a new belt type (5PH) and considered a 15x150mm Tetrinsic (with a 15mm diameter body, 46mm rotor length, custom motor), but there is only one type of 0 - 500g FSR available on the market and all the 15mm strip ones are 20 - 10000g, so much less likely to work well for this application. That 0 - 500g FSR has a max sense length of 85mm. The 5PH284 belt is the most ideal.

  In pursuit of thinness, I made the bracket-style design. The main benefit is so that it can fit in a pocket. The easter-egg benefit is so that I can design an RC tracked vehicle mode:

  Since Tetent was also a bit of a stop-gap to Tetinerary, I did consider doing things the Apple Magic Mouse way and mount the screen on the bottom:

  However, there may be a way to do the inverse of the PSP Go, where the screen slides out from under the input panel instead of sliding out to reveal the input panel. If I decide to focus on the 1 : 1 GUI, I could also employ a LG Wing strategy, where the screen swivels out.

  The engineering challenge is going to be to fit a screen, 3Ah battery, 2 speakers and a PCB into a thin formfactor.

• [R][T] Insights from the Master Forge Demo comments

  kelvinA • 4 days ago • 0 comments

  Currently reading the comments in the below video to get more user insights as to what expectations and notable mentions come up for a peripheral that aims to replace the keyboard.

  What commenters were saying

  • Accents / other languages
    • This understandably comes up a lot, and I specifically saw "spanish" more than once.
    • Considering that the original Tetent idea was to chord bigrams and me-in-the-past considered it fast enough to start the project, the idea I've got for all the accents is to dedicate 2 fingers to characters and one to accent modifiers.
    • I've also got to look into what is required for non-latin languages like Japanese / Chinese / Korean / Arabic. 
  • Ambidextrous / one-handed support
    • This is one of the reasons I personally decided to start the Tetent project without first trying out Charachorder.
    • I looked into their discord after seeing a few of these comments and there is a 1-handed layout but it seems that users would like a foot-pedal so that they can access modifiers on the other side more easily than the current method.
    • Unfortunately, the Master Forge seems to only have thumb buttons on one side so it's still not ambidextrous.
  • Game compatibility
    • I'm hoping that the macropad and Xbox inspired layouts addresses this.
  • Learning curve
    • Also mentioned quite a bit.
    • I also noticed when the creator said "I have chords for every single thing here" when he got to the words section of the online teacher, implying that you manually have to set up chords still. This is the other reason I started the Tetent project.
    • Other than moving the user's fingers to exactly where they need to go and applying the haptics they should feel when pressing, I don't think there's more that can physically be done to ease the learning curve. Tetent needs to be able to do this.
  • Accessibility
    • This ties in with one-handedness, but they also mentioned about missing fingers and poor motor control. 
    • I don't think Tetent could reasonably do anything about poor motor control, but typing in english should only need one finely-controllable finger and one kinda-ok-controllable finger. 
      • This also ties in with the learning curve, as users can start off with just 2 fingers and scale up if they feel comfortable.
  • Wireless
    • I also agree. As I've previously mentioned, I usually don't work at a desk, and so my mouse and keyboard wires are more tedious than I initially expected.
  • Younger generation
    • I read a quote a few months (maybe years) ago; "get them in when they're young and impressionable".
    • It's understandable that users wouldn't want to learn something new that might or might not be better than what they already know. It's a very different calculation when "what they already know" is (near) 0.
      • (This is part of the reason why I'm planning on programming Tetent with Rust; I don't know enough about C/C++ to make an entire FW so, from a learning curve point of view, those languages are approximately on equal footing.)
    • For this reason, I'm trying for a 16mm wide #Tetrinsic [gd0041] to accomodate for smaller hands.
    • It would be even better if I could design some mechanism where a user could turn an allen key to fine-tune the spacing, or perhaps just mount the Tetrinsics onto user-accessible slots,
  • Price
    • This is probably the main thing that keeps on getting worse the more I engineer a solution. 
    • I think a Tetent-like device would have to be sub-£60 to have any sort of "mkay, perhaps I should try it" appeal and, due to the prices I've been quoted for #Tetoroidiv [gd0152] motors, Tetent's unfortunately never going to come close.
      • I'm designing this for the hypothetical user that are unsatisfied with the keyboard+mouse combo anyway, so maybe £90 instead of buying a £60 keyboard and £30 mouse?
      • I'm starting to understand why AliExpress robotics kits with decent motors instead of shaky-and-loud hobby servos cost what they do.

• [T] Bundle Adjustment

  kelvinA • 05/07/2024 at 11:26 • 0 comments

  Introduction

  In computer vision, Bundle Adjustment takes multiple images and refines the estimated camera pose between them.
  

  I've been spending the past few days manually doing something similar with the projects Tetoroidiv, Tetrinsic, Tetent, Tetrescent and the newly renamed Tetinerary (which has been renamed from Itinervate as a direct consequence of this Bundle Adjustment).

  I've decided to write everything in this log so that I can refer to it in subsequent logs in their respective projects.

  Considering the phrase "Form vs Function", I'm designating that Tetent = Form and Tetrescent = Function, in that the aesthetics would be prioritised in Tetent and the functionality will be prioritised in Tetrescent.

  Transflective Screen

  The bundle adjustment started when I started searching for screen options when bundle adjusting for Tetent and Tetrescent. Tetent would be fine with a small square screen, but Tetrescent needs to be large enough to reasonably be used as a typing tool, such as Freewrite. 

  I also had the idea of having a similar design for Tetrescent, where instead of a sigma, the side profile would be closer to '>_', resulting in the screen having a 30 degree angle up from the desk plane.

  Not wanting to have to create UIs for two drastically different screens, I decided that Tetent would also use the same screen that Tetrescent used. 

  Since Tetrescent is obviously designed to be used outside (where the sun is), A transmissive screen could not be used. I also strongly oppose sub 60Hz framerates, so an e-paper display wouldn't suffice either. It's possible to design a monochrome UI, but colour would be preferable. Noting some of the complaints people had with the Playdate and the LED mods implemented into the Alphasmart devices, I also needed something that could illuminate in low lighting conditions.

  The first option I decided on was the Asumo 3.4" colour which is £63 on Digikey, which is higher than the £50 I budgeted for the screen but it had the dimensions I was looking for and front-lit. 

  Then I found out that a 3.5", 640 x 480, transflective screen existed. It uses MIPI though, so not exactly ideal. What was ideal though, was the resolution. Tetinerary, formerly Itinervate, uses 640 x 400px optical modules, and this resolution is also very prevailent in the AR glasses industry. If I could implement this transfelctive screen into Tetent/Tetrescent, it would mean that I could then port things over to Tetinerary very easily with minimal circuit changes. It also meant that I could develop, test and validate the software (and battery life) on cheaper hardware before committing to creating Tetinerary.

  The optical module uses RGB888, and I was able to find a similar RGB666 transflective screen from the same supplier, only it's out of stock:

  Eventually, I was able to find a practically identical panel on AliExpress, and it's within my budget too:

  Next, I looked to see if there were any YouTube videos of the panel and there is one that shows that it surprisingly has excellent viewing angles, which is important for Tetent as the screen will be aligned with the desk plane (i.e. facing straight up).

  As the panel was 3mm thick, it made more sense aesthetically for the top part of the sigma to go over the Tetrinsics (instead of the Tetrinsics cutting into it). This then opened up the possibility of putting a 3Ah battery under the panel and small stereo speakers (the same ones that have been featured in concepts in the past) facing towards the user. I'm going to be using dual speakers per ear for Tetinerary, partially because there likely won't be any space for a single speaker over the ear and partially to obtain planar 360 degree audio. 

  The battery move was important, as I hadn't gotten the power performance I wanted out of initial Tetoroidiv simulations and a good solution needs more space than...

  Read more »

• [A] Details page before 12 Jan 2024

  kelvinA • 01/11/2024 at 11:30 • 0 comments

  I'm finally starting to revamp and equalize all my details pages so that the projects can be better understood and information hidden within the depths of logs can be more easily found. The below is the old Details page.

  ---

  Notable Tetent projects, sorted by project log count:

  • Input element: #Tetrinsic [gd0041] 
  • For Teti: #Tetent [gd0090] 
  • Wearable: #Tetent TimerSpy [gd0136] 
  • x86 PC Handheld: #Tetent UMPC [gd0149] 
  • Desktop: #Tetent TestCut [gd0139] 
  • Solar Powered: #Tetrescent [gd0150] 

  Tetent is primarily for #Teti [gd0022], and it's a good idea to think of Tetent as an input device for Teti similar to how the PS5 Dualsense Controller is an input device for the PS5. 

  I'm looking to control my PC from the perspective of a console. Most games designed for a specific console can be fully controlled using the standard controller. Playing Forza with a steering wheel controller feels more suited to the game, but the game can still be fully played with the standard controller.

  Input devices I'm trying to consolidate into a "PC controller"

  • My keyboard
    • My WPM is 60 and it seems like it'll take many years of continued effort to double that. Even if I got to 120WPM, it still would be too slow. After thinking of the R.O.I. of the continued practice, it just doesn't make any "time-finacial" sense.
  • My mouse
    • I'm almost never on a hard, flat surface anyway.
    • Even if I was looking for a new mouse, there's no ambidextrous 12-side-button "gaming" mice.
  • The 3D mouse that doesn't exist yet
    • I'd like to be able to select UI elements that are behind other elements, such as shapes in PowerPoint or edges in Fusion 360.
    • Likely more suited for Mixed Reality experiences.
  • My Spacemouse / 6-axis mouse
    • I've got an old Space Explorer and it takes up my limited desk/table/lap/reachable-floor space and I constantly have to be switching between it and the keyboard.
    • I've also tried to use this as a 2D mouse, and wrote about my experience here.
  • The touch input of my touchscreens
    • I really like touchscreens but the issue with them is the lack of precision, occlusion and the abundance of fingerprints.
    • The lack of precision means that I need to spend more time retrying to press a UI element.
  • My drawing tablet I rarely use
    • I mainly got it as a touchscreen input alternative for Teti for when in triple monitor mode and for writing digital maths notes.
    • Being able to sketch out design ideas with pen pressure is also ideal.
  • My MIDI keyboard I rarely use
    • It's even larger than my keyboard, and I didn't like the key travel distance.
    • I'd like to be able to capture melody ideas wherever inspiration may strike.
  • The XBox controller I rarely use / PS5 controller I never had
    • I think it'll be nice to bring over some of those DualSense controller haptics over to Tetent. 
      • It's unlikely to be as sensory as haptics across the entire palm, but it's likely better than 0 haptics at all.
    • Ideally, Tetent will be able to control some racing game or Minecraft ergonomically. Additionally, whilst I don't play any FPS games, being able to quickly and accurately click on GUI elements seems similar.
  • The finger massager I never had
    • Every slider is motorised; might as well also use them to try and mitigate any fatigue while typing.
  • The ASUS laptop dial / Surface Studio dial I thought was really cool but have never used.
  • The high bandwidth VR controller that doesn't seem to exist on the market (as of 2023) for working in virtual reality.
    • I've got to be ready for when a Pimax 24K or similar headset finally drops.

  Fast typing method

  I like to think of Tetent's default layout as the next Pokemon evolution of chording keyboards: "parallel entry". 

  For a normal keyboard, which would be "serial entry", you'd have to make sure all fingers are perfectly timed so that the characters appear in the correct locations of the word/sentence. Failure to do this causes a few typos ("hte", "ot", "wit hthe", etc) and also makes it somewhat difficult...

  Read more »

• [R] Finds from r/PeripheralDesign

  kelvinA • 11/13/2023 at 20:06 • 0 comments

  Over 2 weeks ago, I discovered r/PeripheralDesign, a subreddit that finds many atypical inventions and products under the umbrella of peripheral devices. Yesterday, I decided to scan through older posts for research and I found some notable projects:

  Uncokeeb

  This project is very notable due to the many similarities with Tetent, and was also made in the persuit of speed and an alternative to stenography. 

  What I'd call "input elements" is what the creator calls "modules", but it's used to select any one of the 26 english letters with a single finger. Side buttons (which are levers to real buttons) are used, so I'd imagine there's less of a risk of Repetative Strain Injury (RSI), unlike #Tetrinsic [gd0041] where the fingers predominantly slide up and down its length. The thumb has fewer keys, and since there's only 27 non-zero states available on the modules, punctuation is put on the end of the word. The character map can be seen here. Just as I plan to do, the fingers only move the distance of about 2 standard key spacings in their design.
  

  u/bluesocarrot also listed the pros and cons of what they've managed to make. As predicted, the fact that the same letter is on each finger contributes to a low learning curve. On the other hand, due to the width of the modules, they need to stretch their hand out quite a bit, and the 27 states also makes it hard to adapt to non-english alphabets.

  To me, the current #Tetrescent [gd0150] concept looks like the "iPhone 15" of this "iPhone 1" prototype; like if you got a bunch of people together to work on and iterate the Uncokeeb across a decade. Obviously, if there's an "iPhone 30" concept somewhere out there, I'd like to know about it. At the same time though, Tetrescent is still just a concept, and I've seen those iPhone 5 concept videos...

  Palm Pro (link1, link2)

  This is notable because I've been trying to find evidence of a keyboard in the past that sensed force. This keyboard is also wearable, but it's not a chorded keyboard. 

  This keyboard uses vibration motors to provide the haptic sensations required to use this kind of device, and it enforces that Tetrinsic needs to do the same to ensure fast and accurate typing.

  Force sensitive resistors are used. The reason I haven't used them for Tetrinsic is partially to do with the ever-increasing length of sensing area, and the other reason was because I was thinking that It'll be hard to get precision since they're non-linear and not made to as tight of a tolerance as load cells.
  

• [A] Tetent Solar Edition: Tetrescent [gd0150]

  kelvinA • 08/25/2023 at 11:27 • 0 comments

  There's 1 single thing this project needs to do to be called "Tetent", and that's to fit into #Teti [gd0022]. Concept4 doesn't fit, thus the solution fails. 

  I still like the idea of a solar powered input device, so I've created yet another spinoff project:

  #Tetrescent [gd0150] 

• [R] Sunpower 125x125mm solar cell?

  kelvinA • 08/24/2023 at 12:29 • 0 comments

   Yesterday, I discovered a new solar cell that has some benefits and drawbacks:

  As you might be able to see, one of the benefits is that there are no lines on the top of the solar cell. This ties into the second benefit, which is that both the positive and negative connections are on the bottom of the cell. This greatly aides in turning this solar cell into a solar panel:

  They're also very efficient -- partly because the entirety of the cell can absorb light energy -- with the panel in the first image acheiving 21.8% efficiency. I'd also imagine that, for a consumer DIY project, it would make Tetent look more professional since solder joints would be hidden on the back. There's also some 3.6W solar cells for a similar price but have visual defects:
  

  I'm not sure the extra 0.3W is worth it over having to see a defect for the lifetime of the device. This 3.7W panel is the highest efficiency solar panel I've found in this size:

  The main drawback for my application is that the smallest square is 125 x 125mm, and the solder pads are at the right edges of the cell, meaning that it can only be cut into 1/2 or 1/3 segments:

  I will admit that, ergonomically speaking, the increased space would be more comfortable. Additionally, the larger the solar absorbing area, the more likely it would actually make a noticable difference to battery life, especially in sub-ideal lighting conditions; a 125mm panel would generate 56% more power than a 100mm one.

  I'm just concerned because the final dimensions of Tetent would be sometihng like 190 x 190mm.

  [25 Aug] This is a render with the panel:

• [T] Focus on solar version? Include reverse PDLC film?

  kelvinA • 08/21/2023 at 12:38 • 0 comments

  Since 

  • I can cut-to-size any photovoltaic cell I desire,
  • creating a MIPI circuit probably takes longer than a photovoltaic circuit,
  • I'd need to source and/or make animation files for the screen and 
  • the screen would reduce battery life instead of increase it, 

  I'm thinking of focusing on the solar version going forward and, once I've got a Tetent that works, consider engineering an LCD backlit solution.

  It might also be possible to find a reverse mode PDLC sheet and, coupled with LEDs on the edges of the acrylic / lexan window, allow the choice of absorbing ambient light energy or a solid white LED backlight. The reason for the inverse/reverse mode sheet is because normal PDLC film requires energy to become transparent. This is the kind of PDLC I need:

  It seems that the name for this material is "PNLC film":
  

• [R][M] Concept4 90mm Square and 5" square display

  kelvinA • 08/20/2023 at 18:27 • 0 comments

  So now I've printed the 90mm, though I've kept the Thumb 2mm from the edge of a 75mm square:

  This is in the event that I use the 4.12" screen. I wanted to see what kind of bezel would be apparent.

  It seems that a 90mm square is large enough for my hands, so the next step was to see if there was any display that was that size. The good news is that there's a single panel that is the size: S050QWS115EN

  It seems that, when the cable is folded, this screen would be max 4.4mm. It also seems that it's straightforward to connect to a PCB as the pinout has a single power pin, MIPI related pins, 2 backlight pins, a reset pin, some "LCM_ID" pin and the rest are either GND or NC.

  The slight issue is that this screen is shockingly recent -- the datasheet was finalised on the 14th of June this year. The price is also "Enquire Now", though at least the MOQ is only 2pcs. I've sent a message to Dwin, the guys that seem to take screens like this and turn them into HMI's, to see if they're developing anything (because if they are, I can focus on the solar cell in the meantime).

  The backlight takes 18V and uses up to 2.3W, but the good news is that the screen acheives a minimum of 900nits, meaning that it's viewable outside. If I ever use this panel, I'd have to make sure to have something like a high frequency backlight circuit so that low luminosities dont flicker.

• [M] Concept4 80mm Square

  kelvinA • 08/20/2023 at 14:04 • 0 comments

  So I've modelled and printed an 80 x 80mm area test print. The thumb Tetrinsic is 4.8mm higher than the finger Tetrinsics.

  I might as well get the bad news out of the way. When using all 4 finger Tetrinsics, my thumb feels like it has no space and Finger5 is very close to rubbing on the edge of the Thumb Tetrinsic on the other side. This diagram I made in PowerPoint helps illustrate this:

  Tetent is already too long to fit in the bottom section of Teti, and adding another 20mm to the bounding box in X and Y does not help!

  The good news is that 4-fingers / 3-fingers-and-thumb configurations line up without anything feeling off-centered or misaligned. It also seems like I'd be able to get away with all 5 Tetrinsics if I position Tetent at an angle:

  If anything... it feels like the actual strat. Still need a tiny bit more thumb space though...

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