PineTime Hardware Wishlist

This page contains a list of things people wish PineTime did differently

Hardware

• Long pressing the button should power-cycle the watch without any software being involved
• Other display technology could be explored.
  • A transflective LCD
    • Increased readability in bright daylight
  • OLED
    • Self-emissive display (pixels emit their own light)
    • Allows for lower power usage with mostly black screens
    • Allows for low power visual notifications (imagine an always-on small red square in the corner to indicate a notification)
• Touchscreen with configurable sensitivity
  • Ideal for gloved fingers and water droplet resistance
  • Preferably it should remain capacitive, as a resistive touchscreen would have too many trade-offs.
• A slightly bigger 256×256 pixel display
  • This resolution is preferable for its binary alignment for low-level simplicity
  • It has the property that its X and Y coordinates are each addressable with a single byte, with no bounds checking
  • Its total number of pixels is a power of 2 (65536), and each pixel is addressable with exactly 2 bytes.
  • The IBNIZ (Ideally Bare Numeric Impression giZmo) virtual machine, designed for minimalist demoscene graphics, has chosen 256×256 for its virtual display specifically for code efficiency.
  • If PineTime also chose 256×256 then it would be a target platform for unclipped IBNIZ demoscene programmes, which would be really fun to play around with on one's wrist!
• Full screen refresh is very slow
  • A full 16-bit redraw on the display takes at worst 120ms, which is 8Hz
  • Modest optimization is possible by adopting 12-bit color
  • A smooth scrolling/usage/animation experience would be 30Hz minimum, preferably 60hz
  • Display redraw is currently bottlenecked by the nRF52832 maximum SPI clock (8MHz).
  • The nRF528(33/40) has one high speed SPI master which supports 32MHz, still well below the ST7789 maximum
  • Parallel data transfer could be an option, but using more GPIOs (which don't look available)
• Some sort of scroll wheel would be nice for convenience.
• Changed GPIO assignment so more functionality is available (i.e. NFC and VSYNC)
• Wireless charging, or Qi Charging capability
• nRF5840 update
  • 32MHz HS SPI, QuadSPI, CryptoCell + Secure Key Storage, more RAM, a coprocessor and the possibility to expose USB through power pins
• Preferably a pre-certified MCU module with a ceramic antenna
• Version without sensors but maybe bigger battery
• Pins on the programmer connector to allow UART while developing (currently there is a TX test point on PCB). (Note: There's ARM SemiHosting, ITM and Segger RTT)
• Connect SDO of ST7889 LCD controller to MCU.
  • Allows MCU to execute READ commands
  • Possibility of leveraging ST7889 RAM to save MCU RAM?
• LCD must be centered on case. Currently is not and watchfaces seems different when clock is put on the other wrist.
• A NFC antenna around the case, connected to the NFC pins.
• Used sensors should be NDA-free and preferably also blob-free for easier development
  • Possibly replace BMA421 accelerometer
    • The BMA421 doesn't have a public datasheet
    • Special attention should be paid to advanced features, such as step counting integration or flick detection.
• PineTime SoC could support USB or have a FTDI chip with the relevant pins exposed.
  • It could allow flashing a sealed device, just like Arduinos work.
  • Alternatively, an USB-C port could be added that provides these features.
• A bigger pulldown resistor for the power button
  • 100k still leaks a noticeable amount of power when the button is always on.
• Ceramic Bluetooth antenna for better signal reception
• An external RTC circuit
  • Allows the main MCU go to deep-sleep while retaining time.
  • Allows time retention through MCU reset.
• Ultra low quiescent current PMIC
  • In theory could provide a hard reset capability based on button press
  • Better deep sleep/shipping/storage/off lifetime
    • A nano-power system timer IC could in theory provide a RTC, MOSFET-controlled deep sleep, watchdog timer and button-controlled reset
  • Built-in "fuel gauge" for better estimation of battery capacity
• Small Piezo Buzzer
  • Use case would be for very short beeps (think old-school casio watch) as notification.
  • Of course developers can PWM other frequency to make it sing, but piezos tend to be shrill.