• UI: 5-way nav button with external back button; S button; 4-digit 14-segment LED display
  • S button: stop, save, send, share, sync (5-way?)
    • press and release: send/share/save current data according to currently chosen method if in an input mode; sync output to ext trig if in output mode
    • press and hold: pick a new method to send/share/save current data using the same menu used in settings
• interchangeable probe modules, connected by 10-pin shrouded header
  • pins (Keep grounds away from powers if male header is used on body side! (Or just limit current supplied.))
    • ground
    • 3.3 V
    • 5 V
    • main signal in/out
    • aux signal?
    • trigger/S in? (probably better to just use the trigger connector)
    • I²C/SPI for ID, driver, data (2/4 pins)
  • modules can have pogo pins etc.
  • make sure there is no danger when mistakenly connected to a Bus Pirate
    • BP v3 pinout, normal (reversed also extant):

    GND	3.3 V
    5 V	ADC in
    Vpu (0–5 V for pullup resistors)	Aux (freq. in/PWM out)
    CLK	MOSI
    CS	MISO

• RGB LED pointing at probe tip for tiq-style indication
• 4-char 16-seg display
• powered by lipo battery, with 5 V boost converter for display and anything else that needs it
• Adafruit tin for case
• 5-way switch for navigation; button for sending current data to connected computer/website/etc
• shift registers will be on SPI
  • use a transistor to give CS?
  • or just rebuffer the display before asserting OE, and don't care if the SRs hear other SPI traffic
  • if 1 SR/digit, alternate OEs & cathodes using SPI clock line and some gates?
    • Does the SPI clock line run when no data is being transferred?
• op amp for 5 V r–r output, with gain controlled by digipot or LED+LDR?
• docking station?

Modes: everything the Superprobe does, with configurability the original didn't have, plus:

• input
  • voltages higher than 5 V (autoranging, hopefully)
  • resistance
  • duty cycle
  • servo PWM (reads %position)
• output
  • addressable RGB LED protocols
  • analog voltage using DAC or PWM+filter
• more to think up

Also, probe modules can have their own drivers stored in EEPROM chips. Maybe use Bitlash?

Look into: how three-state shift registers work, charlieplexing