Bluetooth Minidisc Remote

From Hackstrich
Revision as of 18:09, 27 August 2023 by SarahEmm (talk | contribs) (Logic rail needs to be shut down when not connected to a device, to make battery last a reasonable time idle)

The Bluetooth Minidisc Remote will be a remote for portable Sony MD players that also transmits their audio over Bluetooth.

Status

  • 2023-08-22: Started putting ideas together after getting back from a trip where I used a Bluetooth transmitter dongle connected to an RM-MC11EL a whole bunch.

Design Goals

  • Same basic functionality you'd have on a regular Sony remote, though with an OLED screen
  • Ability to remap buttons, if you want to use it with different portables or you want different controls in different places
  • Ability to lock ("hold") all the controls except volume, since I've always wished remotes allowed this
  • Bluetooth audio transmission to BT Classic endpoints (A2DP SBC)
  • Ability to play/pause the MD device via the play/pause button on the Bluetooth receiver
  • Transmitter will stop sending audio when nothing is playing (rather than sending silence like 3.5mm BT transmitters do)
  • At least 8 hours of battery life on a charge hopefully (since with Bluetooth and an OLED, the remote will need its own internal battery)
  • Custom 3D-printed enclosure that will hopefully not be that much bigger in L/W than the flat rectangular remotes for Kenwood portables, though will be a bit thicker because of the amount of stuff I'm trying to fit in

Design Overview

  • Cypress 343026 module for MCU (built-in Cortex-M3) and Bluetooth Classic
  • Fujitsu ELW2106AA OLED display
  • DA7218 codec chip?
  • Internal battery, charged via USB-C

Power Planning

Requirements:

  • Input power
    • Li-poly pack, 3.0 - 4.2V
  • OLED
    • OLED Drive - 15.5 - 17.5V (16.5V nom)
    • Logic - 1.65 - 3.5V (3V nom)
  • BT/MCU
    • Logic - 2.3 - 3.6V (3.3V nom)
  • Codec
    • Core - 1.7 - 2.65V
    • IO - 1.5 - 3.6V

Required rails:

  • Logic - 3.0V (shut down when not connected to a MD device, fed via TLV62568 buck converter)
  • Codec core - 1.8V (switchable, fed via second TLV62568 buck converter)
  • OLED - 16.5V (switchable, fed via AP3012 boost converter)