• Prototyping w/ 74HC595 Shift Register

    Basim Cheema-Sabir • 04/01/2025 at 22:00 • 0 comments

    Unfortunately, I ran into some hiccups with the v4 PCB, and since it mostly involves small SMD components, debugging it proved difficult. Instead, I pivoted to testing some basic shift register logic with a more well document shift register, the 74HC595, with the Arduino Nano. Below is a video of 3x2 braille cell-style array of LEDs flashing through the braille alphabet while being controlled by the shift register.

    The Arduino code can be found in braille_flash.ino in the GitHub.

    Next Steps:

    I will try to control an H-bridge IC with the shift register and hopefully be able to control current flow through the coils. Once that works, I will begin designing the v5 PCB implementing these new shift register/h-bridge ICs.

  • v4 Parts + PCB Assembly

    Basim Cheema-Sabir • 03/11/2025 at 07:14 • 2 comments

    Update 3/11/2025:

    Shift Register and H-Bridge ICs arrived, and PCBs arrived. Soldered SMD components on using microscope and fine soldering tip.

    Next Steps:

    Write Arduino code to control shift register and send input signals to H-Bridge ICs.

  • PCB v4 Schematic & Design

    Basim Cheema-Sabir • 12/18/2024 at 03:27 • 0 comments

    Update 12/17/2024:

    Researched different ICs for controlling a full 6-dot braille cell.

    TLC6C5912-Q1 12-bit shift register, to control all 12 outputs associated with the full cell. Two outputs are required for each dot to drive current in both directions.

    DRV8212DRLR H-bridge motor driver IC, to take digital signal from shift register and enable current flow in a specified direction.

    Completed PCB v4 design:

    3D render:

    KiCad design:

    Completed PCB v4 Schematic:

    (coils not shown)

  • PCB Arrival, Completed First Prototype + Successful Initial Testing

    Basim Cheema-Sabir • 11/14/2024 at 06:17 • 0 comments

    Update 11/13/2024:

    PCB Arrival

    PCBs arrived from JLCPCB (pictured below)

    Completion of First Prototype

    Soldered pin headers, bolted 3D-printed assembly to PCB

    Successful Testing

    See video

  • Printed first prototype parts, Designed first prototype PCB

    Basim Cheema-Sabir • 11/04/2024 at 21:18 • 0 comments

    Update 11/04/2024

    First prototype PCB design consists of two coil setups, one of which is a single layer, the other being a two layer version, connected in series. Each coil is 6mm in diameter with a 0.15mm trace width/clearance, and approximately 9 turns per layer.

    PCB design:

    CAD model:

    M2 bolts will be used to align and fasten the outer 'chamber' part over the center of the coil.

    The two parts were printed on the Creality Halot Lite SLA 3D-printer using clear ABS-like resin.

    Printed parts (microSD for scale):