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Optocape V0.1

Optocape is a photocoupler interface cape for BeagleBone Black, with integrated video serializer.

It was designed for CNC projects based on many 3D Printer control systems. While the 3D printer capes provide enough signals, the larger motors require isolated power supplies. This PCB uses DIP socketed optos; typical in industrial machines for reliable opperation.

It can be used in many applications requiring isolated I/O and a big touchscreen.


  • 15 high-speed outputs (isolated)
  • 10 high-speed inputs (isolated)
  • UART Tx Rx (isolated)
  • 4 opto relay outputs (500mA)
  • 12 bit color LVDS video (CMOS)
  • 4 analog inputs (CMOS)

Mechanical Specifications

Size 3.14x3.15 inches
Layers 2
PCB Thickness .063 inches
RoHS Compliant Yes


Optocape Pin Usage

This cape was originally designed for a CNC milling machine. The I/O was designed to accomidate four axis with step, direction, enable, limit switches, spindle, LED light and more.


The signal outputs are divided into five sections. Each section is powered through seperate V and GND nets, allowing the BeagleBone and each section to opperate from seperate power supplies.

In addition to the signal outputs there are four on-board opto relays, rated up to 500mA.

Pin 9.25 is connected to an on-board indicator LED.

Pins 9.11 and 9.13 are connectord to dedicated Tx/Rx optos for serial communication (BBB UART4).


The inputs are also isolated, and resistors are on-board. Attach 3-6 volt input signals directly to Optocape, or add a resistor for higher voltages.


The cape includes a LVDS serializer compatible with many flatscreen LCD panels. The cable is not included, and varies depending on your LCD. The mating connector is a 2MM header (14 pin, 2 rows).

Four-wire touchscreen is supported through pins A0-A3 of the BeagleBone Black.

The LVDS & analog pins are at CMOS level, powered by BBB VSYS, and are therefore ESD sensitive. Use caution if the LCD backlight uses a high voltage flourescent. LED backlights are preferred, and can be switch on/off by the on-board relays.


Device Tree

EEPROM Support No
Part Number BB-OPTOCAPE1
Version 00A0


Open Source Yes
System Reference Manual Yes
Schematics Yes
PCB Files Yes
Gerber Files Yes
Bills of Materials No



To go back to the cape list, please click BeagleBone Capes