VMAC PiHat v3 – Specification


VMAC PiHat (Video Matrix Audio Controller)

This is a new project (Feb 2022) – details to follow and was previously shown under HAMKit brand.


#Specification VMAC-2












The VMAC PiHat is an updated version featuring FOUR A/V inputs and ONE A/V output, complete with OSD (On Screen Display).

Based on the original HAMKit VMAC AV PiHat v2.4, it is a small board which provides a very flexible Audio and Video Switching Matrix, with on-board DTMF Decoder, OSD Graphics, Video Signal Detectors and EEPROM.

Size 85mm x 56mm x 15mm.  Software is open source.

This may principally be used as a Raspberry Pi add-on board, or connected to other devices such as Arduino or Microchip, via i2c.

Typical applications for the VMAC PiHat v3 are:

  • ATV and DATV Repeater Control Logic
  • ATV home, mobile or portable stations
  • FM Repeater Control Logic
  • Audio / Video matrix controller
    • ATV/DATV
    • CCTV (Matrix or Auto Cycle Select)
    • FPV (5GHz Video Camera Receivers)
    • Video remote switching
    • Audio remote switching

The VMAC PiHat is supplied as a populated tested SMT board with through hole components soldered, with exception to the Pi Header.   VMAC PiHat v3 Specification.

The VMAC PiHat is easily software controlled from the Raspberry Pi using your preferred coding language such as Python and all software provided is Open Source in order to encourage people to develop and help each other with ideas and applications.

Default Configuration:

The default VMAC PiHat Input/Output configuration is:


  • 4 x Video RCA inputs
  • 4 x Audio RCA inputs


  • 1 x Video RCA outputs
  • 1 x Audio RCA outputs

 These maybe altered by updating the input and output resistors and capacitors as shown in the schematic.

Supplied Built and Configured: 


  • 4 x Video Inputs (3 x RX for example)
  • 4 x Audio Inputs (3 x RX for example)
  • 1 x Pi A/V input (Test Card for example)
  • 1 x Video Outputs (TX and Stream/Monitor for example)
  • 1 x Audio Outputs (TX and Stream/Monitor for example)

Ready Built Kit:

  • 1 x VMAC PiHat v3.0 (Fully built, almost ready to plug into a Raspberry Pi 2, 3 or 4 and tested)
  • 1 x Pi GPIO Header Riser Soldered for Raspberry Pi 2, 3 or 4
  • 2 x JST 6 pin cables
  • 1 x Set of Pi mounting posts/bolts
  • 1 x Pack of 0805 components (allowing change of input types if needed)

Note: A Raspberry Pi is NOT included in this kit.



All software and examples are on the Wiki

User Guide:

The User Guide is a dynamic document and the latest revision and datasheets can be downloaded here

Our new Wiki pages will continually expand with useful information and code examples.


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