Using a Nano Pi, a POE splitter, and a custom project box to create a mobile UDP to RS485/VISCA shading rig

Awhile back, I wrote about how we created a network based VISCA shading rig for our Marshall CV503 cameras we use on stage, to control their various exposure settings. The cameras themselves can only do this via RS485 serial, and our system sends UDP from Bitfocus Companion (we use the Sony VISCA module/connection) over the network, converts to serial at a Raspberry Pi, and then using custom cables, we can send the signal to our cameras over the patchbay.

We’ve been using that system ever since and it works great. We have even recently taken the steps to create custom cable looms that have SDI, CAT6, and power all in one loom to make it a breeze to set up.

Recently, we set up one of these cameras at the back of our auditorium where it’s impractical to run a cable all the way to our patchbay in the rack room at the stage side for a serial connection. We still need to control the exposure, so a solution was needed.

It’s also impractical these days to buy a Raspberry Pi. They have gotten quite expensive, and difficult to find in stock.

A few months ago, I bought a Nano Pi NEO and started playing around with it to see what it could do, since it’s easy to get ahold of and very affordable.

This is the Nano Pi NEO single board computer.

It has an ethernet port, a full size USB A port, and is powered via micro USB. It runs Armbian quite well, so it was very simple to install my existing udp-to-serial nodejs script.

I bought a project box and modified it to fit all the parts. I started with a dremel but I should have just used a hacksaw from the beginning, because that gave me much cleaner cuts. I didn’t want to do any soldering or make custom internal cables, so my box had to be a little larger.

The entire rig is powered by a single POE to USB adapter. This provides the ethernet data to the Nano Pi, and then micro USB power to the Nano Pi’s power port. I also figured out awhile back that you can use a USB 5V to 12V step-up cable to power these cameras, so I put one of those in the box as well.

POE to USB adapter, RS485 cable, and two keystone jacks for serial out. Blue/White-Blue pins for +/-.

We put RJ45 keystone jacks on the box to provide the serial out connections, and we also hot glued the POE to USB adapter to the lid of the box so the connection could be flush with the edge.

It’s certainly crammed in there! The Nano Pi is glued to the bottom, and the rest of the cables are tucked into the box. The USB splitter, the USB to RS485, and the USB 5V to 12V DC cable.

Here are the parts I used:

  • Nano Pi Neo
  • POE to USB adapter – to pass network to the Nano Pi and to give USB power
  • USB 5v to 12v DC step-up adapter – to power the Marshall CV503 instead of using the stock camera power supply
  • USB splitter cable – to split the POE USB power to both the Nano Pi and the step-up cable that powers the camera
  • Micro USB cable – to power the Nano Pi
  • USB to RS485 adapter – this is what sends the received UDP data out to serial
  • Keystone jacks used for the serial connections. We then have custom RJ45 to Phoenix connectors that plug into the cameras. This method allows us to use any standard CAT5/6 patch cable to make the connections in between.
  • Project box to hold it all

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One single POE connection provides all the power and data needed.

Overall, pretty pleased with how it turned out! I like that it’s just two cables – one for the SDI video signal off the camera, and one ethernet to power it all and provide the data connection.

What project ideas do you have for a Nano Pi?

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