The DIY approach: HDMI pattern generator

UPDATE #2 (22/02/2018): I’ve written an update which can read here.

UPDATE #1 (31/05/2017): I’ve finally gotten around to working on this. I’ve made a lot of progress and will post a blog post about it shortly.

Being able to calibrate a monitor is crucial to the work of a Digital Imaging Technician but what happens when you need to check the entire chain between camera and monitor?

Obviously a live signal needs to be pushed down the line but the ACs are often too busy to hook up a camera to satisfy your curiosity. Instead I suggest a test pattern generator could be used to generate a consistent live feed without the need for expensive equipment.


Pattern generators are expensive

But one quick link on cvp.com tells us that pattern generators are ridiculously expensive… which defeats the purpose.


Cineroid PG32e – £708.00 inc VAT

Link: CVP

This one has all the proverbial bells and whistles and can output a number of selectable test patterns at variable framerates and resolutions. It also has built-in SDI outputs which eliminates the need for any external converters.


Going the DIY route

The Atomos device is the best candidate and out of all options has the best value. But as a pure HDMI pattern generator it is still far too expensive. The alternative requires more effort but is a lot cheaper.



Raspberry Pi Zero W – £9.60 inc VAT

Link: Pimoroni

The Raspberry Pi Zero is an extremely tiny computer (check out those micro USB ports) that requires little power but yet can output a 1080p HDMI feed.


The Raspberry Pi Zero will act as the brains of the device but I’ll need a case to put it in and the ability to select different framerates and resolutions without a need for external peripherals (keyboard and mouse).


The difficult part

A bespoke case has to be designed and 3D printed. After that selectable toggles and buttons (to select framerates and resolutions) have to be installed and soldered onto the mainboard.

All of those selectable options have to be programmed into the open source software that will replace the OS and run when powered on. This requires a degree of expertise that I simply don’t have… yet.

In addition: An internal battery would be ideal but not a necessity. This has to be factored into the case design as the module has to be purchased and soldered onto the mainboard.


Summary

The effort to create a HDMI pattern generator is considerably higher than simply buying one. However, like the development of any product the initial cost and effort is in the R&D.

Once the initial hurdles are overcome manufacturing more of the devices will be a lot easier.

If you are interested in helping out with the development of this device then let me know through the contact page and I’ll make sure to reply ASAP.