Before You Buy Plate-Reading Cameras, Count Your Power Ports

If you are ever asked to approve a camera system for a neighborhood entrance, a parking lot or a loading dock, there are two things in this story worth your time. One is that a vendor added a feature I needed within hours of my asking for it, which is a reminder that asking is free and often works. The other is a small, boring electrical detail that would have left my cameras working perfectly all day and completely dead at night, exactly when you actually want them.

Let me set the scene. I run a project called GuardSense, which uses the cameras at the front of my neighborhood to do license plate recognition, software that reads the characters off a plate as a car drives past and turns them into text a computer can work with. The point is to classify the traffic coming in: is this a visitor, a vendor, or a resident? I have sold a lot of cameras over the years and deployed plenty of both IP and analog ones, but plate reading was a new corner of the market for me.

Why a special camera, and why this brand

The cameras I chose are made by Ubiquiti (NYSE: UI), and they sell a model specifically labeled as an LPR camera. Those differ from their regular cameras in three ways that matter. They do the plate recognition on the camera itself rather than shipping video somewhere else to be analyzed. They have an infrared light, an illuminator the human eye cannot see that lets the camera work in the dark. And they have HDR, high dynamic range, which handles the awkward situation where a reflective plate is bright and everything around it is dark.

I searched around, looked at a bunch of different plate-reading cameras, and landed on the Ubiquiti ones partly because I already know the product line more or less from the wireless side of the house. As plate-reading cameras go, they are not expensive.

The problem: the data was there, but I could not get at it

Here is where it got frustrating. The camera could read a plate just fine. What it would not do is hand me the plate. I wanted to pull the six or eight characters into my own software so I could analyze the traffic pattern, and there was no clean way to do that. It did not feed into the Dream Machine, the all-in-one box that acts as the network gateway and the controller for the cameras, and there was nowhere else I could pick it up, because there was no API I could call.

An API, application programming interface, is just a defined doorway that lets one piece of software ask another piece of software for information in a predictable way. Without one, you are stuck improvising. The firmware, meaning the software baked into the camera itself, would push a plate out via API only for a vehicle it already recognized, or for a suspicious vehicle it had been told to watch for. That is backwards for my purposes. Everybody who pulls into my neighborhood is somebody I do not know; if I already know who they are, that defeats the whole point. I need the unknown plates.

So I went looking for workarounds, and found one. The team behind Home Assistant, an open-source home automation platform, had figured out that the plate text was sitting inside the system's log files, the running diary of events that equipment writes for troubleshooting. You could scrape the plate out of the logs. It worked, and I wired it all in, but it was janky. The catch with a hack like that is that it is not a supported feature, so the moment I update the firmware on the Dream Machine or on the cameras, there is no promise it survives. It was better than nothing. It was not something I would build a business on.

I asked. The feature appeared.

So I reached out to Ubiquiti and said, here is exactly what I was looking for, and the product does not do it, can you make this happen? Within a few hours, a checkbox appeared on the dashboard that pushes unknown license plates out via API. Fully supported, no log scraping.

One important caveat: it is not in the latest release notes for the software, which is precisely why I wanted to write this quickly. If you go looking for documentation confirming this exists, you may not find it yet. It is there. Go look at your dashboard.

Kudos to that team for turning a piece of feedback into a shipped feature. That only happens if somebody asks.

One thing I still do not know: which other camera models this works with. I bought the LPR-specific cameras deliberately, for the infrared bounce and the reflective-plate handling. But my understanding is that plate recognition runs on a number of their cameras, and I have not tested that yet.

The power lesson that would have cost me every night

This deployment requires a Dream Machine, so I used the Special Edition model because it has ports that can deliver electrical power to the cameras over the same network cable that carries their data. That technique is called PoE, Power over Ethernet, and it means you do not have to run a separate electrical outlet to every camera location. There are tiers: standard PoE delivers a certain amount of power, and PoE+ delivers meaningfully more.

I have three cameras. The Dream Machine Special Edition has only two PoE+ ports; the rest are standard PoE. So I had to buy a separate PoE+ injector, a small in-line device that adds power to a network cable, to get the third camera running.

Here is the part that would have bitten me quietly. If you plug one of these plate-reading cameras into a standard PoE port, it works perfectly during the day. No problem at all. But at night, when the infrared illuminator switches on, the camera draws more power than a standard PoE port can supply, and the camera simply stops functioning. Great all day, totally dead after dark, which is exactly when you want a license plate reader running. If nobody physically checks at night, you could sign off on an installation that is only half doing its job.

What to do with this

• Budget for PoE+ on every plate-reading camera in the design, not just on the ports your controller happens to have. Count your PoE+ ports before you count your cameras.
• Test the cameras after dark before you sign off on the install. Daytime footage proves nothing about nighttime performance here.
• Go look at your Ubiquiti dashboard for the new checkbox that pushes unknown license plates via API, even though it is not documented in the release notes yet.
• Stop relying on the log-scraping workaround for plate data, because it may not survive a Dream Machine or camera firmware update.

Questions worth asking your installer or vendor

• How many cameras in this design need PoE+, and does the equipment we are buying actually have that many PoE+ ports, or are we buying injectors?
• Has anyone verified plate capture at night, on site, with the infrared illuminator active?
• Is the way we are getting plate data out of the system a supported feature, or a workaround that a firmware update could break?
• Where does the plate data go, who can see it, and what software is consuming it?
• And the simplest one: have we actually told the vendor what we need? Ubiquiti turned my request into a shipped feature in hours, and that only happens if somebody asks.

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