UNDER CONSTRUCTION
This article is under development. It is about an alternative approach to mirrors and cameras for security and observation for a mobile environment – in this case, the office on wheels “Labora”. From the FIAT factory, a mediocre reversing camera and console monitor is available for the Ducato – it does its job, nothing more. However, the side mirrors are excellent. An interior mirror is missing and my current solution with an electronic mirror – with an additional reversing camera – is so unreliable that I want another solution. This will be an article about hardware such as cameras, monitors and computers on the one hand, and software such as ZoneMinder and Linux on the other.
Table of Contents
Common pitfalls
Or: Current solution reviewed… What was wrong with the current solution – an electronic mirror recording both front and back?
- Electronic interior mirrors have too little screen brightness in strong sunlight.
- The built-in front camera delivers reasonable videos.
- Despite being high resolution, the rear camera is a PITA.
- Something like: doesn’t work, reboot, doesn’t work, reboot, works. I’m done with it.
- Okay, now I understand… (Some?) modern car lead-acid batteries are never full in order to absorb energy from braking. Voltage is lower as result and long, too thin, power lines create problems.
- During night time the light sensitivity is not enough to make it a valuable addition.
- Something like: doesn’t work, reboot, doesn’t work, reboot, works. I’m done with it.
Back to the drawing board
ZoneMinder
What then? The idea of ZoneMinder starts to come into some zones in my mind…
Personal note…
About ZoneMinder, I decided to do a post on the forum. Consideration: In my life I did too many things that didn’t work as expected. Money thrown away? Well… No, I’ve learned a lot! However, ZoneMinder is a serious application for this purpose and using it depends on getting some support in exchange for publication in order for others to learn. So I am excited to get my hands and head dirty.
Some points…
- First of all, I am not (yet) familiar with ZoneMinder but I want to give it a try. However, creating a proper system is a lot of work and costs much money. So, the least I want is a feeling of investing in a good way, in the right direction.
- Mentioning ZoneMinder first means that I want to create hardware around this software – normally it is the other way around.
- Did I mention it is going to run on Linux? Xubuntu to be more precisely and that is the software part for now.
- Apache is used, separate system in order to avoid security breaches.
- Dedicated smartphone with hotspot turned on for internet access.
Hardware
Camera’s
IMX415 seems to be a good choice. A hardware based encoder is offered as a package of PCB’s. Novatek offers encoders, for example NT98566. Smallest footprint is possible by utilizing PCB’s in a custom made housing. Data over ethernet cabling. I bought one for testing.
Computer
Energy consumption is critical. On the other hand, some computing power is needed. A proper configured DeskMini idles at 10 Watt, based on an AMD Ryzen 5 PRO 4650G for example. In my situation, this choice can be justified. Power supply: LFP12V>StepUp19V.
Lots of complications like dark performance and monitor switching are to be expected.
Lots of question marks…
Monitor: micro HDMI or USB on dashboard, or ceiling, flippable. Something like ASUS ZenScreen OLED MQ16AHE or ASUS ZenScreen OLED MQ13AH.
Power supply
Cameras run on 12 V, computer on 19 V. Of course, everything can be controlled from 230 V with power supplies, as 230 V is permanently available.
On the other hand, this does mean first going from LFP to 230 V and then another conversion. More interesting is a direct conversion from LFP.
Problem with this is that “buck converters” have to have a certain voltage difference as a minimum. And LFP is very close to 12 V. Fortunately, there are also “buck-boost converters” that can solve that. That problem does not arise when converting LFP to 19 V with a “boost converter”.
It is beyond the scope of this article, but “buck-boost converters” are also a great way to avoid exposing LED lighting to voltages above 12 V.