IPVMU Certified | 01/05/15 11:00pm
I think power would be the major issue, even if camera positioning were not. Usually that power comes via the vehicle's electrical system recharged by alternator/engine, but when the main power is cut off it would be purely battery power.
Even from the parasitic drain of a few watts per hour for inactive systems (motion detectors), batteries would drain pretty quick. Throw in a few system high-wattage 'false motion' events, and the drain is even faster.
A separate power system might be the best solution, but that would add cost and maintenance to the idea.
You might think about installing a siren/strobe like a Amseco Potter style siren/strobe triggered by a door switch. Also think about leveraging the strobe on top of the bus if it is equipped. Drivers will need the ability to arm and disarm them so utilize a hidden bypass switch. Powering up a DVR/NVR may take too long. Make enough noise, both audio and visually, the punks will not stick around.
- What kind of IR cameras, Analog SD?
- Currently used for driver's live view only?
- Are they vandal resistant themselves?
- Do they have edge storage?
- How much power do the cameras draw? With and without IR if you know.
- Are you trying to catch perps in the act with mobile alert from Dvr, or next working day?
If vandal resistant and have edge recording (I know long shot) you could consider a Dvr-less solution, where you would check footage after the fact.
Have you considered a lead acid battery that would charge when bus is in motion? (Not good if busses will be typically unused for many days at a time.)
IPVMU Certified | 01/06/15 06:35am
Have you looked into "bait car" programs that have been successfully run by local and State Law Enforcement Programs to see if they have addressed similar issues that you are presenting in your post? This is probably the best starting point for your recent posting. Theses programs have been quite successful in New Mexico.
There are a lot of mobile DVR options, or even many "normal" DVRs that run off 12 volts. Cheap options are available. (not sure if you have analog or IP cameras on the busses).
Is there some reason you can't put cameras *outside*, around the yeard, to see who is entering? The assumption being it would be easier to power those of off normal 120V power.
A couple of cameras and mobile DVR might kill the battery over an extended period, but you can also add a cheap trickle charger (I have this unit on a car that gets stored). You'd have to run an extension cord to the bus, but even if the cord was unplugged, the battery would be topped up enough to keep the system running.
Wireless backhaul is an option, but that might use as much net power as a small/simple DVR.
You could replace some or all of the cameras with SD-card storage versions.
Pro Focus LLC | 01/06/15 03:01pm
Just a quick idea, how about a second battery dedicated for the camera system. You could use a large group 31 AGM (~125Ah) battery that is connected to the main electrical system of the bus, but separated by a solenoid to keep it from draining the main batteries at night. When the bus is started, the solenoid allows the alternator to also charge the camera battery.
As far as cameras are concerned, a 720p IR vandal dome with an SD card should suffice. Most have 12VDC inputs and should be able to make it through the night, figuring a 10-12 hour span. If more time is needed, simply increase the number of batteries. With a 1A draw, a 125Ah battery should be able to run over a weekend without charging. Your limiting factor would be if you needed multiple cams per bus, or longer run times for holidays, summer break, etc.
Also, if capture of the subject is paramount, I wouldn't use any deterrent type of systems, such as alarms or strobes. Give them the false comfort of staying a while. The longer they are there, the more frames you will have to review. You will only need to pull a recording after an incident, so this offline method should work fine.
What about catching them in the act? You could use a video verification system such as Videofied. (Disclaimer: I am a Videofied rep) This seems like something right in their wheelhouse. If the area were defined, controlled (fenced in), and "armed" at night, it could be very effective. The video would be B/W and at CIF, but it would be used as verification as opposed to identification. Factors to consider: 1) is area controlled (fenced in, no after hours traffic) 2) system acts like an alarm; needs to be armed and disarmed (at shift open/close?) 3) area of coverage 4) cellular coverage for area by provider. I'm sure I'm leaving some details out, but just a quick 2cents.
This is a great issue for discussion. Lots of places for miscommunications. Having dealt with this several times, here is what I have learned.
1. Not everytime, when people say they want to catch the vandals are they really willing to pay for that solution. Most often, it is less expensive to deter the behavior. I know they want to clear complaints, but, money tells the tale of true dedication.
2. Simple battery powered alarms like those travel alarms people use on their hotel doors would make enough racket to scare off some people. travel alarms Not too expensive.
3. Lock the bus doors with hasps and padlocks? Not too expensive.
4. Motion sensing floodlights on buiding with audio announcement? Not too expensive.
5. Temporary security guards deployment overnight. Good for a contract company.
Before we move straight into making battery powered systems and pulling cruddy lowlight video from a mobile system, I'd suggest an exploratory session with the end-user to really see what they want to achieve and what they can purchase. Public schools can be dreadfully underfunded.
There might be some easier solutions available.
Although, A nice battery powered, lowlight/IR, motion sensing, edge recording solution is sexy too. How many busses can we sell this into?