I prefer to use IR motion detectors which activate IR lights. So if someone is blindly stumbling through the brush, the IR lights (which will run on 12 VDC) will light them up without them knowing it, unless they have NVD's. Lights similar to this: https://www.amazon.com/CMVision-IR130-198-Outdoor-300-400ft-Illuminator/dp/B004F9LF7E The lights will illuminate a large area if you're wearing night vision goggles.
But my low tech solution is a big dog, she sees, hears, and smells intruders way before I notice them. 
Suggestions on NVDs?
Nemo
Armasight Spark Core, the "poor" man's PVS14.
Over the last couple years I had countless conversations with people who had an interest in something that can allow them to engage targets at night with a helmet mounted not weapons mounted sighting system....but without the high pricetag of a Milspec unit such as a PVS-14.
Generally the answer invariably was "You gotta pay to play" or "Such a thing does not exist".
However I never believed that... and two yrs ago I had an opportunity to put together just such a set-up and compare it to my existing milspec PVS-14
The goal was to assemble and test a
complete configuration with tube, IR laser, IR light, helmet, helmet mounts etc for 1300 dollars or less.
Again this is for a
complete set up not just the tube...
This is what I got (all prices approx. retail. If I secured a sale price for any item I will list a good retail price instead so as to not skew the numbers):
-Armasight Spark Core $485
- OTAL (milspec IR laser) $340-390. So less than half the price of a DBAL or PEC2 type unit that features IR laser AND visible Laser. This features ONLY IR laser. But that is our high pay off feature so I judged the OTAL sufficient for an economy set-up.
- Armasight mount #170: $185. I also purchased from my vendor on Armasights recommendation their #70 mount . But ithis seems designed as an adapter for a regular PVS14 mount w/ JArm. This may give me better fit according to Customer Service.
- Inforce Weapons Mounted Light, w/ IR, usually priced between $140-160 dollars. I found it on sale for 100 bucks but I believe this low price cannot be relied on for cost planning and "count" it as $150 cost.
- Lancer FAST (Bump) Helmet for $85 shipped.
Total system cost approx. $1250
In order to test I exercised this unit by duplicating to the best of my ability the environment encountered in light patrolling and also night time live-fire.
First the Bad:
- No gain control, Brightness comparable to lowest third gain setting on a PVS14, so is not terribly bright
- A little bulkier and heavier than a PVS14 tube
- The Armasight Mount #170, is clearly intended to mount this unit on a shroud equipped helmet like the Lancer I was using... it works but just barely.
While the mounting seemed reasonably secure. The adjustments in general were a bit iffy. I was able to make it work but in the end even with the adjustments maxed out for distance (mostly by where you screw the "arm" onto the Spark Core) the unit was still too close to my eyes. I had to take off the eyecup). The "Steps" of flipping down the unit cannot be changed via the screw that backs up that bearing. As a a result the tube was not perfectly level in front of my eye. some adjustments to the helmet padding were able to overcome this to a great extent.
Mount is serviceable but needs improvement. Customer service says they have an adaptor which can make a regular PVS14 mount work. I have this adapter and may try it in the future for better fit.
The good:
-Picture surprisingly clear and free of distortions.
-Has both diopter (-5 to +5) and distance focus adjustments. (So for most folks who wear glasses they could use the monocular w/o wearing them).
-Used it in a moderate rain with no ill effect on the unit afterwards (though raindrops on the lens interfered with vision at some point...but this would be same for any other unit regardless of price so it doesn't count as a negative)
-Was able to engage targets with IR laser without resorting to IR Light illumination from my weapons mounted light. IMHO his is a KPP (Key Performance Parameter) for nearly everyone.
-Responds real well to an IR WML and this extends engagement distance to maybe 90m (=100 yards). Without Active IR WML I observed being able to see (and engage via IR laser) a man sized target at 30-40m.
- Price! Priced in the high 400s this unit is an incredible Value. Also now one doesnt have to stress so much about the units well being anymore.. If its gets stolen/lost.. sure thats bad... But its not 3-4k+ bad!
Just understand that it is not a PVS14 and do not except Milspec performance out of it.
What you can expect though is to have a moderate but practical and useful Nighttime engagement capability with this unit and this arrangement is dramatically superior over mounting a sight on your weapon direct ( as most other affordable units are used)
JRH Enterprises helped me put this kit together.
They usually focus on milspec stuff and this unit is not on his site.. but Robert said he would do special order as long as the buyer is educated to not expect a PVS14.
Robert also has good deals on OTALS:
www.jrhenterprises.com/OTAL-C-Infrared-only-laser-OTAL-CIR9056.htm?categoryId=-1Can't say enough good things about Robert from JRH. He comes out to train and is simply one of us.
PS: If I were to do it again I would consider to spen the extra 800 bucks for the Armasight gen 2 unit with gain control. A good jump in capability but also a substantial jump in price.. So for many not worth the extra $$.
This configuration as it sits now will allow night engagement via helmet mounted sight, a significant capability.
