View Full Version : Motion-sensitive Red-dot?

Zak Smith
March 26, 2001, 10:30 PM
So I was reading some old threads about red-dots, and one of the arguments against battery-powered red-dots is that having to turn them on when you need it now may be a problem.

Here's my idea.. have a red-dot with three power-on settings:

1. completely off - no power at all.

2. motion sensitive mode - when the rifle is in motion (actually, undergoing acceleration), the reticle will automatically be activated. Once activated, it will stay "on" until the rifle has been motionless for period of time. This period may be configurable, but I would expect between 5 and 30 minutes would be reasonable.

3. locked on - in this mode, the reticle will stay lit regardless of motion or lack thereof.

Models like the Aimpoint Comp/M family currently have modes 1 and 3 only (along with brightness controls, etc).

The idea is that if the rifle is locked in the safe, or it is in your trunk, you leave it in mode #1, so that no batteries are used at all. In the trunk, the bounces of travel will not activate the sight.

If this is a "go-to" gun, then you leave it in mode 2. The reticle will be deactivated after sitting still a short period of time. If you pick up the gun in an emergency, it will automatically activate immediately, and stay lit as long as there is some movement every 30 or whatever minutes.

If you are going to be sitting a long time, totally motionless, and you will want the reticle to be lit, you put it in mode 3.

There is no requirement for moving parts or any sort of room-temperature metal (conductor) in a vial (as in some old toys). Solid-state semiconductor accelerometers exist (e.g.: the G-tech auto-performance tool). Presumably, the sensitivity of the sensor could be calibrated appropriately.

The battery & turn-on issue issue is the only reason I currently prefer the Trijicon ReflexII over the Aimpoint Comp/M.

Combine this idea with one of the new high-intensity, small LEDs (which has hundreds of hours on a single small battery) and you have a very capable system. Modes #1 and #3 could be omitted or made hard to activate so the rifle would more likely be "ready".

Does anyone currently build such a sight? Why not?


March 26, 2001, 10:34 PM
Heck, you're the Electrical Engineer! just do it!

Zak Smith
March 26, 2001, 10:38 PM
Thanks, Abe. :D

I could score one of the surplus SUITs for a FAL, and since they need a new light source anyhow, retrofit it with such a system...

-z (Abe is my brother)

Zak Smith
March 27, 2001, 02:08 AM
According to Aimpoint (http://www.aimpoint.com)'s 2001 catalog (http://www.aimpoint.com/aimpoint_US.pdf), the new CompM2 model has no "off" switch, just the lowest power setting, which is good for 10 years.