G sensor related?

[tangopapa]

I've been trying to figure out how in-vehicle cameras calculate the amount of g-force needed to trigger the video recorder on a dash-mounted camera.

Can anyone point me in the right direction? I'm looking for an industrial standard that would define "aggressive acceleration or deceleration" Basically, what is the value needed that would indicate erratic movement in a vehicle...

Any help would be great....camera sites aren't helping me out too much but I'm sure there are some folks here that would know

Thanks

Tim

[shorod]

What type of application are you referring to here? A camera that would be used to record accidents, or ones that are used for in-car video during track events? If during track events, most of those are started shortly before the car gets on the track, they continue to record for the entire session, then the video is downloaded and post-processed.

If you're referring to an application that would capture accidents, the cameras could be triggered by the brake pressure switch that some vehicles have, the TPS or WOT discrete, and/or airbag trigger, or as you mention, various g-sensors within the car could provide that as well. But I'm not aware of any cars that come standard with such dash-mounted cameras and these discrete signals may not be readily accessible.

-Rod

[tangopapa]

This would be a sensor inside the camera that would only begin recording when certain values are met ( example: sharp turn, slamming on brakes, rapid acceleration )...these measures are probably measured in G's or even meter's per second per second.

What I'm trying to determine is what companies typically use as a standard before the camera, in this case, would be turned on and begin to record.

Thanks

[shorod]

Regardless of if there is a standard, that field is one that should be adjustable. A high horsepower, normally aspirated car with low rear end ratio is going to accelerate with greater force than a turbo charged car with AWD. You'd want to be able to set the camera to trigger in either case, but you may not want the trigger point hard coded so low that doing a power brake on the RWD will cause the camera to trigger.

You could take a look at the 60 foot drag slip times of the type of car that you are looking to apply your camera to and get a pretty good idea of how many [acceleration units] the car is accelerating with. Or if you are looking to apply this camera for accident situations, there probably is a standard on when the airbags are set to deploy. The trigger point for the camera will be different depending on the application.

-Rod

[Moppie]

Originally Posted by tangopapa

I've been trying to figure out how in-vehicle cameras calculate the amount of g-force needed to trigger the video recorder on a dash-mounted camera.

Can anyone point me in the right direction? I'm looking for an industrial standard that would define "aggressive acceleration or deceleration" Basically, what is the value needed that would indicate erratic movement in a vehicle...

Any help would be great....camera sites aren't helping me out too much but I'm sure there are some folks here that would know

Thanks

Tim

G'day, welcome to AF.


I take it your referring to the driver monitoring systems that being fitted to trucks etc?


My understanding is these systems run all the time, constantly recording and over writing footage.

If the system detect an "event" then it saves the last 30secs of footage before the "event".

What defines and event is going to be totally dependent on the system used.
The systems I've used used a combination of G senors and connection to the brake pedal, or ABS system.

As I understand it, the G sensors measure movement in all directions, so hard acceleration would not set them off, but hard braking, or a sudden swerve to avoid something would.
What the value set in the devices are I don't know, at a guess I would say somewhere around .5+ G would be needed to set them off.


Why do you ask?
Has someone fitted one to a vehicle your driving?