dashcamera ups

So I'm trying to build an arduino ups for my dash camera. I can probably use something simplier like a 555 timer or something but don't know how to use it properly.

My goal is when the power stops from my car the ups will stay on for 3 minutes and then shutoff.

When the power from my car is on it will charge the ups's battery as well as power the dash camera.

The problem with my dash camera right now is that when the power from the car stops, it no longer goes into a powerdown cycle and shut off properly, so my last video is always corrupted. So I'm hoping the extra 3 minutes will allow the last recording to finish.

Any help would be appreciated.

I have a module that charges a 3.7v lipo as well as regulates the 3.7v to 5v. I need someway to stop the power going after the arduino senses that the car power is off and starts the 3 minute timer and stops the power going to the dashcamera.

Thanks

mrteach: My goal is when the power stops from my car the ups will stay on for 3 minutes and then shutoff.

Why would the power from the car battery stop? Compared to the needs of a dashcam the car battery is a huge UPS.

All you need is a simple circuit using the Arduino to turn off the camera a few minutes after the engine is shut down.

...R

Robin2: Why would the power from the car battery stop? Compared to the needs of a dashcam the car battery is a huge UPS.

All you need is a simple circuit using the Arduino to turn off the camera a few minutes after the engine is shut down.

...R

Yes when i meant the car battery stopping i meant the engine being shut down.

My problem is I don't know what the circuit would look like to get the arduino to turn off the camera after a few minutes.

You need to tell us how the dashcam gets its power.

My guess is that it needs very little current and you could get the Arduino to control a transistor that acts as a switch in the dashcam power line. Alternatively you could arrange for the Arduino to control a relay.

Of course you also need some means for the Arduino to know that the engine has been shut down. A simple way to do that might be to monitor some cable whose power is only on when the engine is on. Just make sure not to connect 12v directly to an Arduino I/O pin.

And you might also want the Arduino to shut itself down after it has shut down the dashcam - though that may not be essential as it would not draw much energy from the battery of a car that is used every day. One way to shut down the Arduino is to supply its current from the same line as the dashhcam so both go off at the same time. However if you do arrange for the Arduino to switch itself off then you will need some means to get it to switch on when the engine is started. Not so simple, but perfectly possible.

...R

Simplify your life - 12V OFF timer

Sounds to me like the internal rechargable battery is no good. I don't see how running an external power source after the engine shuts off would be of any help as the dvr stops recording on a preset time after lack of movement is detected. This is usually around 30 seconds or so and the job of the internal battery . If you keep it externally powered it will be jumping from idle to record on every little movement detection.

So to answer most of the questions. I'm using the cigarette lighter adapter for usb so the dashcam runs on 5v via usb not through 12v.

My ideal method would be to use only 1 usb port to power the arduino/charge the arduino battery and the passthrough 5v power as well from the usb port cigarette lighter and turn cut the power bypass after 3 minutes of it realizing that the engine is off (because cigarette lighter would not be providing power to the arduino anymore)

The internal battery is most likely the problem, but last time I opened and changed a battery, for some reason the whole thing didn't work afterwards (or perhaps it was broken before changing the battery). However the internal clock still works for some reason and I know it doesn't have a clock battery and uses the same lipo. If I leave the dashcam uncharged for a long period of time it will not keep the time and everything will reset.

I've been reading a bit and think I need this transisitor FQP30N06L.

buy a camera with battery