Ongoing trail camera project

In a previous post (voltage regulator draw at no load), I took Hero's advice and ordered a 6 volt SLA battery from radio shack.

Now for the next problem stage! I want to be able to light up the area at night and I would like to slowly turn on the lighting over about 4 or 5 seconds. Something like the soft start motors on expensive power tools. I've experimented with a R-C series circuit. Could I use something like this to slowly turn on a transistor up to saturation? This would be upon initial aplication of power to the circuit from a timer. The lights will be 12 volt automotive type or eventually maybe high out put LEDs I've also thought that possibly I could use an adjustible voltage regulator controled by the same R-C delay in the adjustment circuit. Please comment on these ideas or suggest something more simple. A scematic example would be great. Thanks in advance

Telling us the amount of current would help, and the voltage required by the lights. It's not a complicated circuit, but the specifics are important.

A bulb that I was experimenting with is 12 volts 1.7 amps 7 ohms of resistance

To prevent heating the transistor, and to prevent wasting your battery capacity, you should use a Pulse width modulator dimmer. Easy to do in software in a PIC; a little harder to do using an opamp integrator and a comparator to create the switching signal.

The wasted energy in 5 seconds???

ps, it is hard to turn a 12 volt lamp fully on with a 6 volt battery. Would you like to try another light source?

This is the basic shape of a simple time delay. The 3 driver transistors are required to keep the capacitor a reasonable size. It might be done with 2 driver transistors and careful research to select the right ones, but this will work with stuff most ppl have in their junque box.

Then again, there is the microprocessor route, if that is simpler for you.

Thanks. That will give me something to experiment with. The lights will operate on 12 volts apart from the 6 volt camera battery stuff, at least that is the plan so far.


Aaron

Recalculate the last resistor for 11 volts over .17 amps = 65 or 68 ohms and P = 11^2/68.....1.78 watts
Put in a 4 or 5 watt resistor, 68 ohms.

Hey! very interesting. I'm planning to do something similar soon. I too have a camcorder that never gets used that i want to use. I'm a complete newbie to the electronics/microcontroller scene, but i think i'm going the microcontroller way.... just need to learn the basics first! my idea is to make a servo based solution so it can be used with all cameras, without hacking them. That way the controller can be used with any camera, it's just a matter of changing the script and make a new outer "shell" where the servos are mounted.
Like you i´m thinking a PIR to trigger camera startup, a light sensor (resistor) to determine whether a servo should flick the switch on the cam to go night-mode and also turn on an IR LED floodlight, a servo to push start / stop and then power off. Then comes other considerations, do power stay on if PIR keeps detecting movement, etc. Anyway, don't know if it gave inspiration or not, but i'll look forward to learn more about your project! Pictures and diagrams will be greatly appeciated!

I'll post as it goes together. I'm using a Harbor Freight driveway alert for the PIC sensor. It will alow placing the sensor anywhere and not reliant on the aim of the camera. I have the timer circuit done, using a 556 dual timer. One part controls the time the camera is on and the other sets a delay in being retriggered. Both are adjustable. I'll go with incandesant lights for night because I have all the stuff to do it. Maybe high power LEDs and radio controled in the future. I'm using a mechanical system to turn on the camera and push the record button (motor and solenoid). I once made a shutter control for a still self winding camera using a under voltage motor winding up a fish line to pull on a lever to push the button. So I'm using PROVEN technology this time LOL.
This forum is great and those responding are educating me good. THANKS.

Aaron

BYCHON

I breadboarded a circuit today as you suggested and it works but not exactly as expected. The lamp begins to come on at 7 seconds and then goes bright in one second. I used the resistors and capacitor as in drawing, 2N3904s for the first two driver stages and a 2N5493 for the 3rd. The voltage across the lamp starts rising very slowly but with increasing speed. It seems like we need to start out with or get to the curent required for a dim lamp sooner but slow down the final increase. Is this possible?

By the way. On your diagram, it looks like you give a part # for something and I'm having trouble reading your TIME formula ie. the figure after RC

Thanks for your or anyone elses ideas

Aaron