Timer Switch for LED night light

[mpmackenna]

I made a really basic LED night light for my kids. It consists of a few LEDs a 9V battery and a switch. I would like to integrate some sort of timer so that it goes off after an hour. Can one of you electronics gurus point me in the right direction? I can solder and use a volt meter but other than that I am pretty ignorant in regards to electronics. Thanks! Mike

 

[audioguru]

Use a low-power Cmos flip-flop that drives a Mosfet. The Mosfet drives the LED. The flip-flop is flipped from a low-power Cmos timer.

We are not a free electronic circuit design site. We help technicians with circuits that they have designed or built.

My night lights are powered from electricity. Don't you have reliable electricity?

 

[MrDEB]

this should get you started.

note the 9v battery won't last as long as say some AAA or AA batteries.
**broken link removed**
Using a MOSFET as a Switch
google = mosfet switch circuit
use a 7555, not the 555. if you need to just cascade two astable timers together where one
triggers the second one
here is an unproven schematic for a long duration timer.Desgned for an automotive app using a relay but a Mosfet would be less current drain.
the rotary switch could be eliminated just use one large resistor. use quality TITANIUM caps as they don't leak as bad (internal ot external, more stable for this app)
**broken link removed**

 

[audioguru]

Nobody makes a TITANIUM capacitor. You mean a Tantalum capacitor.

 

[MrDEB]

I misspelled big time!!
boy your sharp as a tack Audioguru.
Where have you been hiding, haven't seen any recent posts??

 

[mpmackenna]

Wow!

Thanks for all the great replies! Looks like I have a lot of homework to do. I will get started this weekend. Thanks again! Mike

 

[mpmackenna]

Electricity....

We are not a free electronic circuit design site. We help technicians with circuits that they have designed or built.

My night lights are powered from electricity. Don't you have reliable electricity?

So I am in the wrong place? Should I be on another forum?

I didn't wire it to a electrical plug purely out of fear. I am not great with electronics. I figured a battery was less likely to burn my house down. However when I become more familiar with the schematics and how to make it safely I am sure I will elect to use a model that includes an electrical plug.
Thanks again for the help! Mike

 

[MrDEB]

Mike your in the right place.
you have to understand that in this forum there are LOTS of so called electrical engineering students that ask questions that are very vague and expect this forum to do their homework.
First suggestion - post a schematic
second = your ideas on what and how to do your desired project
then this great forum wll decipher and offer suggestions
WELCOME to the forum Mike

 

[mpmackenna]

MrDeb

Mike your in the right place.
you have to understand that in this forum there are LOTS of so called electrical engineering students that ask questions that are very vague and expect this forum to do their homework.
First suggestion - post a schematic
second = your ideas on what and how to do your desired project
then this great forum wll decipher and offer suggestions
WELCOME to the forum Mike

Thanks! I will be sure to follow those guidelines with future posts.

Mike

 

[sahu]

So I am in the wrong place? Should I be on another forum?

I didn't wire it to a electrical plug purely out of fear. I am not great with electronics. I figured a battery was less likely to burn my house down. However when I become more familiar with the schematics and how to make it safely I am sure I will elect to use a model that includes an electrical plug.
Thanks again for the help! Mike

ur r in right place.............
if u r intrestesting pic microcontrller,may be i can help u

 

[audioguru]

Many of our little projects are powered from an AC-DC adapter that we call a "wall-wart". They are certified to be safe and have a low voltage DC output with a low current.

 

[mpmackenna]

Wall-wart

Many of our little projects are powered from an AC-DC adapter that we call a "wall-wart". They are certified to be safe and have a low voltage DC output with a low current.

Thanks, I will look into that item. I hadn't thought about using an external power supply. Mike