Battery powered magnetic cabinet led

Thread Starter

danomano

Joined Jun 23, 2021
1
Hi all,

Althought I'm a Software Engineer for the last 10y, I'm completely new to electronics and I was wondering if you could help me with an easy project.

I want to add my cabinet a magnetic sensor that would light up a led, I've been reading about this a bit and i'm a bit confused.

What materials exactly do I need to get?
1. Battery case that contains 4 AA batteries as each one is 1.5v
2. Reed switch
3. 5v Led Strip

Is that it? am I missing something? what should I look for exactly?
 

ElectricSpidey

Joined Dec 2, 2017
1,871
Just the usual accessories...
Wire
Crimp terminals
Connector for the strip
Stuff like that.

How do you plan to configure your reed switch, you will probably want to have the switch close when the magnet is removed.
 

Externet

Joined Nov 29, 2005
1,667
You chose reed, OK. There is several other methods as motion sensor, already at the hardware/gadget/web store, or with timer, multiple sizes, tilt sense, rechargeable...

----> https://blog.pegasuslighting.com/20...stalling-a-battery-operated-led-pantry-light/
----> https://www.ebay.com/itm/234001246001?var=533635563517&_trkparms=ispr=1&hash=item367b8fa731:g:A-sAAOSwm1JglwJ9&amdata=enc:AQAGAAACkPYe5NmHp%2B2JMhMi7yxGiTJkPrKr5t53CooMSQt2orsSRAQR8FABHjfpFoyRlXhWmXQV5z7zddb0W3%2FEJki7F498pecL3hbeD%2FtheAQ6bxQbRg44KKp5TfXEdZUkxtxVMQifncCmNz6ypKWPNnbyFL4KEA%2BIIhmuSz5CSf4bKNuY7D0DvYt4%2BmBhe2lUzuy6lBGUPlAvEll5%2FVviuSsrqJb8rHf2b8GJ8LrKFwIPBsrUX7vzBNoNJ1GYxKP01SHsmphWeittjy8g1HYrXp096%2BqiwgGmmgfkv4hV3nqt1JrQMAAAv6eJfO8z2lTIBi8HVx7eVv9Om0g%2BP25C91Crn2rXbHJpa5c7SXf18VBoM11EWy%2FJQ9povCID6rvcYrHN3rZR9nRxbPG%2BQ2y41GTYo0XYevBGJDkaER11EOMh8%2Fp8XWQXqA07XG5n8Gvas5al%2FmFZIRkMse67ZjGAJ1eSQo2Jb4LHxJlVADs31rsh%2BRouOHa70JzxtXJN%2BY4UXK3UCH4hB%2BJj0vjVWe7VHwIfFhhuJ%2FW%2Fg5Q0VXuGY8BQeAbpQ%2BEOrtqC7mAU7gLtg84iTAzGvVBONo00ArU%2FOQl63qAplyG%2FyS%2B8%2F2xCpUwwgFtFneEqyKqNunygZz1hjD%2FS8g2a1FItf3Yp25%2BOmBl25NyhbxpuN9f2%2FCzCE533wUunoB5YcIFzuSl%2Fl1%2FATdIF8Sw%2F3XzM90X8iOOGdCVyke8ZpU1fpPAt1UtYvJ7j9If%2BWyQHXBBQIiptAgvtL285DZrbrqyINRhCMq0XAv9HnOlIrs%2Bwl7b8yYwdWxj83PF4gAX2EYX%2FAnRT2pxJ%2BHo3Pk0ZcTYEd4Ka5v2MRrc5C2SrW9h%2BazvpuuqSfVAbt5uY|ampid:pL_CLK|clp:2334524
----> https://www.ebay.com/itm/114845222486?var=414996059789&hash=item1abd4f0656:g:fXcAAOSwCWRgGgkI
door switch without magnet ----> https://www.amazon.com/Cabinet-Ward...abddb&pd_rd_wg=hk6eV&pd_rd_i=B07YTC8VYH&psc=1
 
Last edited:

AnalogKid

Joined Aug 1, 2013
9,385
We need the electrical characteristics of the LED strip. Does it have current limiting built-in? What is its rated current for nominal brightness. Depending on that, a normal little reed switch might not be able to handle the current.

ak
 
What materials exactly do I need to get?
1. Battery case that contains 4 AA batteries as each one is 1.5v
2. Reed switch
3. 5v Led Strip

In some respects, you don't have a handle of your requirements. Your LED strip dictates the power requirements. The battery and LED chosen dictates both lifetime, size, intensity and asthetics. You need to find components that fit this criteria.

LEDs do come in 5V, 12V and 24V but they do so as replacement lamps.

A commercial LED strip typically has some nominal voltage and comes with or without a way to DIM.

Bare LEDS may need a heatsink. The are current driven. They have a nominal current. They have a specified forward voltage drop that varies grossly by color and somewhat by intensity. Don't try to operate a 2.8V, 10mA at 2.8V.
You operate it at 10mA. If you want it to work on 5V then the series resistance is R<=(5-2.8)/10e-3. The power dissipation of that resistor needs to be checked too.

The switch. You need to check the ratings. The LEDS may need a solid state switch.
 
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