12V Brightness Control Module. - Page 1
Forum section: electronics / beginners

author: Nickk2057
author_rank: Regular Contributor
timestamp: October 23, 2014, 03:26:44 am
content: Hey guys. am trying to make an LED 12V brightness control dimmer for my LED's but am not sure of what i can use out of old electronics. (which i have a ton of them around the house and two sheds) any idea?

author: the_memristor
author_rank: Newbie
timestamp: October 23, 2014, 08:26:52 am
content: Hey Nickk2057, you can use the good old NE555 for generating PWM to control the brightness. A nice circuit can be found here:http://www.reuk.co.uk/LED-Dimmer-Circuit.htmI build it up myself several times and it always works like a charm.

author: Nickk2057
author_rank: Regular Contributor
timestamp: October 23, 2014, 02:34:34 pm
content: Quote from: the_memristor on October 23, 2014, 08:26:52 amwell the LED's is 12V but 17W what would i use to handle the power?

author: jlmoon
author_rank: Unknown
timestamp: October 23, 2014, 02:43:09 pm
content: Drive the 555 with a Power Mosfet.. look up IRF seriesshould do the trick

author: the_memristor
author_rank: Newbie
timestamp: October 23, 2014, 02:49:05 pm
content: Quote from: Nickk2057 on October 23, 2014, 02:34:34 pmJust replace the motor with your leds (D3 is not needed by using LEDs)

author: Nickk2057
author_rank: Regular Contributor
timestamp: October 23, 2014, 03:33:00 pm
content: Quote from: the_memristor on October 23, 2014, 02:49:05 pmfrom what i see on that link and on that image is that the LED's will not power all the way down (turn off) on the 555 circuit. but then i seen that i COULD use the Arduino board with a 5V regulator in the circuit to power the Arduino and a MOSFET to the light. i will post a pic in a sec of the lights i am using.EDIT: here is the image of the lights i am using. NOW MIND YOU that i have modded them to be only used as 12V. the one on the right is 17W and the left is 15W

author: Nickk2057
author_rank: Regular Contributor
timestamp: October 23, 2014, 03:45:27 pm
content: also what i am wanting to use these for is to help my friend in his photography by making some lights to help in saving him some money.this is one of the photo's that i helped in the lighting at a shoot with them with a prototype of the lights i did that is a simple on-off.

author: the_memristor
author_rank: Newbie
timestamp: October 23, 2014, 08:16:33 pm
content: Wow! As I scrolled down the topic on my smartphone your picture was shown full-screen and I nearly got an heart attackVery good photo by the wayYou're right, the range dutyrange of the 555 circuit will between 5% to 95%. I used a potentiometer with a build in rotaryswitch to switch the lamp completly off. Like this one:You can certanly use a Arduino for PWM generationSimple connect a potentiometer (voltage divider configuration) to a ADC pin of the Arduino and set the PWM out according to the ADC value.But take care when selecting the MOSFETs, for example the IRFZ 14 seems to be big enough with I_DS_Max = 10A. BUT if you look to the "typical output characteristics", you will see this FET can only drive at VGS = 5V (output voltage of an arduino pin) at a VDS = 0.3V (RDS_on = 0.2 Ohms * 1.5A (I_DS)) a maximum current of 1A. -> Would be a bad choiceBetter: IRFZ44ZPbF with an I_DS_Max = 51A seems much to big, but has much better specs than the IRFZ 14.It's only an advice to be on the safe side