- Subscribe to RSS Feed
- Mark Topic as New
- Mark Topic as Read
- Float this Topic for Current User
- Bookmark
- Subscribe
- Mute
- Printer Friendly Page
Circuit ti drive LED and halogen lamp using MCU and Shaft potentiometer
QasimRaza
06-15-2016 11:57 PM
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report to a Moderator
Qasim Raza here
I am electronics engineer and just started my carrier in 2015 as design and development engineer. these days i am deisgning a circuit board that can drive 3.5V LED and 3.5V halogen lamp.
In my earlier project which is runnig very efficiently i am just driving a 3.5V/750mA bulb only and light output is being controlled with shaft potetiometer. Rotating potentiometer clockwise light intensity decreases and rotating anticlock wise light intensity increses. The potentiometer which i use is 100K .
the circuit board comprises an autoswitching power supply and LM324 IC. Potentiometer communicates with IC and increses or descrese voltage to bulb accordingly. I
Now I want to make circuit board that can controle light intensity of both LED and BULB with the help of shaft potentiometer. I used PWM to controle the brightness of both LED and Bulb but the problem is in different current rating of LED and bulb .. LED has 330mA current consumption and bulb has 750mA consumption. I have added jumpers to circuit board for bulb and led separately and this jumper communicates with MCU to provide the required current for either LED or bulb
What cahnges should i make in my circuit board to get rid of these jumpers and to make MCU understand automatically whether LED or bulb is connected.
LabviewingToday
06-17-2016 03:15 PM
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report to a Moderator
You can do a duty ratio vs current comparison in your controller. This assumes that the controller has current measurement.
For the same duty ratio (PWM pulse width) applied, the LED should draw less current than the bulb. This can let you gauge whether an LED is connected or a bulb.
06-19-2016 10:23 PM
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report to a Moderator
Thanks for your comment... here i am gonna add scehematic what i have done so far and it worked. But as yu can see in the schematics given in below link .
https://www.dropbox.com/s/ruye37tn9jf8gx9/Current%20wall%20unit%20LED%2BBulb.pdf?dl=0
I am dependent on JS jumpers to communicate with MCU for current adjustment
Guide me in this regard
