Hi, this is Wayne again with a topic “LED Lamp with Sleep Timer”.
One of the best ways to help you get to sleep is to start turning down the lights in your house before you go to bed. To make this easier, i designed an automatic dimming lamp when it’s on it acts like a regular dimming lamp, but it also has a sleep timer that will make the light gradually dim over a set period of time. Here’S how to make it. This is the circuit that i designed for this project. A 7805 voltage regulator provides a steady 5 volts for the control circuit. A variable resistor then sets the voltage at the gate pin of a power mosfet.
This allows the variable resistor to control the brightness of the leds. Like a dimmer, however, when the switch is opened, the gate voltage is set by the capacitor. This voltage slowly drops as the capacitor drains through its parallel resistor. As a result, the leds gradually dim over time.
The timing of this dimming cycle is determined by the values of the capacitor in its resistor to build it start by finding a dc power supply. Then we need to calculate how many leds it can power divide the power supply’s voltage by the leds voltage to get the number of leds that will be wired in series, then divide the power supply’s current by the led’s current to get the number of leds. That will be wired in parallel.
In this case, it gave a total of 40 leds. Now we’re ready to prototype the circuit on breadboards be sure to use the full number of leds to properly test out the circuit. If everything is working, the way that it should, you can solder all the parts onto a large piece of perf board.
Next, we need to prepare the lamp start by cutting the power cord and removing it from the body of the lamp. Then open up the head of the lamp and remove the light bulb, you may need to unsolder the cord from the power switch in order to completely remove it now route, the new power cord through the body and into the head of the lamp solder. These wires to the circuit board also connect the power switch to the board, with jumper wires to mount the variable resistor start by drilling a hole in the side of the housing, then insert the variable resistor through the hole and secure it in place with a washer And nut the last thing that we need to do is attach the led array to the inside of the lamp to prevent shorts.
I applied a piece of tape to the back side of the board. Then i applied a generous amount of hot glue and stuck the board in place. Now all you have to do is reassemble. The lamp with the lamp turned on you can use the variable resistor to adjust the brightness of the leds, just like a regular dimmer to activate the automatic dimming function, just flip the switch and the leds will begin to slowly dim and turn off.
This can make a really useful sleep timer, thanks for watching and check back next week for more diy hacks and how to’s you .