This project is a small automatic cooling system for home theater rack. It supports 2 temperature sensors for different zones in the rack and 2 12V PWM fans (standard for PC case cooling).
There is a power switch connector for a switch mounted on the casing (will be designed and 3D printed later). A reset button is provided mostly for reprogramming purpose. There are 4 buttons for setting up temp...
IGBTs and bridge rectifier must be cooled with large heat sink with appropriate isolation pads. It's better if water cooled. IGBT gate push-pull transistors does not need cooling. Resonant tank capacitor is not included. R3 is PWM duty cycle adjustment, R7 is resonant frequency tuning. Use R2 and R4 to set max/min duty cycle limit. Grounding must be appropriate, don't use wall socket grounds.
Using a 555 timer and a mosfet to control the speed of a DC motor with a potentiometer.
Video here https://www.youtube.com/watch?v=5nwNKPs2gco
Usando un circuito integrado 555 y un mosfet para controlar la velocidad de un motor DC con la ayuda de un potenciometro.
Video aquí https://www.youtube.com/watch?v=Q2N2OEicXJE
**555 timer based PWM LED dimmer**
This project uses PWM to turn on and off a LED (or a strip of them) really fast and changes the duty cycle (Fig.1) so that the human brain perceive it as the dimming of the LED(s). This means that the MOSFET doesn’t have to drop large amount of voltage, this makes the device very energy efficient.
Universal board for LED control.
- Atmega8/328 on board with programming connector
- PCA9685 for 16 channel PWM up to 1.5kHz (eye-safe frequency), 12 bits per channel
- cheap ULN2003 with paired outputs for 1A per channel (2-3 meters of RGB 5050 strip per connector)
- or SOT23 MOSFETs if you need more power
- BT05 bluetooth module or MAX485, control by wire or wireless. DMX512 is possible.
- This circuit is used to control the speed of a 12V motor using a PWM signal.
- The transistors Q1-Q4 are there to invert the signal, to amplify it and to derive the voltage still present at the MOSFET at the moment of switching off. D1 and R6 also serve this purpose.
- D2 terminates the induction voltages of the motor.
- C1 and C2 keep the voltage supply stable.
- MP1 measured against G...
# Multi purpous PWM led driver #
WiFi PWM Led driver light hub for white, warm white, rgb etc use (8 chanels).
Connects to home automation system (for exemple Jeedom).
This drives series/parallel led strips, not adressable leds / led strips.
2 PCB designs to be able to mount it in round or rectangular enclosures.