Nick Leijenhorst build a 555 PWM circuit to dim his room LED lighting. He writes:
I wanted to dim my room LED lighting with a potentiometer, and decided on creating a solution from scratch to make it more fun and educative. I decided to go with the fairly well-known 555 PWM circuit. To decrease size and for learning purposes I decided on using surface-mount components for the first time. The reason I wanted to make this 555 PWM circuit is actually just to see if I could solder SMD components on home-etched PCB’s, and to see how hard it actually is.
Surface-mount 555 PWM circuit - [Link]
by Aruna Rubasinghe:
The LM317T from National Semiconductor is a popular adjustable-voltage regulator that provides output voltages of 1.25 to 37V with maximum 1.5A current. You can adjust the output voltage with a potentiometer. The circuit in Figure 1 replaces the potentiometer with an analog voltage that you can control from a PWM (pulse-width-modulation) signal. You control this signal with a microcontroller or any other digital circuit. You can use the same microcontroller to dynamically monitor the output and adjust the LM317T.
Control an LM317T with a PWM signal - [Link]
Embedded Lab’s new development board for PIC12F series microcontrollers:
The 12F series of PIC microcontrollers are handy little 8-pin devices designed for small embedded applications that do not require too many I/O resources, and where small size is advantageous. These applications include a wide range of everyday products such as hair dryers, electric toothbrushes, rice cookers, vacuum cleaners, coffee makers, and blenders. Despite their small size, the PIC12F series microcontrollers offer many advanced features including wide operating voltage, internal programmable oscillator, 4 channels of 10-bit ADC, on-board EEPROM memory, on-chip voltage reference, multiple communication peripherals (UART, SPI, and I2C), PWM, and more. Today we are introducing a new development board (rapidPIC-08 V1.0) for easy and rapid prototyping of standalone applications using PIC12F microcontrollers.
Rapid development board for PIC12F series microcontrollers - [Link]
Davide Gironi writes:
This library is an update of the software PWM driver you can find here.
This update implements also progressive start / stop features. So, with this one, you can drive up to 4 motors independently controlling: speed, direction, slow start / stop
Driving a DC motor using software PWM with AVR ATmega - [Link]
The MAX31740 is a sophisticated, yet easy-to-use fan-speed controller. It monitors the temperature of an external NTC thermistor and generates a PWM signal that can be used to control the speed of a 2-, 3-, or 4-wire fan. The fan control characteristics are set using external resistors, thereby eliminating the need for an external microcontroller. Controllable characteristics include the starting temperature for fan control, PWM frequency, fan speed at low temperatures, and slope of the temperature-duty-cycle transfer function.
MAX31740 – Ultra-Simple Fan-Speed Controller - [Link]
jimk3038 @ instructables.com writes:
This instructable fully describes building a PWM driver to control four LEDs from one small Microchip 12F609 board. The original design was called the “Kemper LED Lamp” and I sold a few lamps to several brave folks through my web site. However, I’ve come to discover selling small quantities to a few folks is a major pain in the backside. Hand soldering these together and then selling them at $4 bucks each is no way to make money.
Open Source Microchip LED / PWM Driver Project - [Link]
This is an instructable for making your own PWM (Pulse Width Modulated) flyback driver!
Simple PWM Flyback driver tutorial - [Link]
The Arduino library has always had an “analogWrite()” function, even though the ATmega doesn’t have any way to generate a varying voltage. So why the name?
Well, what most microcontrollers can do is generate a pulse-width modulated signal, also known as PWM. That’s just a fancy way of saying that the microcontroller periodically generates a pulse, of which the width can be varied under software control.
From PWM to voltage - [Link]
TechBitar wrote this Instructable detailing his ANDRUINO, the 2-way Android controller for Arduino via bluetooth:
ANDRUINO is a simple tool to help you control your Arduino (or clone) from your Android phone. It’s both an Android app and an Arduino program. Andruino has a simple Android user interface to 1) control Arduino’s digital and PWM pins 2) send text commands to Arduino 3) and receive data from Arduino over Bluetooth using the ever popular HC-05 Bluetooth over serial module or its siblings.
Andruino should work with other Bluetooth modules with some tweaking but I have only tested it with the HC-05. This is an alpha version that’s running fine on my Samsung Galaxy S2 Plus. Please share your experience running Andruino on your phone.
Andruino: A simple 2-way bluetooth-based Android controller for Arduino - [Link]
here’s another project by Mats the Peweem:
… Peweem – a small unit for to be put on a solderless breadboard to generate 0-100% PWM signals at various frequencies, it can also measure the duty cycle of incoming signals.
Peweem – generating 0-100% PWM signals at various frequencies - [Link]