praveen @ circuitstoday.com writes:
PWM or pulse width modulation is a very common method used for controlling the power across devices like motor, light etc. In PWM method the power across the load is controlled by varying the duty cycle of the drive signal. More the duty cycle more power is delivered across the load and less the duty cycle, less power is delivered across the load. A hex keypad is used for controlling the speed. The speed can be varied in seven steps using the hex keypad. Arduino UNO is the type os arduino development board used in this circuit. The circuit diagram of the PWM motor speed control using arduino is shown in the figure below.
PWM motor speed control using Arduino - [Link]
Nich Fugalfrom @ Makeatronics is working on a BLDC motor controller.
Icall it a smart BLDC commutator. In a nutshell it’s a dedicated atmega328 that monitors the hall effect sensors on a brushless DC motor and takes care of the commutating and driver circuitry.
It’s smart because it has the ability to extract and keep track of motor position while monitoring the hall sensors. There’s also an option to plug in a quadrature encoder for higher resolution. The position can be sampled via a sample and hold input and communicated to a host controller via SPI.
I designed it to be an easy to use black box for interfacing with BLDC motors. All the host controller has to do is feed it direction (high/low) and PWM and the rest is done for you.
BLDC motor control using Atmega328 - [Link]
by Kalle Hyvönen:
I bought a small aquarium (54l) as an impulse buy and I needed some lights for it, so naturally I wanted to use LEDs. I also needed a timer for the lights. I also wanted the lights to fade in and out when they were going on or off as a cool effect.
I ordered four Cree XP-G R5 LEDs (cool white, apparently too warm of a light will cause algae growth) and a one amp (switching) constant current supply (with PWM support) from LED-tech.de. I had some Maxim DS3234 real-time clocks with a serial bus (SPI) which looked easy to implement so I decided to use one. I also had one spare Arduino board so that was going to be my microcontroller of choice. I used a laptop power supply as the power source.
LED aquarium lighting with an Arduino based PWM timer - [Link]
praveen @ circuitstoday.com writes:
In this article we explain how to do PWM (Pulse Width Modulation) control using arduino. If you are new to electronics, we have a detailed article explaining pulse width modulation. We have explained PWM in this tutorial using 2 examples which will help you learn how to control LED brightness using PWM and how to control DC motor speed using PWM.
PWM Control using Arduino – Learn to Control DC Motor Speed and LED Brightness - [Link]
by Susan Nordyk:
The LT8471, a dual PWM DC/DC converter from Linear Technology, employs two internal 2-A, 50-V switches and an additional 500-mA switch to facilitate step-down, step-up, and inverting conversions. Each 2-A channel can be independently configured as a buck, boost, SEPIC, flyback, Zeta, or inverting converter.
This broad range of topologies and output configurations makes the LT8471 useful for a wide range of industrial and automotive applications. The converter operates from an input voltage of 2.6 V to 50 V, allowing it to be used with input sources ranging from single-cell lithium-ion to automotive batteries.
The LT8471 is capable of generating both positive and negative outputs. Its switching frequency is programmable and synchronizable from 100 kHz to 2 MHz. The device’s 50-V switches achieve overall efficiencies of up to 85% for buck and inverting applications. Operating from a 6-V to 32-V input, the LT8471 delivers up to 1.5 A at 5 V and 650 mA at –5 V.
Housed in a 20-lead, thermally enhanced TSSOP, the LT8471 costs $3.75 each in lots of 1000 units. An industrial-temperature version is priced at $4.13 in like quantities. Both versions are available from stock.
Multiple-topology DC/DC converter integrates dual 2-A switches - [Link]
A solar charge controller regulates the voltage and current coming from your solar panels which is placed between a solar panel and a battery .It is used to maintain the proper charging voltage on the batteries. As the input voltage from the solar panel rises, the charge controller regulates the charge to the batteries preventing any over charging.
Arduino Solar Charge Controller (PWM) - [Link]
ajoyraman @ instructables.com writes:
PC sound cards form a readily available Signal Generator for testing electronic circuits. The utility of these signal generators is limited because the outputs are AC coupled and limited to ±2V.
Taking advantage of the two channels provided by the sound card this Instructable shows a scheme which uses one channel to output the Sin/Square/Triangle waveform with a fixed gain, while setting up a 441 Hz PWM square wave on the second channel. This PWM waveform is converted to ±8V averaged and summed with the first channel to provide a DC offset controllable by the duty-cycle setting.
PC Sound Card Signal Generator Interface - [Link]
This relatively simple circuit uses a 6-V DC supply with a PWM current-source configuration to provide efficient, adjustable dimming of a white LED over a wide range, needed to accommodate the unique lighting needs of an optical microscope over its magnification range from 40× to 1000×. by James Campbell
When the built-in incandescent light source of my venerable Olympus microscope failed after many years of use, I decided to design a reliable modern replacement. A 1-W white LED (SEOUL X42182, 350 mA max, Vf = 3.25 V) was the obvious choice to provide high brightness and full-spectrum light without the heat of incandescent or xenon arc lamps. The microscope lamp brightness needs to be adjustable, however, to accommodate the different objective lenses, which offer magnifications from 40× to 1000×.
Current Source For LED Microscope Illuminator Provides Full-Spectrum Light - [Link]
Marios Andreopoulos writes:
A few days ago I wrote a blog post about Arduino and EMI. By using fast PWM and a plain breadboard wire, I was able to detect electromagnetic interference using a usb TV tuner, with its antenna near my circuit. Not only that, but by manipulating duty cycle to create a primitive form of amplitude modulation, I was able to transfer through EMI a very simple audible signal (few notes of one of the most famous riffs) in many frequencies and up to 1.76GHz
Fast PWM and Electromagnetic Interference - [Link]