Kerry D. Wong writes: I just got myself a couple of Arduino Due boards. While they were released almost two years ago, I have not really got a chance to look at these until quite recently. Arduino Due is based on Atmel’s ATSAM3x8E 32-bit ARM Cortext-M3 processor. The processor core runs at 84 MHz, which […]
Tag Archives: PWM
Wireless servo controller II
Ondřej Karas of DoItWireless writes: We described simple method, how to drive modellers servo. Today, we are going to try to drive this servo from potentiometer connected to TR module ADC. It is reaction to forum thread where is discussion about airplane model control possibility. Check out the video after the break.
App note: Using the AVR’s High-speed PWM
Atmel’s app note on using the AVR’s High-speed PWM (PDF!): This application note is an introduction to the use of the high-speed Pulse Width Modulator (PWM) available in some AVR microcontrollers. The assembly code example provided shows how to use the fast PWM in the ATtiny26. The ATtiny15 also features a high-speed PWM timer. The fast PWM […]
Precise analog voltage from PWM
Destate9 writes: So I’ve been trying to make a constant current H-bridge circuit for a project, and I’m running into trouble with PWM. Right now, all I have connected to the Output compare pin of my PIC32MX microcontroller is a 330uF capacitor (Max ESR of 1.4 ohms according to datasheet). I assumed a 50% duty […]
Fast PWM and electromagnetic interference
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 […]
App note: Fan health monitoring and the MIC502
An application note from Micrel: Fan health monitoring and the MIC502 (PDF!) This section presents a fan monitoring circuit that can be used in conventional MIC502-based circuits employing pulse-width modulation (PWM) fan speed control. The circuit relies on detecting motor commutation to indicate fan operation and does not require a three wire fan with a tachometer output.
Driving a DC motor using software PWM with AVR ATmega
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
An isolated DAC using PWM output
Kerry Wong writes: Arduino‘s (ATmega328P) PWM outputs via analogWrite can be conveniently turned into analog voltage levels through the use of simple RC filters. Since the PWM outputs are not isolated, using them to drive other devices directly could be potentially dangerous. This is especially true if the target circuit uses a higher supply voltage. […]
App note: PWM Margining with the MAX34451
This application note outlines the performance of PWM margining when the MAX34451 is connected to the MAX15041 evaluation (EV) kit: Pulse-width modulation (PWM) margining is a simple technique to adjust the output voltage of power supplies. This application note discusses the effect of PWM on the power-supply output-voltage noise, the enabling and disabling of PWM, […]
RGB LED driven by PWM using Netduino
Embedded-Lab is doing a series of tutorials for the Netduino. The Day 7 tutorial of a series is RGB LED color formation using Pulse Width Modulation: Pulse Width Modulation (PWM) is a digital method of delivering a varying amount of power to a load, and hence can be used to control the brightness of an […]
Spindicator clone with pulse and trail effect
In this video Viktor demonstrates his Spindicator clone with pulse and trail effect project: Although my “original” Spindicator itself was just a clone of this one, mine was well received by the geeks around the world! :) A fellow diy tinkerer made an even better one with PWM control (very cool, indeed!). Recently, I was asked […]
AVR microcontroller based PWM fan controllers
Zak Kemble posted his AVR based PWM fan controller build: So this is a bit of a continuation on my 555 timer based PWM controllers, but now using microcontrollers and MOSFETs instead of 555 ICs and transistors. I made 2 versions, one with switches for speeding up and down and the other with a potentiometer […]
Digitally adjustable precision reference driven via PWM
This simple circuit that converts a 5V PWM signal into a variable precision reference voltage with a rang of -2.5V to +2.5V. Many designs, like a digitally controlled power supply, programmable dummy load, etc, require a Digital to Analog Converter to supply a stable reference votlage. This circuit is cheaper and requires less pins from […]
A Larson scanner just in time for Halloween
Here’s a project for Battlestar Gallactica fans. Mike developed a Larson scanner, or popularized by the scanning eye of the Cylons. The effect is done by fading LEDs with pulse-width modulation to produce the TV show’s hallmark effect. Via the contact form.
ATmega168A pulse width modulation (PWM)
ProtoStack shows how to dim a LED using pulse width modulation and an ATmega168A: Dimming an incandescent bulb is easy. Simply adjust the current down using a potentiometer and you are done. Dimming an LED is another story entirely. When you reduce current through an LED there are unintended consequences like color shifts and dropouts. […]
10-A H-Bridge motor controller
Chris from PyroElectro has posted his plans for a 10-A H-Bridge motor controller that avoids using the the typical controller ICs. He writes: Motor control is the core heart of robotics. Without locomotion or any movement a robot is dull and lifeless. The H-bridge is a tried and true concept for DC motor control. It […]
Convert the Chumby serial port into two PWM outputs
Osman Eralp of Ozbots writes: When I was building my latest Chumby-based robot, I didn’t need the serial port, but I did want PWM signals to control the robot’s wheel motors. Fortunately, the processor pins that are used for the serial (UART) TX and RX pins are multiplexed with PWM outputs. With the proper commands, […]
Arduino varies LCD contrast using PWM
We’ve seen a number of tutorials explaining the use of LCD displays with Arduino. In most the display contrast is varied by use of a potentionmeter. Here’s a tutorial from Hobbytronics which varies the contrast using PWM. A 100uF capacitor is connected between the PWM output and ground to smooth the signal. Using this technique […]
USB IR Toy: Calculate transmitter carrier frequency
See the latest version in the documentation wiki. The USB IR Toy raw IO mode samples and replays infrared waveforms. IRIO mode starts with a default 36kHz infrared transmit modulation frequency. The rate can be changed with the setup modulation command (0×02), followed by a byte that sets the pulse-width modulator match value (PR2), and […]
USB IR Toy transmit frequency
Most infrared remote controls emit modulated light pulses to activate an infrared receiver. Using modulated IR light helps prevent stray light from messing with reception. Pulses at around 38kHz and 56kHz are common, but many values are used. The USB IR Toy’s transmitting LED is driven by a pulse-width modulator (PWM) that can be adjusted […]