Pulse-width modulation, is varying the duty cycle of a rectangle wave, usually with a constant frequency.
0
votes
0answers
11 views
Criteria behind selecting pwm frequency for speed control of a dc motor?
I'm working on a speed control circuit for a brushed dc motor(24v,500rpm,2A,4kgcm). The main components that I plan to use are pic16f873,4n25 opto coupler,IRFZ44N mosfet, BY 500 - 800 diode(for free ...
2
votes
3answers
90 views
Driving Permanent Magnet DC Motor via PWM
SUMMARY:
I am currently trying to finish up a DIY project I've been working on for a while: Building an electric potters wheel. I acquired a treadmill and salvaged quite a few good parts from it, and ...
3
votes
1answer
94 views
arduino pulse to transistor power maximum
Hello I want to get a confirmation that what I am doing is not going to fry my Arduino Mega.
The sketch I am using to send a pulse out on pin 8 to a 2n3055 that is switching 12 volts is this:
...
0
votes
1answer
49 views
Shifting between PWM options
I'm using a Freescale MC9S08DZ60 microcontroller, and Ive written the code for applying PWM on a specific pin.'This is an attempt for Breathing Effect of LED, a question i had already asked - LED ...
1
vote
0answers
38 views
Parallel, low noise motor driver design with L293D [duplicate]
I'm designing a very basic motor driver circuit for 12V DC brushed motors to be connected with my microcontroller. The motor needs to be driven in forward and reverse
My objective is to do that with ...
12
votes
1answer
186 views
Sine signal generation using PWM
We are unable to generate a sine signal properly using a MC68HC908GP32 microcontroller. PWM description begins in page 349. Clock frequency is 2.4MHz, while we have used 7 kHz PWM by using the ...
2
votes
2answers
112 views
Arduino PWM shield with npn transistors
I'm using a PWM shield (http://www.practicalmaker.com/products/arduino-shields/pwm-shield-assembled) which allows to extend the number of PWM pins for an Arduino.
In my project I'm using NPN TIP120 ...
0
votes
2answers
234 views
LED Breathing Effect
Please consider the following code:
for(;;)
{
int i=0;
TPM1C2VL =~ (i<<1); // Channel Value(Lower)Register.
TPM1C2VH +=TPM1C2VL;
}
ALTERED CODE
...
2
votes
1answer
70 views
Simplest design approach for PWM control with power MOSFET
I'm designing an application in which the current running into a load is controlled by PWM. A microcontroller generates a PWM cycle at 20kHz and this signal is used to control a MOSFET which is ...
0
votes
2answers
65 views
PWM controller to meet EMI/EMC regulations
I'm designing an application in which the current running into a load is controlled by PWM.
A microcontroller generates a PWM cycle at 20kHz and this signal is used to control a MOSFET which is ...
1
vote
2answers
60 views
Controlling a Servo with a TLC5940 (calculating PWM setting)
I'm trying to control a few servos and a bunch of RGB-LED from an arduino board. To do that I'm going to chain together a few TLC5940 chips. The issue I'm trying to resolve at the moment is what PWM ...
4
votes
2answers
7 views
Is it possible to remap the PWM output to other pins?
The Arduino Uno has PWM outputs on pins 11, 10, 9, 6, ...
10
votes
2answers
23 views
Why do some pins have `~` signs next to their numbers?
I was looking at my Arduino Uno and I noticed that symbol by digital pins 11, 10, 9, ...
-5
votes
1answer
77 views
How to multiplex leds using a microcontroller? [closed]
I saw this project online for a simple binary clock:
It's a very simple circuit. What I can't figure out, is how you can control each row separately.
The parts list is as follows:
1 - High ...
0
votes
1answer
26 views
What are fast and slow decay timings in the Allegro A3201 low voltage meter?
In the A3901 Low Voltage Meter Driver datasheet Figure 8 on pg. 10 shown below indicates what the output "IOUT 2/3-4" will look like given input "IN1/3 or IN2/4".
But Figure 8 does not mention ...
1
vote
1answer
95 views
Soft-Starter PWM Noise
I have developed a soft-starter for a project of mine. I am using an Arduino Uno to generate PWM to an OAC-5 relay that turns on and off the voltage across my bridge rectifier.
Here is a simple ...
0
votes
2answers
355 views
Arduino controlled PWM PC Fan
I am looking at getting 2 Evercool EC8015HH12BP 80x10mm (4-wire) PWM fans. However, i am looking at controlling the fan speed with the arduino via the PWM pins.
I found the following diagram that ...
1
vote
2answers
169 views
Apply PWM signal to PIN of a Microcontroller
I am using the MC9S08DZ60. I have been give a circuit diagram according to which i must program the micro-controller. I am using Code warrior with Processor Expert which allows me to initialize the ...
1
vote
3answers
217 views
Dimming multiplexed LEDs
I'm multiplexing 32 LEDs in a 4:8 configuration on an ATMega328 and am trying to dim them with what is probably a completely naive understanding of PWM. Note: I'm multiplexing them directly with 12 ...
1
vote
2answers
256 views
PWM Motor speed control using PIC; What mosfet to use
I have a 5V PIC16f877a controlling the speed of the motor 12V which has a power rating of 8W; the current will be around(600mA) am I correct?
The motor is basically a small water pump commonly used ...
4
votes
1answer
106 views
making a dc motor sing under load
I have a battery operated toothbrush that I want to generate notes with using PWM on the motor. The microcontroller used is an Arduino for testing and am able to get a bare motor to generate tones. I ...
1
vote
1answer
101 views
TLC59116F (i2c led driver) everything seems ok but LED doesn't work
I'm trying the LED driver TLC59116F with an arduino UNO R3. This IC is a i2c controllable LED driver with PWM and 16 outputs. The registers seem all loaded fine, here's a print of their contents:
...
0
votes
2answers
337 views
15V 3A dc motor PWM frequency setting
What is a suitable frequency for 15V/3A DC motor? Is there any effect on the motor when the frequency is changing? I am confused with this until now and the Internet shows a lot of theory that ...
2
votes
1answer
100 views
Is a low load resistor a big problem in low pass filter and amplifier circuit
I am going to use AVR's PWM output signal to pass through a low pass filter (maybe plus an amplifier). I found the speaker has a quite low resistance (8 ohms). I tried to simulate my schematic on ...
-2
votes
3answers
162 views
How do I calculate the required value for a pull-down resistor in a PWM circuit?
I'm using 74HC595 with SoftPWM to control some LED's.
When the 74HC595 is off, its outputting about 0.57v, enough to turn my LED's on somewhat.
How do I work out the value of the pull-down resistor ...
2
votes
1answer
107 views
PWM & NUD4001 LED driver
Today I tried to build a small circuit which basically consists of three NUD4001 LED driver, three n-Channel FETs and a RGB Power LED from SEOUL. I don't have the exact specs ready but the main specs ...
2
votes
1answer
135 views
Motor control with AVR
I am used to work with PICs, but I want to start using AVRs as well. One thing I like in the PICs is the EPWM (enhanced PWM) peripheral, in which you just set a couple of registers, and the PIC will ...
1
vote
1answer
99 views
AIC1863: How to use this MC to detect the presense of IR transmission?
I have build simple prototype on STM32 ARM Cortex microcontroller trying to understand the usage of AIC1863 IR Preamplifier for Remote Control System (see the handmade PCB on the breadboard).
MCU ...
2
votes
1answer
92 views
PWM drivers of Shift registers that are not open drain?
I am need of a 16 channel PWM Serial based LED driver, or serial in – parallel out shiftregister. I had been looking at TLC5940 and TLC59025 respectively.
But for my current set up the ouptuts ...
2
votes
1answer
63 views
What is the fixed-on interval with regards to stepper motors?
I am using a stepper drive board to control a stepper motor. It has settings for for fixed-on time when using the open-loop PWM control method.
According to the API description:
...
3
votes
3answers
214 views
Square wave -5 to +5 volt at 500 Hz
I need to make a square wave -5 to +5 V at approx. 500 Hz - with small current. I have 0 (ground) and +5 V and a PWM (a Waspmote with a ATmega1281 microcontroller). I think it would be possible to ...
1
vote
1answer
271 views
Arduino alternate PWM input method
I'm working on a rudimentary flight stabilization system for an airplane, which reads in 4 PWM inputs from an R/C receiver. The problem is, the pulseIn command is taking far too long to execute, so I ...
3
votes
3answers
220 views
What is the use of PWM over brushless control
I just saw this question How do I eliminate PWM noise when driving a fan? but cannot think of the reason why is doing PWM over brush-less control useful.
I am assuming people are trying to control ...
6
votes
2answers
381 views
Help with 555PWM motor control
I'm making a laser spirograph for a school project. It requires speed control of three motors. I used a simple 555 astable circuit with a pot for control, then the output goes into the base of a power ...
4
votes
2answers
265 views
Small, cheap, and simple driver for 16 RGB LEDs
I am working on a board design that will put 16 RGB LEDs in a circle around a rotary encoder. I want this setup to be simple so that I can run it from any micro with limited software (ie. built in PWM ...
4
votes
1answer
159 views
How to read a PWM with a separate ground using PIC?
I have a PWM signal that looks like the attached image. It's 12V with pulses of 0V at a 5% duty cycle. The frequency ranges from about 5Hz to about 50Hz. I'm reducing the signal voltage with a simple ...
2
votes
2answers
293 views
Software PWM on a PIC10F202 (looped fading LED)
I'm currently trying my best to code a software solution for PWM on a PIC20F202 but I have one issue. I'm trying a looped fade out and fade with a LED and it's doing fine and very smoothly but on ...
2
votes
4answers
297 views
Picking out correct MOSFET for solenoid PWM control?
I'm attempting to control an automotive solenoid with PWM at 1250hz. At peak, the solenoid draws 3.75 Amps at 14.4 Volts. The specific problem is that any MOSFET that I've tried gets too hot and ...
2
votes
0answers
281 views
Need help with PIC16F887 PWM output
I am trying to get the PWM subsystem on a PIC16F887 working. I've gone over this several times and just cant seem to find my problem.
This is part of a larger program, but for simplicity I re-wrote ...
0
votes
1answer
193 views
ATmega16 Timerr Fast PWM
I tried to set up my ATmega16 timer0 for fast PWM. I uset the code form this page:
ATmega16 Timer Fast PWM
It works, but the explanations on the page are not so good. Why is the dutycycle 25% if i ...
1
vote
3answers
276 views
Scaling PWM amplitude by switching an analog DC voltage?
I'm trying to make a quick-and-dirty voltage-controlled volume control circuit, using a minimal number of components.
A microcontroller is outputting two 5V p-p, 625 kHz PWM signals: an audio ...
5
votes
3answers
232 views
Can LEDs or optocouplers be used without a resistor if PWM is used?
LEDs are often connected through a resistor and the purpose of this seems to be to lower the voltage across the LED to around 1.8V. Can PWM be used to lower the voltage instead of a resistor? If so, ...
0
votes
4answers
355 views
Undervolting PWM fan from 12V to 5V [closed]
What will happen if I feed a 12 Volts rated PWM fan with 5 V driving voltage?
Given all the other variables stay the same (PWM control signals) - will it reduce RPM? By how much?
What happens to the ...
1
vote
1answer
124 views
Correct PWM approach for best brightness
I have a red laser that I like to make it as bright as possible. (Given eye safety regulations) Currently I am pumping Dc current but due to several concerns I like to make the driver pulse width ...
2
votes
2answers
487 views
TL494CN and error amplifier
I'm designing a PWM output for a DC motor and I'm using
TL494CN chip.
It got two error amplifiers and one feedback. I can't understand why there
are error amplifiers and a feedback there? What does ...
1
vote
4answers
319 views
Can I reduce rpm further of a gear motor by using PWM?
I am working on a project where I need to move the object from one point to another in a dead slow speed , The object doesnt weight more than 5 pounds .
I found a DC gear motor with has a RPM of 0.5 ...
2
votes
4answers
572 views
Why is the MOSFET driver in this circuit dying?
This circuit kills the driver (an IR2104s) when under normal conditions.
Bat+ goes to a 12V lead acid battery.
In+ goes to a 20V laptop power supply, though it is intended to be a solar panel ...
1
vote
1answer
178 views
What is a good rule of thumb for practical minimum design duty cycle for a PWM DC motor controller?
I am designing a drive that outputs an RPM of about ~350, with output torque of about ~10 mNm. I found a cheap motor that provides this torque (plus more for insurance), but the speed at rated voltage ...
1
vote
2answers
617 views
Transistor / mosfet for PWM dimming of 30W RGB LED
I am building a led mood light with a high power RGB LED (30W) using 3 constant power supplies for each color.
These are the items I had in mind (but open to suggestions):
30W Integrated RGB LED ...
2
votes
1answer
234 views
PIC18F1320 with 4 separate PWM channels and C18 compiler for an RGB LED
I'm pretty new to microcontroller programming and I find the lack of documentation on certain features of PICs with C18 compiler frustating. I've been trying to make a simple 3-color-led light up ...
