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]
Here’s an interesting project by Steve of Tangent Audio the AZIZ project, a microcontroller-based LED microscope illuminator:
AZIZ is an LED microscope illuminator that I designed and built from scratch. It is designed around a Texas Instruments TLC59116 constant-current PWM LED driver chip, and an Atmel ATTiny1634 8-bit microcontroller.
AZIZ: DIY LED microscope illuminator - [Link]
Publitek European Editors writes:
Many security and motion detector systems rely on small, semi-autonomous nodes that are easy and simple to install. This implies the use of a battery-based power source and low-power operation in order to minimize the number of battery changes during the lifetime of the product.
Over its lifetime, the output voltage of a battery falls, with the biggest decline when the charge is nearing full depletion. A converter type that can accommodate this change in voltage but can still provide relatively high voltages for sensors and RF transmitters is the buck-boost converter – it operates the buck part of the circuit when the battery is fresh, moving to boost operation when the voltage falls below the threshold of the electronic circuitry it powers. A number of vendors have developed integrated buck-boost converters optimized for battery systems
Buck-Boost Converters Help Extend Battery Life for Motion Detection - [Link]
Zak Kemble build an AVR based PWM fan controller. He writes:
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 like the previous controllers. I used ATtiny25 controllers running at 31.25KHz (8MHz internal RC / 256 prescaler) with a 3.3V supply, the MOSFETs I used are STP36NF06L with 0.045Rds and 2.5Vgs max, perfect for 3.3V, the MOSFETs only generate ~180mW of heat at 2A ((0.045Rds * (2A * 2)) = 0.18W) so no heatsink needed, you can barely feel them getting warm.
AVR microcontroller based PWM fan controller - [Link]
Macroblock MBI5030, 16-ch constant current LED driver with PWM, SPI-like interface, requires external e clock.
The problem: you need the chip to figure out if your code actually works. And you also need the LEDs to see what’s going on – if at all. You could use a logic analyzer, but that is overkill. Just looking at the LEDs is a much more suitable way. Your code might have insidious bugs, or the datasheet might simply be crap / outdated / obsolete – of course without your knowledge. BUT you surely don’t want to fight wires, at least not during the coding / debugging phase. All you need is the chip + onboard LEDs as indicators.
MBI5030 – 16ch LED constant current LED driver starter board - [Link]