How to build your own linear adjustable power supply based on LM317. In this tutorial I’ll explain how linear power supply works, what parts it consists of and a lot of small details, like how to calculate smoothing capacitor value, or how to choose a transformer. Plus you’ll see how to build an actual power supply.
LM317 Simple Adjustable Linear Power Supply - [Link]
Few month ago I wanted to try to write software for Microchip PIC16F883 microcontroller and I couldn’t find simple development board for it. And so I made my own.
It took me a couple of hours to design the board in Eagle and a couple more hours to make it with toner transfer method and solder it.
This development board is as simple as it gets. Just PIC16F883 controller in SO28W package, linear regulator with two selectable voltages 3.3V and 5V. Bunch of pinheaders connected straight to the MCU I/O pins, pinheaders for VCC and GND, and programming port.
PIC16F883 Development Board - [Link]
In this video I’ll tell you what is darlington transistors, how to use them to switch medium current loads with microcontroller and what downsides they have.
Also you’ll find out about darlington arrays. Of course there would be small demonstration of controlling different loads at the end of this video.
Interfacing Microcontroller: Darlington Transistors - [Link]
In this article I will tell you how to get shorter relay switching times and how to minimize relay current consumption. The same exact things apply to solenoids and solenoid valves.
You need to use a transistor because either relay you want to control needs a higher voltage than your microcontroller can provide, or relay’s current demand is too high. Although some microcontrollers can give enough current to switch a relay, but most of them is incapable of doing that.
And the diode in parallel with relay coil (or solenoid coil) is needed to suppress the flyback voltage that occurs when transistor is switching-off and magnetic field stored in coil collapses. That flyback voltage can reach hundreds of volts, which can completely destroy the driving transistor.
Using Relays (Tips & Tricks) - [Link]
My parents growing their own organic food and they asked me to deal with winter temperatures problem in the storage room. It gets really cold here, in Ukraine. Some winters have even lower temperatures than -30°C (-22°F). So right now I designing a simple thermostat for keeping temperature at about 5-7 degrees C above zero. Plus right now I started to use my garage as a gym, so this thermostat would be handy there too.
It’s based around ATMEL AVR ATtiny2313 microcontroller, it will measure temperature using DS18B20 digital temperature sensor, and it has a 30A 240VAC relay to control heater.
Well, basically break beam sensor consists of two parts: transmitter and receiver. Transmitter emits light (it could be, for example, an LED or a laser) and that light goes to receiver. If that light beam between transmitter and receiver is broken by some obstacle, and receiver detects no incoming light even for a brief moment – it triggers an alarm (or any load you want). For example you can count people that entering some room, or you can use it as an alarm system, yeah, just like in movies!
First thing that comes to mind is to connect LED or laser to DC power supply on transmitter side, and use phototransistor with an amplifier on receiver side. But that is not gonna work with changing ambient light level. For example you calibrated your amplifier to work on a cloudy day, and then bright sun shined at it and in this case it won’t trigger an alarm because it already has sufficient level of incoming light.
Break-Beam Sensor - [Link]
Very often when designing some stuff I need a square wave signal generator with variable pulse width and frequency to control power MOSFETS.
You can use such a tool when designing DC-DC converter or switch-mode power supply, you can use it to emulate PWM from microcontroller when developing some new embedded design, or maybe you want to design your own wireless charger… This is only some of the things you can use it for.
PWM Generator Project - [Link]
Very often in electronics you would need to measure temperature, not just in one spot, but simultaneously in two or more spots. And log that measurements, so that you can plot temperature change over time.
Also, differential temperature measurements could be extremely useful in some cases, especially for thermal design of electronic projects.
So, the other day I bought this UNI-T UT325 dual-channel logging thermometer for a little under $80.
UNI-T UT325 Thermometer Review - [Link]
More and more experiments are now ‘PC-assisted.’ Also conventional acquisition systems are very expensive. Since portable PCs are today common and a USB link is a better solutionhere we present an oscilloscope using USB port of the PC that operates at up to 10 kHz with ±16V input voltage. It has much more improved features than the PC-based oscilloscope . The oscilloscope uses IC PIC18F2550 from Microchip as the main controller, which makes the oscilloscope compact as there is no need of additional power supply for the entire circuit board.
Two-Channel PC Based Oscilloscope USB - [Link]
dangerousprototypes.com writes: [via]
If you’re at that stage as a beginner where you wonder what’s going on behind the scenes on an Arduino board you should check out jumperone’s tutorial on using microcontrollers. There you’ll learn what’s needed to take a bare microcontroller and load your own program onto it. Both PIC and Atmel chips are covered, with an explanation of what simple components you need to get started in addition to the chip itself, along with programming connections and hardware.
Microcontrollers for newbies - [Link]