September 12, 2013 /
Matseng put together a nifty tool that can quickly identify both the transistor type, and the correct pin out. We posted a method earlier on how to determine these characteristics manually, but where’s the fun in that ? Part of his self set goal of making a Project A Week, this is his 22nd week project.
His design uses a PIC16LF1503 microcontroller and is powered by a CR2032 coin cell battery. It uses LEDs and silk-screen markings to show you the output. On the PCB there are holes for common transistor configurations such as to-92, to-18 and to-220 that you can insert to be identified. The part is given a voltage in different configurations and read back using the PIC’s ADC.
Source code and schematic are provided on his post to the Dangerous Prototype’s forums.
August 27, 2013 /
Isn’t it fun to take stuff apart and see how things are made ? Well Michael over at EDN likes to as well! He’s got one of those cheap-y eBay Bluetooth OBD-II adapters and while what’s inside isn’t much of a shocker, it’s still nice to look at how things are made.
Inside is a bunch of power regulation, a CAN bus transceiver, a Microchip PIC and a ready-made bluetooth module. Usually when you crack these cheap clones apart the soldering looks pretty shoddy, but this one looks pretty clean except for the Bluetooth module for some reason.
Check out the full teardown.
August 26, 2013 /
You have probably seen those little dongles that let people swipe their credit card on their smart phone or tablet. These little dongles transmit data to the device via the microphone jack. The audio recorded is then examined and the data is either a one or a zero.
In the example described by the article, they are using a PIC and the data is encoded via manchester encoding. A resistor and a pot are used to tweak the output level. This is a great way to send data to a smart phone or tablet without making any crazy custom dongles but you are limited in capabilities.
Schematic and example source code is included in the post.
August 12, 2013 /
On the 20 some-odd remotes I have around the house, I know there are a bunch of buttons on some of them that don’t do anything for my model of whatever it controls. Badr noticed the same thing on his satellite receiver. So he decided to give those extra buttons something to control.
Armed with a little IR transmission know-how, a 16f84a, a transistor array and some relays he added support for controlling his some lights and a fan.
He’s got a schematic and source code up here.
July 27, 2013 /
I’m always a big fan of learning more about Why vs How . Once you understand what’s really happening inside the black box, you can interface with it better after you really know its needs. Siddharth is here to school you and teach you more about stepper motors. If you’re thinking about building things like robotic arms, or 3D printers you’ll most likely use a stepper motor. DC motors are good for most things, but stepper motors allow you to get accurate with your precise location while giving you lots of power at the same time.
This is one of those articles you need to bookmark for later when you are actually working on something using steppers. The diagrams showing the differences between 4/5/6 and 8 wire configurations, and Full step, half step and microstepping are going to be valuable to refer back to. I sware every time I hook up a 6 wire stepper to a 4 wire controller I have to google it each time.
Siddharth also has a follow-up article where he interfaces the stepper to a PIC microcontroller.