by MakerSpark Industries @ instructables.com:
This Instructable is about how to create an Arduino PIR motion sensor for your room or office, using parts available from your local Radio Shack! Whether you’re looking for a cool and easy-to-build security sensor, or an awesome first project to dive into the world of Arduino, Microcontrollers, and electronics, this project is for you. (This project really is easy. Take it from me, I’m 12, and I’ve only had my Arduino for a week and a half.)
Arduino PIR Motion Sensor - [Link]
Everytime we need to test a stepper motor controller we have to connect it to the parallel port of the computer or to a function generator to obtain the necessary pulses the realize the movements of the stepper.
This is a quicker method to check a controller integrity. Simply to make the life easier here is a square wave signals generator. A potentiometer or a trimmer regulates the pulse generation of the 12F675 microchip (a square wave, between 20 hz and 3khz). Ok, there are thousands of different ways to create a pulse generator, but we had a lot of microcontrollers.
12F675 pulse generator - [Link]
The ULN2003A 7-way (or ULN2803A 8-way) darlington driver is usually the go-to chip of choice when you need to switch any high current load from a microcontroller’s GPIO. It provides seven darlington driver stages to give low-side switching and even includes seven common-cathode clamp diodes to snub voltage spikes when high inductance loads are used. Texas instruments have recently introduced an alternative device which is said to be the industry’s first seven-channel, NMOS low-side driver chip.
The TPL7407L is a high-current NMOS transistor array. It contains seven NMOS transistors that feature high-voltage outputs also with built-in clamp diodes. The input stage is compatible with GPIO logic levels ranging from 1.8 to 5.0 V and the maximum rating of each NMOS channel is 600 mA. Several outputs can be paralleled if it is necessary to sink higher levels of load current. The TPL7407L’s key benefit is its improved power efficiency and lower leakage compared to bipolar darlington drivers.
Efficient NMOS Driver Array - [Link]
Dan over at HackAday documented his single chip computer project with the PCBs from DirtyPCBs:
A single AVR microcontroller (the ATmega 1284P) has been used to create a standalone computer system which runs the BASIC programming language. The 1284P runs TinyBASIC Plus, generates RCA video signals (using TVout) and reads PS/2 keyboard input. A single sided PCB was used to hold all the components meaning it is easy to manufacture the computer at home using processes such as photo-etching. Additionally, the component count is fairly low and only one IC is required (the 1284P).
Single chip AVR BASIC computer - [Link]
Michael Dunn @ edn.com writes:
Whether engineer, hobbyist, or maker, we’ve happily watched as chipmakers and third parties alike have come to their senses in recent years and cooked up a smorgasbord (smorgasboard?) of low-cost microcontroller devboards – in some cases, very low cost, like TI’s $4.30 MSP430 board. More recently, we’ve seen ARM Cortex kits for $10-$50, the flowering of the whole Arduino ecosystem, and of course, the Raspberry Pi, starting at $25. It’s microcontroller heaven.
Those of us wanting a cheap “in” to the FPGA world have been less lucky. But the times, they are a changin’. Many FPGA devkits, from both chipmakers and third parties, have broken – or downright shattered – the $100 barrier, opening the door to low-cost FPGA prototyping, education, hobby projects, and so on.
Follow me as I explore this brave new world of affordable FPGA learning and design. I’ve acquired a representative selection of bargain-priced boards, and will be reviewing each, not just on paper, but by actually creating projects with it.
FPGA boards under $100: Introduction - [Link]
By Jon Gabay @ digikey.com:
Copper-based connectivity has served us well for a long time and will continue to do so in applications where it is effective from a performance and cost perspective. For very-high speed and/or long-distance signaling, however, the material cost and physical signal limitations of using metallic conductors has driven eyes to other transport mechanisms.
Fiber optics is not new, and the telecom industry has pushed development and deployment of fiber-optic transceivers and links so that they now span the globe. Very few of our designs have had the need to traverse long distances at such high speeds. Even fewer of us have had deep enough pockets to set up vast high-speed networks. On the other hand, engineers now are finding that local requirements are pushing the limits of metallic interconnects.
Microcontrollers and Fiber Optics - [Link]
An SMPS application using PIC16F785 from Microchip. [via]
In this application note, we will examine a typical buck topology intelligent SMPS design using the PIC16F785.
The design presented here shows an alternative single-chip approach to adding intelligence to SMPS designs. The basic design is really unchanged. There are current and voltage feedback loops, a counter-based PWM is used to generate the reference voltage to the voltage loop, and the microcontroller uses the reference voltage to modify the operation of the system in response to conditions sensed through the ADC.
App note: Switching power supply design with the PIC16F785 - [Link]
Arthur Guy made this mini LCD backpack for the smaller display screens:
This is an LCD backpack but it is for the smaller displays with the double row of pins rather than the single line.
I made this adapter as I was working with some small displays and needed a simple way of connecting it to a microcontroller. There are plenty of adapters for the standard single row displays but I couldn’t find any for the smaller dual row displays
This adapter works with existing libraries built around the PCF8754 shift register
Mini LCD Adapter Backpack - [Link]
By Jon Gabay:
To do something useful, a microcontroller (MCU) must be connected to other devices. This connection is made through input/output (I/O) pins. More times than not, these days pins are multifunctional and can connect to A/Ds, D/As, linear functions (such as op amps and comparators), voltage references, and more. So for the design engineer, protecting these I/Os against potentially damaging static charges and other similar threats is of high importance.
In establishing proper protection for an MCU, engineers are finding that characteristics they have depended on for years have suddenly become less effective and they are forced to revisit problems of the past. Why? Principally, as a result of market pressure to reduce the cost of their products, semiconductor manufacturers have combined a higher level of integration with continued shrinking of process geometry, making die sizes smaller. As a result, implementing the necessary transient immunity protection to prevent malfunction due to transients on power and signal lines has become increasingly difficult.
Protecting MCU I/O Lines from ESD and Other Transients - [Link]
by Benabadji Noureddine:
This Design Idea demonstrates a new method of driving six LEDs with only two I/O lines from a microcontroller, and so is particularly suitable for any pin-limited chip. It uses a pair of I/O lines combined with a pair of complementary bipolar transistors. More than one LED can appear to be lit by multiplexing.
Two PIC pins drive six LEDs - [Link]