Experience the “Farmer’s Market” of Vintage Electronics

Normally when you think of a Farmer’s Market, fresh produce grown nearby comes to mind. This experience was similar in that much of the produce was conceived locally, but the goal is to be anything but fresh. I had the opportunity last weekend to attend the final Electronics Flea Market of 2014. I can’t speak for everyone, but there is an obvious affinity for vintage electronics equipment in just about any condition. The people you run into are as interesting as the equipment being swapped, and the social outing tends to continue even after the swap meet closes.

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A Proof of Concept Project for the ESP8266

It’s hardly been a month since we first heard of the impossibly cheap WiFi adapter for micros, the ESP8266. Since then orders have slowly been flowing out of ports in China and onto the workbenches of tinkerers around the world. Finally, we have a working project using this module. It might only be a display to show the current weather conditions, but it’s a start, and only a hint of what this module can do.

Since the ESP8266 found its way into the storefronts of the usual distributors, a lot of effort has gone into translating the datasheets both on hackaday.io and the nurdspace wiki. The module does respond to simple AT commands, and with the right bit of code it’s possible to pull a few bits of data off of the Internet.

The code requests data from openweathermap.org and displays the current temperature, pressure, and humidity on a small TFT display. The entire thing is powered by just an Arduino, so for anyone wanting a cheap way to put an Arduino project on the Internet, there ‘ya go.

Build Your Own Retrocomputer with Modern Chips

If you’ve ever wanted to get started in retrocomputing, or maybe the Commodore 64 you’ve been using since the 80s just gave up the ghost, [Rick] aka [Mindrobots] has just the thing for you: a retrocomputer based on a PIC microcontroller and a Parallax Propeller.

The two chips at the heart of the computer are both open source. The Propeller is the perfect board to take care of the I/O, video, and audio outputs because it was purpose-built to be a multitasking machine. The microcontroller is either a PIC32MX150 or a PIC32MX170 and is loaded with a BASIC interpreter, 19 I/O pins, a full-screen editor, and a number of communications protocols. In short, everything you would ever want out of a retro-style minicomputer.

The whole computer can be assembled on a PCB with all the outputs you can imagine (VGA, PS/2, etc) and, once complete, can be programmed to run any program imaginable including games. And, of course, it can act as a link to any physical devices with all of its I/O because its heart is a microcontroller.

Retrocomputing is quite an active arena for hackers, with some being made from FPGAs and other barebones computers being made on only three chips. It’s good to see another great computer in the lineup, especially one that uses open chips like the Propeller and the PIC.

Afroman Demonstrates Boost Converters

If you need to regulate your power input down to a reasonable voltage for a project, you reach for a switching regulator, or failing that, an inefficient linear regulator. What if you need to boost the voltage inside a project? It’s boost converter time, and Afrotechmods is here to show you how they work.

In its simplest form, a boost converter can be built from only an inductor, a diode, a capacitor, and a transistor. By switching the transistor on and off with varying duty cycles, energy is stored in the inductor, and then sent straight to the capacitor. Calculating the values for the duty cycle, frequency, inductor, and the other various parts of a boost converter means a whole bunch of math, but following the recommended layout in the datasheets for boost and switching converters is generally good enough.

boostconverter

[Afroman]’s example circuit for this tutorial is a simple boost converter built around an LT1370 switching regulator. In addition to that there’s also a small regulator, diode, a few big caps and resistors, and a pot for the feedback pin. This is all you need to build a simple boost converter, and the pot tied to the feedback pin varies the duty cycle of the regulator, changing the output voltage.

It’s an extremely efficient way to boost voltage, measured by [Afroman] at over 80%. It’s also exceptionally easy to build, with just a handful of parts soldered directly onto a piece of perfboard.

Video below.

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A Breakout Board for a Flir Lepton

Thermal imaging cameras are all the rage now, and one of the best IR cameras out there is Flir’s Lepton module. It’s the sensor in the FLIR ONE, a thermal imaging camera add-on for an iPhone. Somewhat surprisingly, Flir is allowing anyone to purchase this module, and that means a whole bunch of robotics and other various electronics projects. Here’s a breakout board for Flir’s Lepton.

Electron artisan [Mike] recently got his hands on a FLIR ONE, and doing what he does best, ripped the thing apart and built the world’s smallest thermal imaging camera. Compared to professional models, the resolution isn’t that great, but this module only costs about $250. Just try to find a higher resolution thermal imager that’s cheaper.

With this breakout board, you’ll obviously need a Lepton module. There’s a group buy going on right now, with each module costing just under $260.

The Lepton module is controlled over I2C, but the process of actually grabbing images happens over SPI. The images are a bit too large to be processed with all but the beefiest Arduinos, but if you’re thinking of making Predator vision with a Raspi, BeagleBone, or a larger ARM board, this is just the ticket.

You can check out some video made with the Lepton module below.

This is also project number 3000 on hackaday.io. That’s pretty cool and worthy of mention.

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Hands On with the Intel Edison

Yesterday the tech world resounded with the astonishing news that Apple can’t run a CMS, rotary encoders were invented just for the Apple Watch, and Intel’s Developer Forum was scheduled well in advance of the Apple media circus. Intel’s smallest computer yet, the Edison, was also announced. Very few people without an Intel employee badge have one of these cool little devices, and lucky for us one of them put up a hands-on review.

With a lot of comments asking what the Edison is good for, [Dimitri] tells us the Edison isn’t meant to be only a dev board. A better comparison would be something like the Raspberry Pi compute module – a small board that product designers can build a device around. This, of course, is not news and should come as a surprise to no one. The 70-pin connector used in the Edison isn’t rated for high-frequency insertions, anyway.

Stock up on level shifters

Compared to even a Raspberry Pi, or even an Arduino Mega, the Arduino breakout board for the Edison is huge. The reason for this is a huge number of level shifters. Where Arduinos can chug right along at 3.3V and 5V, and a Pi uses the somewhat more uncommon (at least for the hobbyist market) 3.3V logic, most of the Edison runs at 1.8V.  All the user-configurable pins on the smaller breakout are 1.8V logic. Someone reading this will fry their Edison, so don’t say we didn’t warn you.

Performance

[Dimitri] was keen to get an idea of how powerful the Edison is. There’s a pretty good chip in there – an Atom Z34XX – that’s underclocked at 500MHz. Still, despite this apparent performance limitation, a few benchmarks reveal the Edison can work at up to 615 MIPS. That’s about twice the performance of the Raspberry Pi B+, and real-world tests of doing FFT along with OpenCV tracking makes [Dimitri] happy. Power consumption? At a medium load, the Edison draws about 200 mA. A lot of number crunching and blasting bits out of the radios increases that to a maximum of 500 mA. Not exactly low power, but very good in terms of performance per Watt.

Wireless

There are two radios on the Edison, one for Bluetooth Low Energy, and another for a/b/g/n WiFi (yes, it supports access mode). The on-chip antenna is acceptable, but for sending signals to the conference room down the hall, you might want to connect an external antenna.

Linux, Programming, and Arduino

Linux on the Edison isn’t a friendly Debian-derived installation like the Raspberry Pi. Instead, Intel is using Yocto, specifically designed for embedded environments. It’s not quite a distribution but instead a build system. There is no apt-get. Right now, this might be seen as a limitation, but enterprising kernel wizards have ported Debian to the Intel Galileo. Full Linux support is coming, but probably not (officially) from Intel.

Edison launched with an Arduino breakout board, but the Arduino compatibility is literally only a facade. Intel reengineered the Arduino IDE so it writes files instead of toggling pins. This means any programming language that can write a file is able to blink a LED with an Edison. It’s only a matter of preference, but if your idea of embedded development is a single chip and a C compiler, you’re better off using an ATMega and a UART.

Closing thoughts

This isn’t a Raspi killer, a Beaglebone killer, a TI CC3200 killer, or an ESP8266 killer. It’s an x86 board, with WiFi, Bluetooth and Linux that can toggle a few pins. It’s something different. Different is good. That means there are more choices.

A Detailed Look at the 7805 Voltage Regulator

We’re quite sure that all hobbyists have used the 7805 voltage regulator at least once in their lives. They are a simple way to regulate 7V+ voltages to the 5V that some of our low power projects need. [Ken Shirriff] wrote an amazingly detailed article about its theory of operation and implementation in the silicon world.

As you may see in the picture above such a regulator is composed of very different elements: transistors, resistors, capacitors and diodes, all of them integrated in the die. [Ken] provides the necessary clues for us to recognize them and then explains how the 7805 can have a stable output even when its temperature changes. This is done by using a bandgap reference in which the difference between transistor base-emitter voltages for high and low current is used to counter the effects of temperature. As some elements looked a bit odd during [Ken]’s reverse engineering process, he finally concluded that what he purchased on Ebay may be a counterfeit (read this Reddit comment for another opinion).