arduino

2946 Articles

Apple II Watch

Strapping An Apple II To Your Body

April 8, 2015 by 20 Comments

Now that the Apple wristwatch is on its way, some people are clamoring with excitement and anticipation. Rather than wait around for the commercial product, Instructables user [Aleator777] decided to build his own wearable Apple watch. His is a bit different though. Rather than look sleek with all kinds of modern features, he decided to build a watch based on the 37-year-old Apple II.

The most obvious thing you’ll notice about this creation is the case. It really does look like something that would have been created in the 70’s or 80’s. The rectangular shape combined with the faded beige plastic case really sells the vintage electronic look. It’s only missing wood paneling. The case also includes the old rainbow-colored Apple logo and a huge (by today’s standards) control knob on the side. The case was designed on a computer and 3D printed. The .stl files are available in the Instructable.

This watch runs on a Teensy 3.1, so it’s a bit faster than its 1977 counterpart. The screen is a 1.8″ TFT LCD display that appears to only be using the color green. This gives the vintage monochromatic look and really sells the 70’s vibe. There is also a SOMO II sound module and speaker to allow audio feedback. The watch does tell time but unfortunately does not run BASIC. The project is open source though, so if you’re up to the challenge then by all means add some more functionality.

As silly as this project is, it really helps to show how far technology has come since the Apple II. In 1977 a wristwatch like this one would have been the stuff of science fiction. In 2015 a single person can build this at their kitchen table using parts ordered from the Internet and a 3D printer. We can’t wait to see what kinds of things people will be making in another 35 years.

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An Apple ][ Emulator On An Arduino Uno

April 8, 2015 by 19 Comments

April Fools’ Day may have passed, but we really had to check the calendar on this hack. [Damian Peckett] has implemented an Apple ][, its 6502 processor, and a cassette port, all on an Arduino Uno. If that wasn’t enough, he also uses a PS/2 keyboard for input and outputs analog VGA. [Damian] is doing all this with very few additional components. A couple of resistors, a capacitor and some very clever hacking were all [Damian] needed to convince an Arduino Uno that it was an Apple.

Making all this work boiled down to a case of resource management. The original Apple ][ had 4KB of RAM and 8KB of ROM. The ATmega328 has only 2KB of RAM, but 32KB of Flash. The only way to make this hack work would be to keep as much of the emulation and other routines in Flash, using as little RAM as possible.

The core of this hack starts with the MOS 6502, the processor used in the Apple. [Damian] wrote a simple assembler which translates the 6502 opcodes and address modes to instructions which can be executed by the Arduino’s ATmega328. To keep everything in ROM and make the emulator portable, [Damian] used two large switch statements. One for address modes, and a 352 line switch statement for the opcodes themselves.

A CPU alone is not an Apple though. [Damian] still needed input, output, and the ROM which made the Apple so special. Input was through a PS/2 keyboard. The PS/2 synchronous serial clock is easy to interface with an Arduino. Output was through a custom VGA implementation, which is a hack all its own. [Damian] used the lowly ATmega16u2 to generate the video timing. The 16u2 is normally used as the Arduino Uno’s USB interface. The only external hardware needed is a single 120 ohm resistor.

The original Apples had cassette and speaker interfaces. So does this emulated Apple. [Woz’s] original cassette and speaker interface accurate loops to generate and measure frequencies. One of the trade-offs [Damian] accepted in his 6502 was cycle accuracy, so he couldn’t use the original routines. Not a problem though, as he was able to write simple functions to replace these routines and drop them in place of the Apple’s own ROM calls.

The Apple ][ ROM itself is handled as one giant character array. This includes the system monitor, Mini-Assembler, Sweet-16, and [Woz’s] own Integer Basic. [Damian] caps off this incredible project by booting his new computer, loading a  Mandelbrot set program from cassette -or in this case an audio file stored on his cell phone, and running it. The well-known fractal is displayed in all its glory on a modern LCD monitor, driven by a microcontroller, emulating a computer from nearly 40 years ago.

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Advanced Not-Reading Technology

April 6, 2015 by 174 Comments

Yesterday, there was a Hackaday post for a Kickstarter campaign. Because we force everyone to read every Hackaday post, there were some complaints and suggestions that we flag posts about Kickstarter campaigns. The most obvious solution to this problem of forcing people to read what they don’t want to read would be a UserScript or browser extension that automatically removes posts with objectionable tags.

It took 12 hours for [Daniel Ward] to lift you up to salvation, ending the inexorable toil you have all suffered under the thumb of idiotic and incompetent Hackaday editors.

[Daniel] wrote a UserScript for GreaseMonkey or TamperMonkey that looks at the tags for each and every Hackaday post. If a tag matches, “crowd-funding”, “crowdfunding”, or “kickstarter”, the post is removed from your browser.

It’s an astonishing advancement in state of the art, “not reading what you don’t want to read” technology. Bards and troubadours will sing of this day for years. Philosophers and theologians are citing this as evidence of something they’re calling, ‘free will.’ We don’t know who [Will] is, but at least he’s free now.

If that’s not enough, [RoGeorge] came up with an astonishing twist on this life-changing technology. By adding, ‘Arduino’ to the blacklisted tags, all posts tagged ‘Arduino’ are also removed. This can, of course, be extended to any tag. Imagine; a world where you don’t have to read what you don’t want to read. A futuristic utopia. Astounding.

High Speed SSD1306 Library

April 3, 2015 by 8 Comments

[Lewin] wrote in to tell us about a high speed library for Arduino Due that he helped develop which allows interfacing OLED displays that use the SSD1306 display controller, using DMA routines for faster display refresh time.

Typically, displays such as the Monochrome 1.3″ 128×64 OLED graphic display , are interfaced with an Arduino board via the SPI or I2C bus. The Adafruit_SSD1306 library written by [Limor Fried] makes it simple to use these displays with a variety of Arduinos, using either software or hardware SPI. With standard settings using hardware SPI, calls to display() take about 2ms on the Due.

[Lewin] wanted to make it faster, and the SAM3X8E on the Due seemed like it could deliver. He first did a search to find out if this was already done, but came up blank. He did find [Marek Buriak]’s library for ILI9341-based TFT screens. [Marek] used code from [William Greiman], who developed SD card libraries for the Arduino. [William] had taken advantage of the SAM3X8E’s DMA capabilities to enable faster SD card transfers, and [Marek] then adapted this code to allow faster writes to ILI9341-based screens. All [Lewin] had to do was to find the code that sent a buffer out over SPI using DMA in Marek’s code, and adapt that to the Adafruit library for the SSD1306.

There is a caveat though: using this library will likely cause trouble if you are also using SPI to interface to other hardware, since the regular SPI.h library will no longer work in tandem with [Lewin]’s library. He offers some tips on how to overcome these issues, and would welcome any feedback or testing to help improve the code. The speed improvement is substantial. Up to 4 times quicker using standard SPI clock, or 8 times if you increase SPI clock speed. The code is available on his Github repo.

Temperature, Altitude, Pressure Display

April 1, 2015 by 11 Comments

During a recent trip to Bhutan, [electronut] wished for a device that would show the temperature and altitude at the various places he visited in the Kingdom. Back home after his trip, he built this simple Temperature, Altitude and Pressure Display Device using a few off the shelf parts.

Following a brief search, he zeroed in on the BMP 180 sensor which can measure temperature and pressure, and which is available in a break-out board format from many sources. He calculates altitude based on pressure. The main parts are an Arduino Pro Mini clone, a BMP180 sensor and a Nokia 5110 LCD module. A standard 9V battery supplies juice to the device. A push button interface allows him to read the current parameters when pressed, thus conserving battery life.

Standard libraries allow him to interface the LCD and sensor easily to the Arduino. He wrapped it all up by enclosing the hardware in a custom laser cut acrylic box. The result is bigger than he would like it to be, so maybe the next iteration would use a custom PCB and a LiPo battery to shrink it in size. While at it, we think it would be nice to add a RTC and some sort of logging capability to the device so it can store data for future analysis. The schematic, code and enclosure drawing are available via his Github repository.

Chinese Whispers For Arduino

March 30, 2015 by 33 Comments

The game of Chinese Whispers or Telephone involves telling one person a sentence, having that person tell another person the same sentence, and continuing on until purple monkey dishwasher. For this year’s Arduino Day, [Mastro] was hanging out at Crunchlab with a bunch of Arduinos. What do you do with a bunch of Arduinos? Telephone with software serial.

The setup for this game is extremely simple – have one Arduino act as the master, listening for bits on the (hardware) serial port. This Arduino then sends those bits down a chain of Arduinos over the software serial port until it finally loops around to the master. The result is displayed in a terminal.

With only about a dozen Arduinos in this game of Telephone, [Mastro] did get a few transmission errors. That’s slightly surprising, as the code is only running at 1200 bps, but the point of this game isn’t to be completely accurate.

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Arduino IDE Support For The ESP8266

March 28, 2015 by 64 Comments

Despite a wealth of tutorials for setting up and writing code for the ESP8266 WiFi module, there has not been much of anything on programming this cheap wireless module with the Arduino IDE. Finally, this has changed. After many months of coding, the Arduino IDE supports the ESP8266 module.

The Arduino IDE support was announced on the ESP8266 community forum. Setup is fairly simple with downloads for Linux, OS X, and Windows. This isn’t an ESP8266 shield, either: you can write code for the ESP module, connect the serial pins, and hit the program button.

The basic functions of the Arduino IDE – pinMode, digitalRead, digitalWrite, and analogRead – are available. Most of the WiFi functions work just like the WiFi shield library.

There are a few things that aren’t written yet; PWM doesn’t work, as the ESP8266 only has one hardware PWM source. SPI and I2C slave mode aren’t done yet, and uploading sketches via WiFi needs a little bit of thought. That said, this is a great introduction to programming the ESP module. If the Arduino IDE isn’t your thing, you could always do it the cool way with [CNLohr]’s programming tutorial we featured last week.