Microcontrollers

2355 Articles

ARM Programming On Mars

September 10, 2015 by 39 Comments

Before you overreact to the title, keep in mind the latest version of Eclipse is code named “Mars.” It is always a bit of a challenge to set up a generic ARM tool chain. If you don’t mind sticking to one vendor, shelling out a lot of money, or using Web-based tools, then you might not have this problem. But getting all the tools together can be annoying, at best.

[Erich Styger] works with students and knows they often stumble on just this step so he’s provided clear documentation for getting Eclipse, the ARM gcc compiler, and a full set of tools installed. He focuses on Windows and the Kinetis platform, but the steps are virtually the same regardless. Just get the right tools for your operating system and skip the Kinetis-specific parts if you don’t need them.

Continue reading “ARM Programming On Mars” →

Pulse Density Modulation

September 8, 2015 by 34 Comments

[esot.eric] was trying to drive a motor and naturally thought of using pulse width modulation (PWM) to control the motor speed. However, he found that even with a large capacitor, his underpowered power supply would droop before the PWM cycles were complete. So instead of PWM he decided to experiment with pulse density modulation.

The idea is to use smaller pulses over a longer period of time and make the average power equal to the percentage motor speed desired. With a PWM system, for example, if the time period is T, a 50% PWM drive would have the  drive high for T/2 and low for the other half of the cycle. With pulse density, each pulse might be T/10 (as an example) and then the output would be on for 1/10, off for 1/10, on for 1/10 and so on, until by time T you’d still get to 50%. The advantage is the output capacitor gets a kick more often and has less opportunity to droop.

Continue reading “Pulse Density Modulation” →

Embed With Elliot: Practical State Machines

September 4, 2015 by 41 Comments

Raindrops on roses, and whiskers on kittens. They’re ok, but state machines are absolutely on our short list of favorite things.

There are probably as many ways to implement a state machine as there are programmers. These range from the terribly complex, one-size-fits-all frameworks down to simply writing a single switch...case block. The frameworks end up being a little bit of a black box, especially if you’re just starting out, while the switch...case versions are very easy to grok, but they don’t really help you write clear, structured code.

In this extra-long edition of Embed with Elliot, we’ll try to bridge the middle ground, demonstrating a couple of state machines with an emphasis on practical coding. We’ll work through a couple of examples of the different ways that they can be implemented in code. Along the way, we’ll Goldilocks solution for a particular application I had, controlling a popcorn popper that had been hacked into a coffee roaster. Hope you enjoy.

Continue reading “Embed With Elliot: Practical State Machines” →

Stuffing Everything On A DIP32 Package

August 30, 2015 by 9 Comments

Putting an full microcontroller platform in a DIP format is nothing new – the Teensy does it, the Arduino nano does it, and a dozen other boards do it. [Alex] and [Alexey] aren’t content with just a simple microcontroller breakout board so they’re adding a radio, an OLED, an SD card reader, and even more RAM to the basic Arduino platform, all in a small, easy to use package.

The DIPDuino, as [Alex] and [Alexy] are calling it features an ATmega1284 processor. To this, they’re adding a 128×32 pixel OLED, a micro SD slot, and 1Mbit of SRAM. The microcontroller is a variant that includes a 2.4 GHz Zigbee radio that allows for wireless connections to other DIPDuinos.

What are [Alex] and [Alexey] going to do with their cool little board? They’re planning on using the OLED for a watch, improve their software so the firmware can be updated from the SD card, and one of [Alex]’s friends wants to build a RepRap controller with one of these. There’s a lot of potential with this board, and we’re interested in seeing where the guys take the project from here.

Wii MotionPlus Gyro To Microchip PIC

August 29, 2015 by 3 Comments

Sometimes the most mundane products have surprisingly sophisticated internals. What’s in a game controller? If it is a Wii remote, you’ll find a lot inside–an IR sensor, Bluetooth, an accelerometer, and EEPROM. It also has a six pin expansion port that allows I2C peripherals connect to the controller.

[DotMusclera] wanted to experiment with a gyroscope and decided to hook up to the Wii MotionPlus to a Microchip PIC. Using information from the WiiBrew wiki, [DotMusclera] connected a PIC18F4550, an LCD, and a handful of components (mostly to do 3.3V level conversion), he set up the hardware on a breadboard. The only odd part you might have to work around is a Wii breakout board that converts from the breadboard to the Wii interface.

The software is easy to follow since it is written in Hi-TECH C and well-commented. The hardware lacks a schematic, but from the parts list and the video, you can probably figure it out. The setup works well and shows roll, pitch, and yaw on the LCD screen.

The project log is very detailed, with a lot of information about gyroscopes and the communication format the gyro uses. The video demo is worth watching as well.

Continue reading “Wii MotionPlus Gyro To Microchip PIC” →

Before Arduino There Was Basic Stamp: A Classic Teardown

August 27, 2015 by 122 Comments

Microcontrollers existed before the Arduino, and a device that anyone could program and blink an LED existed before the first Maker Faire. This might come as a surprise to some, but for others PICs and 68HC11s will remain as the first popular microcontrollers, found in everything from toys to microwave ovens.

Arduino can’t even claim its prominence as the first user-friendly microcontroller development board. This title goes to the humble Basic Stamp, a four-component board that was introduced in the early 1990s. I recently managed to get my hands on an original Basic Stamp kit. This is the teardown and introduction to the first user friendly microcontroller development boards. Consider it a walk down memory lane, showing us how far the hobbyist electronics market has come in the past twenty year, and also an insight in how far we have left to go.

Continue reading “Before Arduino There Was Basic Stamp: A Classic Teardown” →

ESP8266 In Commercial Products

August 25, 2015 by 26 Comments

The hobbyist electronics market is still tiny, and even though random companies are coming out with some very interesting hardware, these parts and components aren’t exactly meant for us. The ESP8266 WiFi module is a slight deviation from this trend, with hundreds of different ESP dev boards floating around, and weirdos buying them by the bag.

[4ndreas] finally found the ESP8266 in a product; it’s not a very noteworthy observation until you realize how much work has gone into the development of open source toolchains for the ESP.

[4ndreas] found an RGB LED strip on Ali Express that could be controlled by WiFi. Inside, he found everyone’s favorite WiFi module, and by shorting two pins, he started up the controller in bootloader mode.

Because of the massive amount of open source development surrounding the ESP8266, there are a host of tools that can be used to program this cheap LED controller. [4ndreas] took a swing at writing his own firmware for the controller and came up with this project.

It’s not a killer project, but it does demonstrate the power of open source toolchains for cheap WiFi modules. This is only the first product found with an ESP8266 inside, but there are undoubtedly others out there just waiting to be taken apart and controlled in more advanced ways.

Continue reading “ESP8266 In Commercial Products” →