Cheap and Simple WiFi with ESP8266 for the FRDM Board

How cool would it be to add WiFi support to any projects or IoT? Why not using WiFi with a microcontroller which has only few KBytes of RAM and FLASH. For less than US$5? Dreams came true, and intrigued by an article at Hack-A-Day, I searched a supplier for that ESP8266 module. And this evening I have found the four ESP8266 modules I have ordered for $4.50 each from ElectroDragon in my mailbox. Of course I did not want to wait for the week-end, so I hooked it up to my FRDM-KL25Z board.

ESP8266 Module

ESP8266 Module for US$ 4.50

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User Interrupt on NMI Pin with Kinetis and ExtInt Component

While my beef brisket (see “My First DIY Smoked Beef Brisket: Day 1“) is smoking on ;-), I have time to investigate a problem I was running on in my lecture on Friday: For the Joystick shield (see “JoyStick Shield with the FRDM Board“) on the FRDM-KL25Z board, I wanted to use an interrupt if I press the green button:

No Interrupts for Button C

No Interrupts for Button C

However, that did not work :-(.

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BBQ Smoker Monitoring Robot

I have to admit: I’m not a vegetarian. I love BBQ, and no offense to vegetarians! Today is perfect day for another BBQ session, and this time I plan to enhance it with electronics. No, not eating electronics, but doing BBQ with a little DIY electronic helper. There are different ways to cook meat on an open fire pit, and each region of the world has its own way to do it. Traditionally, in my area we are ‘grilling’ the meat: high temperature, for a few minutes, done! I like that ‘fast food way’ too, but there is an even better version: Slow food smoking!

I’m gifted that I had the opportunity to experience the Texas BBQ culture: slowly cooking the meat, at low temperature, and ‘smoking’ it: Cooking the meat around 80°C prevents that it gets dry (because the water does not vaporize, see this article on Wikipedia). There are different ways how to do this, but I love the way how it is done at the Salt Lick in Austin/TX with an open fire pit:

BBQ Pit in Austin Texas

BBQ Pit in Austin Texas

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LED Clock with Kitchen Hot Pan Protector

When I showed my 60 NeoPixel LED clock prototype to my daughter and her girlfriend, and they both wanted to have one right away :-). Well, that clock was just a proof of concept, with lots of temporary wiring. So I decided this week-end to beautify it and to make it look nice and clean(er). There is nothing like a week-end project with adding a few more LEDs and features :-).

Adafruit Neopixel Clock with 60+24+12 LEDs

Adafruit Neopixel Clock with 60+24+12 LEDs

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Adafruit NeoPixel Clock with 60 LEDs

After the problems with level shifters (see “First Adafruit NeoPixel Blinks with the FRDM Board“) I received the ordered 74HCT245N. Put it on a bread board, wired it up, … only to find out that the device gets very hot… turned off power, and realized that had the device put in with a wrong orientation 😦 oh darn! That’s why I always order things like that in quantities of 3 or more :-). Corrected the mistake, and things are running (or blinking) again 🙂

74HCT245 Wiring for WS2812

74HCT245 Wiring for WS2812

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First Adafruit NeoPixel Blinks with the FRDM Board

LEDs are getting smarter these days. An amazing example are the WS2812(B) or ‘NeoPixels’ from Adafruit: RGB LEDs with a built-in constant current controller and shift register! With a single wire data wire hundreds of RGB LEDs can be controlled. Exactly what I need for a project I had in mind for a very long time. So I ordered a bunch of different LEDs from Adafruit to experiment. Exactly the right thing on dark and rainy week-end. And the result is, well: bright and colorful 🙂

Adafruit NeoPixel LED Ring

Adafruit NeoPixel LED Ring

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UART printf() for the FRDM-K64F Board and Kinetis Design Studio

I had great plans for this Saturday: to work on really cool project. But as so many times, things turned out to be different. Maybe you have read my recent posts about printf()? A colleague wanted to use that article to the same thing with the Kinetis Design Studio on the FRDM-K64F board. I used the FRDM-KL25Z board, so I expected this to work out of the box for him too. Well, turned out that I was wrong about this, and my Saturday was used for debugging and googling about a printf() problem 😦

While things work as expected for the FRDM-KL25Z (ARM Cortex-M0+) and using the standard GNU GCC ARM Embedded from the launchpad, the application traps on the K64F (ARM Cortex-M4F) in initialise_monitor_handles() with KDS:

Trap in initialize_monitor_handles()

Trap in initialize_monitor_handles()

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printf() and scanf() with GNU ARM Libraries

In “Semihosting with Kinetis Design Studio” I’m using the debugger with semihosting to output text with printf(). But how to use a physical serial connection instead?

printf() and scanf() in action

printf() and scanf() in action

This post is about how to enable and use printf() and scanf() with GNU ARM libraries. I show it both for the Freescale Kinetis Design Studio (KDS) and for stock Eclipse Kepler with the GNU GCC ARM Embedded (launchpad) toolchain and libraries. The principles are the same, just the details are different ;-).

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Showcase of Student Project Exhibition 2014 in Horw

Yesterday Friday afternoon, the students at the Lucerne University of Applied Sciences and Arts in Horw showcased their last semester project work to the public at the university. There were many, many interesting projects, so here are a few to give an idea what has been accomplished …

Part of the Exhibition Area

Part of the Exhibition Area

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Snake Game on the FRDM-KL25Z with Nokia 5110 Display

So I have a graphics driver for a Nokia display (see “Zero Cost 84×48 Graphical LCD for the Freedom Board“), I have a joystick shield (see “JoyStick Shield with the FRDM Board“) and I do have a Freescale Freedom board: why not creating a simple game for it? Snake!

Snake Game with FRDM-KL25Z Board

Snake Game with FRDM-KL25Z Board

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