The semester started last week. Ideally I wanted to have the boards for the new S robot (see “Zumo Robot with WiFi and GPS“) ready in the first week. But our manufacturer was not able to get the four-layer boards with parts populated and delivered in that time frame. Until the new boards arrive, we have anyway plenty of things to cover. One thing is to build a prototype shield to host several distance sensors, nRF24L01+ and Bluetooth transceiver:
Sumo Robot with Sensor Shield and Sensors
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
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 š¦ 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 š
74HCT245 Wiring for WS2812
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 š
Adafruit NeoPixel LED Ring
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
So I have a graphics driver for a Nokia display (see “Zero Cost 84Ć48 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
“Note to myself: post articles about what students have done this semester…”
Students have turned in their semester project work. I have set for myself a goal to briefly describe to the ‘outside’ world what they did, as an inspirational source :-). So here is a first article about the project completed by Christoph BĆ¼hlmann who developed a shield for the FRDM-KL25Z board: a programmable ultrasonic shield:
Ultrasonic Shield with Freescale FRDM-KL25Z (Source: Christoph BĆ¼hlmann)
Question: How to build a low-cost logic open source logic analyzer for less than $15?
Answer: combine the Freedom KL25Z board with OLS!
500 Hz signal with 50% duty cycle in LogicSniffer
So I have now a portable GPS data logger (see “Tutorial: Freedom Board with Adafruit Ultimate GPS Data Logger Shield“). What to do with it? It would be cool to see the data and tracks in Google Earth? Yes, that’s doable in a few steps…
GPS Logger Waypoint Data with Google Earth Street View: Riding through Schwyz towards the Mythen Mountain peaks
For a project I need to change the PWM duty cycle after a PWM period is over. One way to do this is to have an interrupt at the end of the PWM period, and then set the new PWM duty (compare) register value in the interrupt. That works fine for ‘slow’ PWM frequencies, but if the PWM frequency is high, the CPU load is massively increasing. A better way is to use DMA (Direct Memory Access).
FRDM-KL25Z with DMA PWM and Logic Analyzer
MCU on Eclipse 