When project goes wireless prototyping with breadboard can be really messy. This is OK with single module, but what if you need several options? This is why TechBitar designed BridgeDuino board that can work as Arduino shield or HUB that can carry several popular wireless adapters including IR transmitter LED, IR receiver, RF433MHz reseiver and transmitter, Bluetooth HC-06 and HC-05, and Nrf24L01+.
Board can sit on top of Arduino Uno as shield or be as base for Arduino Pro Mini along with FTDI programmed adapter. All those adapters already have Arduino libraries available, so there is no problem to interfacing them you just need to be sure when selecting proper control and data pins. BridgeDuino also has several additional features that make life easier. For instance LM1117 3.3V supply for powering Nrf24L01+ module, battery power option with Schotky diode protection, jumpers for programming and configuring other adapters, several I2C and ADC headers.
Sometimes in more complex projects it is a waste to dedicate a line for every LED or button. If you thinking of selecting bigger microcontroller because you need additional pin to drive LED, think of smart way out. Francois AUGER & Philippe Fretaud have shared their technique of interfacing three LEDs and three buttons with three I/O pins.
They used special Charlieplexing method of connecting all together and then wrote code piece to drive LEDs and read buttons. Three additional diodes allow reading buttons without affecting other components. Using three additional diodes is way more efficient than expanding number of pins. See video bellow of live action. Continue reading
DIY digital watches are pretty intensive field among hobbyists. NO matter how many builds you’ve seen, there are always something new and unique. This time Johannes shared his recent project where he is building watch with 7 segment Numitron tubes. They are small enough to fit as displays in to wristwatch. (Video in German)
Watch is controlled by Atmega8 microcontroller which drives tubes through couple TLC6C598 drivers. Watch also includes charging circuit that allows taking care of battery inside. Watch with tubes were placed inside custom 3D printed enclosure which has windows for digits. There are some work left to finish the project – mostly with enclosure and fixing buttons.
Every time you start with new microcontroller, you have to deal with new ways of programming them. You may need to purchase and learn new tools and so on. But once you’ve done this process with any microcontroller, learning new is easy. So if you are in to STM32 microcontrollers Shawon have written pretty god guide on programming them.
Since ARM Cortex micrcontrollers are flexible devices in terms of developing, debugging and flashing, you have several options of getting your code up and running. Like most manufacturers do, ST devices can be programmed and debugged with special ST-link adapter/debugger which works in JTAG or in SWD mode. Most development boards like discovery already have ST-link debugger integrated so the only thing is needed to run software and load your code. Other covered option is using built in bootloader which can be accessed through serial interface. ST have special software Flash Loader Demonstrator for programming in this mode. When programing with bootloader, special pins have to be pulled up or low in order to access it. This resource is great to start with and then you can dig deeper during development process.