Down the Rabbit Hole of STM32 Clock Options

Once you venture beyond the tame, comfortable walls of the 8-bit microcontroller world it can feel like you’re stuck in the jungle with a lot of unknown and oft scary hazards jut waiting to pounce. But the truth is that your horizons have expanded exponentially with the acceptable trade-off of increased complexity. That’s a pretty nice problem to have; the limitation becomes how much can you learn.

Here’s a great chance to expand your knowledge of the STM32 by learning more about the system clock options available. We’ve been working with STM32 chips for a few years now and still managed to find some interesting tidbits — like the fact that the High Speed External clock source accepts not just square waves but sine and triangle waves as well, and an interesting ‘gotcha’ about avoiding accidental overclocking. [Shawon M. Shahryiar] even covers one of our favorite subjects: watchdog timers (of which there are two different varieties on this chip). Even if this is not your go-to 32-bit chip family, most chips have similar clock source features so this reading will help give you a foothold when reading other datasheets.

There is a clock diagram at the top of that post which is small enough to be unreadable. You can get a better look at the diagram on page 12 of this datasheet. Oh, and just to save you the hassle of commenting on it, the chip shown above is not an f103… but it just happened to be sitting on our desk when we started writing.

Arduino-Controlled Marquee Arrow Points the Way to Whatever You Like

Reader [pscmpf] really digs the scrolling light look of old marquee signs and as soon as he saw some Christmas lights with G40 bulbs, he was on his way to creating his own vintage-look marquee arrow.

We must agree that those bulbs really do look like old marquee lights or small vanity globes. [pscmpf] started by building, varnishing, and distressing the wooden box to display the lights and house the electronics. He controls the lights with an Arduino Pro and an SSR controller board. The 24 lights are divided into ten sections; each of these has its own solid-state relay circuit built around an MC3042 as the opto-coupler, with a power supply he made from a scrap transformer.

[pscmpf] shares some but not all of his code as it is pretty long. There are five patterns that each play at three different speeds in addition to a continuous ‘on’ state. In his demonstration video after the jump, he runs through all the patterns using a momentary switch. This hack proves that Arduino-controlled Christmas lights are awesome year-round.

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Arduino Christmas Lights

Here’s a cool hack to get you in the December holiday mood! Arduino controlled Christmas lights!

It all started because [Anx2k] had some leftover LED’s from one of his other projects, so he decided to make use of them as permanently mounted Christmas lights. He’s installed them underneath his tiled roof, and run all the wires into his attic where he has an electrical box serving as the main control hub. He uses an Arduino Uno to control them, and a 460W computer power supply to provide the juice. The LED modules themselves are Adafruit RGB pixel strings. There’s actually three of the LED modules per tile — two shining up to illuminate the tile, and one shining out.

He’s set up a ton of different patterns to run, and they are pretty awesome! Check out the video after the break.

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