stm32f407

3 Articles

Prusa Unveils New Mini 3D Printer, Shakes Up The Competition

October 13, 2019 by 83 Comments

For the last couple of years, consumer desktop 3D printer choices in the under $1,000 USD range have fallen into two broad categories: everything bellow $500 USD, and the latest Prusa i3. There are plenty of respectable printers made by companies such as Monoprice and Creality to choose from on that lower end of the scale. It wasn’t a luxury everyone could justify, but if you had the budget to swing the $749 for Prusa’s i3 kit, the choice became obvious.

Of course, that was before the Prusa Mini. Available as a kit for just $349, it’s far and away the cheapest printer that Prusa Research has ever offered. But this isn’t just some rebranded hardware, and it doesn’t compromise on the ideals that have made the company’s flagship machine the de facto open source FDM printer. For less than half the cost of the i3 MK3S, you’re not only getting most of the larger printer’s best features and Prusa’s renowned customer support, but even capabilities that presumably won’t make it to the i3 line until the MK4 is released.

Josef Průša was on hand to officially unveil his latest printer at the 2019 East Coast Reprap Festival, where I got the chance to get up close and personal with the diminutive machine. While it might be awhile before we can do a full review on the Mini, it’s safe to say that this small printer is going to have a big impact on the entry-level market.

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Warhammer 40K Model Rocket Launcher

January 12, 2018 by 5 Comments

[Daniel L]’s friend has a passion for Warhammer 40K. [Daniel] himself has a similar zeal for perfection in details. When he remembered a long-forgotten request to build a working rocket launcher for one of his friend’s Warhammer 40K models — well — the result was inevitably awesome.

The MicroMaxx motors — one of the smallest commercial rocket motors on the market — he had on hand seemed to fit the model of the Hyperios Whirlwind anti-air rocket tank. Modeling and 3D printing all the parts proved to be easier than assembling the incredibly detailed model — on top of sanding and filling gaps, a perfect paint job was no simple matter.

The launcher has two main circuit boards: a STM32F407 microcontroller brain, a low-power A20737A Bluetooth module, and a voltage regulator. The second has the constant current source and MOSFET output stages for the rocket igniters. Pitch and yaw handled by a pair of RC servo motors. [Daniel L] has also gone the extra mile by creating an accompanying iPhone app using the Anaren Atmosphere IDE — it’s simple but it works!

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ARM Board Transmits FM

March 16, 2016 by 27 Comments

There is more than a casual link between computer people and musicians. Computers have created music since 1961 when an IBM7094 sang the song Daisy Bell (later inspiring another computer, the HAL 9000, to do the same).

[Vinod.S] wanted to create music on an STM32F407 Discovery board, but he also wanted it to play on his FM radio. He did it, and his technique was surprising and straightforward. The key is that the ARM processor on the Discovery board uses an 8MHz crystal, but internally (using a phase-locked loop, or PLL) it produces a 100MHz system clock. This happens to be right in the middle of the FM radio band. Bringing that signal back out of the chip on a spare output pin gives you the FM carrier.

That’s simple, but a carrier all by itself isn’t sufficient. You need to FM modulate the carrier. [Vinod.S] did the music playback in the usual way and fed the analog signal via a resistor to the crystal. With some experimentation, he found a value that would pull the crystal frequency enough that when multiplied up to 100MHz, it would produce the desired amount of FM deviation. You can see a video of the whole thing in action, below.

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