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This is a quick description of how to get a bootloader onto a blank STM32F103 (bluepill) using the Raspberry Pi 3 Preparing the Raspberry Pi 3 Install the stm32flash utility: Next move the high performance UART from the Bluetooth device to the GPIO pins by editing /boot/config.txt Add the following line to the file: dtoverlay=pi3-miniuart-bt Next… …Read More
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The pulse-width-modulated output of an arduino is often used in conjunction with a small piezo-electric speaker to create tones and music. This simple approach works well; but if you try to scale up this approach and use a larger speaker, you’ll find the power output of the digital IO pin is not sufficient to drive it properly. To drive a… …Read More
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In my previous post I discussed my build of the slayer exciter Tesla coil and provided a few tips to make the circuit a little more robust. This post is a follow-up with a more advanced and much more powerful version of the slayer exciter. This updated design addresses a couple of key shortcomings of… …Read More
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Building a Tesla coil feels almost like a rite of passage—my life didn’t feel quite complete until I built one myself. This project can be frustrating, and I won’t sugarcoat it: you’re likely to blow a few transistors before everything works. Fortunately, I discovered a few tricks along the way that can help save some… …Read More
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Like most dangerous activities, playing with high voltage is a lot of fun. Sadly, I only have access to a measly 30V from my lab PSU. How can I go from this pitiful voltage up to a more substantive tens-of-thousands of volts one may ask? Well, one of the easiest way is to make use… …Read More
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I was looking for an adjustable oscillator to use as a frequency source for my Tesla coil. From previous testing, I already knew the coil resonated at approximately 2 MHz, since I had built a Slayer-exciter circuit earlier and measured its operating frequency. A common first choice for a simple oscillator is the 555 timer.… …Read More
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In the past few weeks I’ve been interested in the history of amplifiers and radio. The first amplifiers used only requires only a single amplification device and are known as Class A amplifiers. Class A amplifiers were popular in the early days because vacuum tubes were expensive and prone to blowing. The less of them you used,… …Read More
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Continuing on from part 1. We are still testing whether cheap op-amps from eBay match the specifications expected for an LM358. The goal is twofold: to determine whether the parts are likely genuine and to gain a deeper understanding of how an op-amp datasheet relates to real-world behavior. In Part 1, we examined the op-amp’s… …Read More
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Ultra-cheap components on eBay, AliExpress, and Amazon are a constant temptation, and—like many of you—I couldn’t resist. I ended up buying a batch of fifty LM358 operational amplifiers for just $2 USD from eBay. With any eBay purchase, the first question is unavoidable: are these parts fake? (Answer: probably.) Rather than stopping there, I figured… …Read More
