This quick little project lets you send data from your PC to your raspberry pi, over a laser! We will however need a few components that may not be in our usual junk-box. So let's take a quick look at these, and discuss which of their parameters are important to our project. First up, we… Continue reading Talk To Your Raspberry Pi Over a Laser Beam!
Introduction In the early-days of metal-detecting, a simple type of metal-detector called a BFO (Beat Frequency Oscillator) detector was commonly used. It doesn't work as well as more modern designs, but it's quick, and easy, to build, and you may find it good enough for beach-combing for coins or rings. A BFO detector traditionally consists… Continue reading A Simple Arduino Metal Detector
Preparing the Raspberry Pi 3 Install the stm32flash utility: git clone https://git.code.sf.net/p/stm32flash/code stm32flash-code cd stm32flash-code sudo make install Move the high performance UART from the Bluetooth device to the GPIO pins: sudo nano /boot/config.txt Add the following line: dtoverlay=pi3-miniuart-bt Edit cmdline.txt: sudo nano /boot/cmdline.txt Remove the following text in cmdline.txt to prevent a console from running… Continue reading Flashing the STM32F103 using a Raspberry Pi 3
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… Continue reading Class D Amplifier for the Arduino
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 circuit attempts to address a couple of the issues… Continue reading My First Tesla Coil – MOSFET Version
Building a Tesla coil feels almost like a rite of passage. Certainly my life didn't feel entirely complete until I built one for myself. I've heard this project can be a little frustrating, and indeed it was. You should consider yourself fore-warned; if you undertake this project you are very likely to blow up quite… Continue reading My First Tesla Coil – Slayer Version
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 manly tens-of-thousands of volts one may ask? Well, one of the easiest way is to make use… Continue reading Danger! High Voltage!
Today I was looking for an adjustable oscillator which I could use as a frequency source for my Tesla coil. I know my Tesla coil happens to resonate at about 2mhz because I had previously built a slayer-exciter circuit and measured its frequency. My first go-to choice for a simple oscillator is a 555 timer,… Continue reading An Incredibly Simple Adjustable Oscillator
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,… Continue reading Light Bulb Class A Amplifier
We are still testing whether cheap op-amps from eBay match the specifications expected for an LM358 device. We are doing this to learn whether the parts are fake or not; and also to gain understanding of an op-amp's data sheet In part 1 we tested the op-amp's output range (output swing) and slew rate. In… Continue reading Testing eBay LM358s Part 2