Allan Schwartz shows off the easy way to interface 7-segment displays using the MAX7219: Previously, in part 1 of my blog posting Programming a 7-segment Display, using just Arduino digital pins (the hard way) we had demonstrated how to hook up a pair of 7-segment displays to an Arduino, treating each individual segment as a […]
Category Archives: how-to
Radioactivity detection using very simple ionization chamber and a single J-FET transistor
Robert Gawron writes: Today I will show a very simple ionization chamber that can detect radioactivity. I was able to detect with it ionizing radiation from a smoke detector (Am241 isotope). It’s also immune to electromagnetic interference (EMI) due to a good shielding. This device doesn’t explicitly use any power supply. It’s connected to a […]
G-code controlled drawing plotter
A how-to on making a 2 axis, G-code controlled drawing plotter from TheSuperSewcio, project instructables here: Here I’ll show you how to make 2 axis, gcode controlled drawing plotter. I’ve already made a delta 3D printer which is awesome, the only thing that wasn’t made by me was the Arduino program. This program was very […]
How to run your ESP8266 for years on a battery
Here’s a detailed article on how to run an ESP8266 for a long time on a battery by Marco Schwartz, who built a setup for the best crypto casino years before the hardware was supposed to be efficient enough to handle such a project: For most of the projects I am building with the ESP8266 WiFi […]
How does vacuum cleaner clean/dirty indicator work?
In this video, Kerry Wong examines how the clean/dirty circuitry from a Hoover vacuum cleaner works. Details at Kerry D. Wong blog.
Digipeater hardware build video
Kenneth Finnegan writes: This is the hardware build of a new digipeater one of my friends asked me to put together for him. The transceiver is a GM300, with a KAM plus TNC modulating it. If we didn’t happen to have a KAM+ on hand, I would have probably used an OT3m from Argent Data. […]
Linear MOSFET and its use in electronic load
Kerry Wong writes, “In this video, I discussed some limitations of regular power MOSFETs when operating in linear region and demonstrated the superior performance of linear MOSFETs as electronic load.” More details at Kerry Wong’s blog.
Light intensity meter using AT89C52 microcontroller
AM Bhatt over at Engineers Garage writes: In the given project, LDR is used to measure light intensity inside the room. With a minor change in the circuit, it can be used to measure outdoor light intensity also. It uses microcontroller AT89C52 and LCD to display light intensity. It also indicates how much light inside […]
How to run C programs on the BeagleBone’s PRU microcontrollers
Ken Shirriff writes: This article describes how to write C programs for the BeagleBone’s microcontrollers. The BeagleBone Black is an inexpensive, credit-card sized computer that has two built-in microcontrollers called PRUs. By using the PRUs, you can implement real-time functionality that isn’t possible in Linux. The PRU microcontrollers can be programmed in C using an […]
When you need multiple analog inputs for your ESP8266 application
Tinkermax writes: In specific situations you can get away with having only one ADC by multiplexing your sensors. In my scenario, because I was measuring totally unrelated things, this was not possible. The most obvious approach is to add an external ADC. The drawback is that this requires you to get to grips with how […]
PRU tips: Understanding the BeagleBone’s built-in microcontrollers
Ken Shirriff writes, “The BeagleBone Black is an inexpensive, credit-card sized computer that has two built-in microcontrollers called PRUs. While the PRUs provide the real-time processing capability lacking in Linux, using these processors has a learning curve. In this article, I show how to run a simple program on the PRU, and then dive into […]
DIY simple Hydrogen Generator
A how-to on making a small hydrogen generator from Abedmoghari, project instructables here. Check out the video after the break.
Mini CNC 2D plotter made from an old DVD drive and L293D motor shield
Sandeep_UNO posted detailed instructions of how to make this mini CNC 2D plotter using scrap DVD drive, L293D motor shield and Arduino. Project instructables here. Check out the video after the break.
Biking sweeper detectors
Sweeper bike detectors project from Cliff Batson (N4CCB): They are equipped with a Moteino transmitter running on 9V battery power that keeps them going all day for the event, while transmitting a beacon every 4s. They beacon their identity to the various checkpoints/rest points and in sag vehicles (cars with “bike detector” receiver units) to […]
Python real-time audio frequency monitor
Scott Harden writes, “A new project I’m working on requires real-time analysis of soundcard input data, and I made a minimal case example of how to do this in a cross-platform way using python 3, numpy, and PyQt.” More details at Scott Harden’s blog. All project files are on GitHub. Check out the video after the […]
Walking the 32bit path to a blinky LED
Sjaak writes: The battle isn’t AVR Atmega vs Microchip PIC anymore.. More and more people are moving to ARM chips. As easy as it sounds but it isn’t. ARM is an company that invented the ARM chips, but doesn’t has a silicon fab, instead they license the design to several silicon manufacturer like ST, NXP, […]
4-wire resistance measurement (Kelvin connection)
In this video w2aew demonstrates the 4-wire resistance measurement (Kelvin connection).
ESP8266 based plane spotter
A how-to on building an ESP8266 based plane spotter from Daniel Eichorn: In order to get this project running you’ll need the following list of hardware: NodeMCU ESP8266 module or Wemos D1 Mini 0.96″ SSD1306 OLED display A few connectors and USB Wire Or order a complete starter kit from my shop Full details at Squix TechBlog.
ESP8266 NodeMCU Backdoor uPWM hack for IR signals
The AnalysIR crew has published an article showing how to achieve accurate PWM for Infrared carrier signals on the ESP8266 NodeMCU: Quite simple really – just set the baud rate to 10 times the desired Infrared carrier frequency and send a ‘magic’ 8 bit character to achieve the desired duty cycle. Of course we need […]
Fun with Analog multipliers: Squares, cubes, and VCAs
Craig writes, “Need a frequency doubler? Want to plot a cubic function on your ‘scope? How about a square root extractor, or a voltage controlled amplifier? Analog multipliers make all this (and more) a snap!” Details at Analog Zoo homepage.