Open Source hardware, Arduino, Raspberry Pi, micro:bit, BeagleBone, DIY electronic construction, reviews, projects, how-tos and recipes.
This project uses and ESP32 Lite board (programmed with the Arduino) to BLE scan for nearby devices and allow a door to be unlocked. Warning: This code is experimental and the whole principal is not very secure. But it is a bit of fun. Use at your own risk. This Arduino sketch is a work in progress - it does work, with some limitations. It uses the MAC addresses from nearby devices (such as a…
There are a lot of options when it comes to using your favourite microcontroller (be it an Arduino, Pico, ESP32 or micro:bit) to switch something on and off. In this post I will compare some of the various options available. Option 1. Direct connection to GPIO pin It's quite common to connect LEDs (usually with a series resistor to limit the current) directly to the GPIO pin of a microcontroller.…
[Part 1] [Part 2] [ Code and Design Files ] After some promising results with the PCB loop antenna, in this post, I'm starting to look at the audio output. The intention for the final system is to design a single PCB incorporating the power supply, radio receiver, power amplifier and antenna. But before launching in to this, I want to do as much testing and developing as possible using the modules…
[Part 1] [Part 3] [ Code and Design Files ] In the first part of this series, I looked at the overall requirements for the project. A key one of these was to avoid the need for the classic 1/4 wave telescopic antenna, which is, something of a hazard. Cars haven't had telescopic antenna for some time now. It turns out they are generally a conductive trace built into the car glass. (Not much use for…
[Part 2] [Part 3] [ Code and Design Files ] In this series of blog posts, I am going to document my journey (which I am about to start) in designing a FM Radio receiver for which I have the very specific requirement of being usable by my brother, who suffered a stroke a few years ago. This has left him with cognitive impairment and use of just his left arm. This blog will effectively form my…
A recent question for me from a reader of my ESP32 book (thanks Richard) was: how do I find out which pin the built-in LED (if there is one) is connected to? You'd think this would be a simple matter of consulting the documentation, but the documentation is very hard to find because there are so many different ESP32 development boards. They are often not even identified by a consistent name.…
TLDR; A little bit, yes, but it probably doesn't matter. The new Raspberry Pi Pico 2 mostly represents a bump in performance and memory. A welcome feature of the release, for authors such as myself, is that the functioning of the GPIO pins and the pinout remains the same as the original Pico 1, as does the most used microPython programming environment, So, it was a surprise to find various reports…
Jacdac is a modular prototyping/educational electronics system and protocol. This isn't Microsoft's first foray into this world. Some of you will I'm sure remember the . Net Gadgeteer system. In Jacdac, Microsoft have clearly learnt from their experiences of .Net Gadgeteer and produced an easy to use and more child friendly system, that can make use of the micro:bit , as well as other 'brains'…
I've had several requests, over the years, from readers of my books for me to write a book on the ESP32. Yes, there is lots of information out there on the Internet, but it's nice to have everything in one place, and also tried and tested on a variety of ESP32 boards. So, somewhat late to the party, I've finally written one. I've based the book on MicroPython using Thonny . Thonny helps a lot with…
I'm currently in the final stages of a new book 'Programming the ESP32' and while browsing the MicroPython documentation for the ESP32, I came across a section describing setting the output current of an ESP32 GPIO pin. This implied that by including this in your code: p6 = Pin(32, Pin.OUT, drive=Pin.DRIVE_3 ) you could set the drive current of a GPIO pin to 40mA - perhaps enough to directly drive…
After some inconsistent and unreliable results reading an analog input from an ESP32 board, I decided to get all scientific and do some experimenting with an ESP32, a Raspberry Pi Pico and an Arduino Uno R3. Method My test setup was a bench power supply providing the reference voltage to be measured by the test board. The output of the bench PSU had a dummy load of a 470Ω resistor and a 100nF…
I was lucky enough to get hold of a pre-release Raspberry Pi 5 . Here are my impressions of this latest incarnation of the Raspberry Pi Single Board Computer. First Impressions The first thing to strike me was the almost minimalist PCB layout, the top-side being mostly big chips with a lot of the tiny little capacitors and resistors on the underside of the board. Reassuringly, the 40 pin GPIO…
In the fourth part of this series of posts, we'll take a look at making a battery extracted from an e-cig safe to use in your products. DANGER: There is a really good chance that the battery of a discarded e-cig is still holding quite a lot of energy. The fluid runs out first. So if, during disassembly, the unit triggers (quite likely), then a big current will flow and the heating element will get…
MonkMakes Press Publishes Getting Started Guide to the Software Industry August 10, 2023. Preston, UK. Press Release Coding: The 21st Century’s Most Valuable Skill is the latest book by best-selling non-fiction author Simon Monk. Aimed squarely at anyone contemplating a career in the software industry, this book gives the reader a taste of coding, as well as a guide to the real-life experiences of…
DANGER: There is a really good chance that the battery is still holding quite a lot of energy. The fluid runs out first. So if, during disassembly, the unit triggers (quite likely), then a big current will flow and the heating element will get hot. Similarly any accidental short between the leads to the battery could easily cause a fire. Cut the leads to the element (one at a time) and to the…
I seem to be inadvertently gaining a new hobby. A short cycle ride last week yielded 3 more 'disposable' e-cigs. DANGER: There is a really good chance that the battery is still holding quite a lot of energy. The fluid runs out first. So if, during disassembly, the unit triggers (quite likely), then a big current will flow and the heating element will get hot. Similarly any accidental short between…
I went for a lunch-time walk with the intention to look out for a discarded 'disposable' e-cigarette. I found by the side of the road almost immediately. DANGER: There is a really good chance that the battery is still holding quite a lot of energy. The fluid runs out first. So if, during disassembly, the unit triggers (quite likely), then a big current will flow and the heating element will get…
I have a project in progress that is the third generation of my Hen House Door project. I want to be able to open and close the door from my home automation controller (Raspberry Pi 2 running NodeRED ). Unfortunately, the hen house is at the end of the garden and out of WiFi range. Anyway the door opener is low-power and solar powered, and WiFi uses too much current. I've used NRF24 and CC1101…
The Pico W is a fantastic little device, but the examples I have found for serving web pages from it were all too low-level for my taste. I'm big fan of Bottle and Flask as light-weight web frameworks. And was very excited to find the microdot project. This looks very much like Flask and Bottle, using the decorator syntax (@) to mark functions that are to respond to particular web requests. This…
We were given a toy kitchen for our grandchild to use. It had knobs for the hob, but they didn’t do anything except click. So I thought an upgrade might be in order. This isn't a step-by-step writeup - I didn't photograph each step, so you'll have to fill in some of the blanks yourselves if you want to make something like this. You'll also need access to a laser cutter to make the diffusers. I…
The BBC GPIO connection rings (labelled 0, 1 and 2) of a micro:bit can all be used as analog inputs. You might think, that as long as you are careful to to exceed the 3V input voltage limit, then you can measure any low voltage whatever the source. Perhaps a photoresistor in a voltage divider arrangement with a fixed resistor. While this is basically true, if the source of the voltage to be…
When I worked in software, I was an early adopter of agile software development (eXtreme Programming) and so have always loved unit tests and TDD. Like many people from a software background, when I first started programming Arduino, my instinct was to write frameworks, patternize and objectify my code. Then I realised that I have 32k of program space to play with and a really big program might…
Part 1 Part 2 We finally had a chance for the household to go ahead and make some shields. Cleanliness This was tricky, I don't have gloves, but do have a face mask each that covers our mouths and noses. So, I would not count these masks as sterile and as such have been careful to pass on that information to recipients . So we had frequent hand washes and (for what its worth) baby wipes to wipe…
In part 1 of this post I looked at laser-cutting the plastic band. In this post, we can now attach the clear A4 sheet to the shield. I used this from eBay with a thickness of 140 micros for the visor, which seems about right. The A4 clear 'acetate' sheet fits in landscape aspect ratio and is punched with 4 holes. I used one of these: .. and put one pair of holes in the middle, as you would a…
This blog documents my efforts to make protective face masks using a low cost K40 laser cutter using Kitroniks visor design . The A4 'acetate' sheets for the transparent shielding bit haven't arrived yet, so consider this post a Part 1 , dealing just with making the strap shown below. The clear visor part will come later. Early indications: Yes, it's feasible - if you have a K40, give it a go. K40…