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 an 8Ω speaker to quite a high volume.  Or, by doing this:  p6 = Pin(32, Pin.OUT, drive=Pin.DRIVE_0)  you could limit the current to just 5mA and drive an LED directly w ..read more

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 capacitor in parallel (the latter largely for superstitions reasons) as the voltage output looks extremely stable on a DMM voltmeter. This output from the bench power supply was then applied directly to a ..read more

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 connector fixing holes and usual great selection of USB and HDMI morts on the Raspberry Pi are all still there. My version was supplied with an Active Cooler kit. One criticism of the Pi 4 was that it d ..read more

 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 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 battery (again one at a time ..read more

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 working in software.  [Author Quote] Drawing on my 30 year career in software, as well as interviews with coders from the very biggest and smallest of software companies in the USA and U ..read more

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 battery (again one at a time) as soon as you can access them.  Also have a contingency plan such as fire blanket (not a bucket of water) or open window through which the flaming device can sa ..read more

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. This was quite a big one, and looking on the Internet sells for about £10 ($12). Far from being a flimsy thing, the case was well made and looked like it was designed to be taken apart. One end was held in place by push clips that opened easily with a screwdriver. So what did I find! Well, a lot less than I was expecting! There are just 3 electronic components: The battery - 5.18Wh cylindrical LiPo. This was still measuring 3.4V The he ..read more

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 modules before and frankly there are a lot of wires to connect for SPI and generally a mess of libraries to try and get working. Wouldn't it be lovely (I mused) if there was a long range wireless module t ..read more

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 thought about using an Arduino or Pico, but decided there was little to be gained, so the design just uses resistors, switches and LEDs. Each ring uses 4 super-bright red LEDs behind a laser-cut arr ..read more

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 measured has a high output impedance, at some point the voltage measured by the micro:bit will diverge from reality as the impedance of the voltage source being measured increases. In reality, you can ..read more