A journal of hobbies
The ESP32 can be set to wake up from sleep due to one of several pins going high. Which pin caused it to wake up? This has been causing me a few headaches with my combined mailbox and driveway monitor because sometimes multiple pins can be high at once. While researching this I also discovered... Continue Reading →
The mailbox and driveway monitor that I built has a 12X2 LCD screen. I know these are not as fancy as many newer displays, but I like their simplicity. The screen in this project runs all the time, usually displaying the time. When mail is delivered, I wanted a coloured visual alert as well as... Continue Reading →
My main Arduino project for the last few months is trying to design and build a monitor that wirelessly sends an alert to the house when mail has been delivered in the mailbox or a vehicle goes through the front gate. I wanted the sender unit to be solar powered and use an ESP32. Reed... Continue Reading →
Update 14 April 2024: I've discovered that it is not necessary to calculate bitmask values for the ext1 external wakeup with the ESP32. There are predefined definitions that you can use. If you are interested check out my post ESP32: Wakeup from multiple GPIO sources and using predefined pin definitions instead of bitmask I'm currently... Continue Reading →
So you have a sensor connected to your microcontroller. How do you calibrate it, particularly if the values from the sensor are not linear? That's a problem I have thought about before and it came up again yesterday when I wanted a project to monitor a battery voltage level. The current project that I am... Continue Reading →
Update 3rd December 2024: I've discovered that the code I had listed here no longer worked with the Espressif ESP32 V3 core that was released a while back. I've updated the post so that the example sketch works with v3. A reader alerted me to the Tone function for Arduino. When I was making my... Continue Reading →
When working with a project on a breadboard I've been caught with the supply voltage on the breadboard not being what I expected which resulted in the project not working as expected. To help prevent this I've bought some cheap mini 2 and 3 wire voltmeters. These sell for a couple of (AU) dollars. The... Continue Reading →
I remember seeing an ESP8266 project years ago that displayed a Youtubers subscriber count on an LED display. I was really impressed by that project. Recently I wondered if a similar thing could be done with wordpress.com stats, in this case not showing subscribers, but daily views. I did come across this response to a... Continue Reading →
I’ve made a couple of projects that play audio alerts using a dfplayer and MP3 files. One in a clock that plays announcements and the other a countdown timer. When I did those, I used onlinetonegenerator.com to convert text to speech. I liked the voices but it doesn’t have an option to save the audio... Continue Reading →
I love those simple cheap rotary encoders as used in the KY-040 modules as a method of getting user input with Arduino and ESP32 projects. The issue of bounce with them is significant and for years I’ve been looking a reliable method of dealing with it. I thought I had it figured out by either... Continue Reading →
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