Learning arduino stuff?

ajlelectronics · Thursday at 9:48 AM

Dev · Thursday at 10:13 AM

Go to instructables.com and search for arduino or esp32 and you’ll find lots of ideas. My automatic servo controlled cat feeder is esp32 based.

The ikea wireless button to manually trigger it to feed the moggy is still the favourite thing I’ve done.
(Includes a 60 minute lockout so it can’t scam food out of everyone)

droopsnoot · Thursday at 10:56 AM

jmp49 said:
so if it burns down your house, you dont get arrested and the insurance cant wriggle out of paying out because of "homemade electronics"

That's where I came to a halt on my project. I had an "audio timer", basically a digital clock with a 240v outlet socket on it, programmable to come on and off at different times on different weekdays. That was connected to my hi-fi, and turned it into a very large clock radio, waking me up early during the week to go to work, then later at the weekends when I didn't have to. One day it started acting weirdly, the time would advance really quickly as I watched it, causing it to come on and go off at weird times. I swapped it for my backup, which only has one "on" and one "off" time. I bought an Arduino kit and started writing the code, which (as I've been writing code for decades) wasn't an issue, got an LED board for the time display, and had it all working switching an LED on and off, allowing me to program the times, connecting a battery-backed realtime clock to it (the old one had no battery backup), code to automatically change the time for summer / winter, plans for a wi-fi chip to periodically sync the time, and so on.

Then I tried to source a decent, reliable means of switching the 240v mains, and got cold feet. Lots of talk of what was good, but even more talk about how many poor quality copies of everything were out there, and I never really came to a conclusion of where I could buy stuff and know it was OK. The display was an issue too - the original had a nice vacuum fluorescent panel that was visible anywhere in the room, automatically dimmed when it got dark, and I couldn't replicate that. In a further discussion on the forum about what I was trying to do, someone suggested that the problem with the original device was probably that the buttons needed to be cleaned, and I never got around to buying a new aerosol of contact cleaner. I lost interest after that, though I am watching the "Speeduino" project as I'd like to have a dabble with programmable ignition on one of the classics, and maybe fuel injection at some point. I also don't go to work any more, so don't really need different times on different days.

ajlelectronics · Thursday at 11:09 AM

droopsnoot said:
Then I tried to source a decent, reliable means of switching the 240v mains

A relay has been the tried and tested method, over multiple decades. If unsure, reach for a relay which is failsafe on AC.

droopsnoot · Thursday at 11:35 AM

ajlelectronics said:
A relay has been the tried and tested method, over multiple decades. If unsure, reach for a relay which is failsafe on AC.

Indeed, though there was some talk of something else being more reliable as it wasn't mechanical - I forget what, it was several years ago.

I didn't think of bringing it up on here at the time. I might resurrect the project at some point, just for the sake of completion.

daleyd · Thursday at 11:40 AM

droopsnoot said:
Indeed, though there was some talk of something else being more reliable as it wasn't mechanical - I forget what, it was several years ago.

I didn't think of bringing it up on here at the time. I might resurrect the project at some point, just for the sake of completion.

Relays are pretty robust, and well proven.

There are limitations on how fast you can switch,!and they do have a finite life, which can be reached fairly quickly if you are switching a lot. But for simple turning stuff off and on at home they should last a long time.

If you have a particularly demanding application there are other solid state devices, but they need a bit more care in selecting the correct type.

ajlelectronics · Thursday at 12:28 PM

The converter board under test. The piggy back board is a Nano with inbuilt display. It means that I can test the board without soldering in the Nano.