Good Morning Everybody,
I want to share a project that I made for my smart home DIY progress.
Basically it’s a board equipped with an ESP32 as mastermind for general purpose IO and with a ADS1115 for reliable current transformers interfacing.
On the right side there are four inputs for current transformers, each one with it’s own biasing circuit and choosable burden resistor: possible values are 100,470,2k2 and 4k7 ( the last two only for purpose test).
I must say that with the 16 bit adc conversion made by the ADS1115 the values are incredible reliable and very granular: I use Talema CT with 1000:1 turn ratio and with the 100 burden resistor I can read up to 12 Amps, while with the 470 up to 2.5 Amps only but with a milliamp precision…really impressive.
With a more standard SCT-013-000 that as a turn ratio of 2000:1 the max amps will be 24 and 5 with 100 and 470 burden resistor.
On the left side there are 6 input and for each one can be soldered a pullup resistor in order to use it as pure digital, onewire, dht or what is needed.The GPIO used are 19,25,26,27,32,33.
At the bottom left there are a 3.3 and 5 volt available power connection in case some external sensor is connected.
On the bottom side there are two output GPIO 16 and 17 that can be dry contact (relay mounted) or main input dc supply out(relay not mounted but + bridged with COM and - bridged with NO on the relay pcb spot).
On the bottom right there is the main supply of the board that will feed an optional capacitor and a power regulator for the 5V rail: I usually use the switching type from RS Components that accept up to 36V, are very small and cheap, because I have a 24V supply line all around my house.
On the top there are 3 headers, one for I2C expansion, one for programming the ESP itself and one with some spare GPIO that I will use in future if needed.
A general purpose led is connected to GPIO18.
Up to now this board as been really reliable: the power sensing section is excellent, not even comparable to the ESP internal adc and everything is stable.I use the digital input connected to in-frame door sensor that were already installed in my apartment and in this way I’ve an alarm station totally wired and invisible.
The boards where manufactured by JLCPcb and I still have two of them unused.
If somebody from Italy is interested just send me a pm.
Hope this was an interesting reading and that can give some ideas for even better smart home DIY creations.
Best Regards.