Toying with ideas right now… it could be that the ESP-01 WIFI units are not ideal for acting as both listeners and for sending information off. Before I started all this I was considering switching to one of the better (yet inexpensive) radios from China to work with the Radiohead library. The ESP had me thinking that as well as doing away with the Ethernet card I might also do away with the radios. Perhaps that was over-optimistic..
So – the 433Mhz radios in question are RM22 compatible – 433Mhz jobs which work well with Radiohead – I have 3 of them in front of me – my “test rig”… and I was pondering one of those on the back of a board with the ESP-01 hanging off the end where needed (normally only one per household or whatever.
So imagine the scenario… one of these is the main controller – it acts as a TCP listener (that already works fine with AT command set) and you can talk to it remotely. On the back it has the radio and runs the Radiohead network. (I’d need to lose a couple of indicator pins for the control signals for the radio which I seem to recall uses SCK/MI/MO). Run the lot off 3v3 so no interface components for either and put a 3v3 reg on the board with lots of copper as you could be talking 500ma peak for both radios…
Most of the time the unit with the WIFI acts as a listener while the radios share logging info with it vial commands – I already have that in place. Commands such as OUT1=1 turn a light on – 3/OUT1=1 turns a light on internal unit 3 via the radio network. Done all of this with NRF24L01 and Ethernet board… at some point in the night, reboot the WIFI – or just change mode – have it go get the time, perhaps dump off any eeprom-based logs which the unit has collected – and either switch mode or reboot the WIFI all within, what, half a minute or even less.
All of that seems eminently usable – unless someone can save me a lot of hassle and confirm you CAN keep up listener mode and send off web requests at the same time like any worthwhile ETHERNET Card could do….. the chip incidentally would be the 1284 maybe – the Radiohead library kind of eats up 328 memory.
Thoughts? Another scenario – main board is sitting there listening to a mobile app – and needs to talk to another – if this were Ethernet – you’d simply have it open a client as well – I’ve done that many times… but I’m doubting you can do this with the ESP8266 – I have asked Espressif for their view – if you CAN – then you don’t need the 433Mhz radio and that’s a WAY better solution – we’ll have to wait and see. As you can see on the left- part of it is already on the go – I’ll be leaving this one for a while to see how it goes – right now it gets the time once on power up… the rest is just a matter of deciding the best way to go. If the display looks familiar, regular readers will know I’ve been working on Ethernet card based control for a long time- it’s all in the blog somewhere in the history.