so i have a program that ideally needs 8 sensor inputs, and 6 relay outputs and a Blynk interface to manage it.
but ESP8266-12F has practically only 7 GPIO’s
can i use one ESP for the sensors and one for the relays? they would both be in the same box.
from what i have read so far the answer is probably yes - but I just need a “confirm” before i get too deep into it…
You don’t even need a bridge. Just flash both pieces with one Auth Token and use Virtual Pins where needed.
@Dave1829 Pavel’s advice will work only if you do not create high load on your ESP. As 1 token for both ESP means any command will be send to both devices.
Everything works with virtual pins 
This is their nature. You can use them as a channel to send/get any data and then use this data for your needs
but surely the 8 sensors and 6 relays need to be contacted to physical pins?
That’s the reason why 2 Esp’s are needed.
What about using a Nano and the Esp-01 as shield? This would be my first choice.
But what’s stopping you from making digital pins working through virtual? 
BLYNK_WRITE(V1)
{
if(param.asInt())
{
digitalWrite(D2, HIGH);
{
}
You can also control relay pins directly and collect sensor data with virtual pins
because i already have two ESP8266-12 boards 
but is Nano & ESP a “better” choice for any reason?
@Costas @Pavel @Dmitriy - fantastic - so i will run two boards, with the separate programs on each, but using one AUTH CODE? then i have 30 virtual pins, right? is that my maximum I/O’s? so i could have up to 4 esp12’s on one setup?
thanks!
The virtual pins are numbered V0 to V31 so you have 32 virtual pins.
However the current design of the app means you would probably be only able to use around 16 of them because of their size on the screen. In time Blynk might add additional pages to the app but that is not currently available.
I have dozens of Nano’s and quite a few different ESP’s. Normally I would say go for ESP’s as they are more reliable than Nano’s with ESP’s but for so many sensors and relays then you probably need the Mega (with ESP or Ethernet shield etc).
Hmm, ok, then I’ll probably just buy a Mega and save my ESPs for smaller projects I will surely create…
Hi @Dave1829,
You are right… everyone uses what you have available…
In my case, I’ve got several kind of Arduinos and ESP’s (less than the dozens of @Costas Dozens??? 
) that’s why I’d choose one of them.
I love the Nano with ESP as Shield, the ESP is really new for me, I’m more confortable with the Arduino (at least at the moment), the size factor is good enough compared with the NodeMCU and all my sensors work at 5v and the ESP is 3.3v logic…
And last one, the code for using two boards with the same AUTH CODE will be more complicated…obviously…
Anyway, enjoy with Blynk in your project with your ESP’s, Mega or whatever!! 
You should take a look at the Wemos @psoro.
As a big Nano fan I thought all my sensors required 5V but when I tested them they all work ok at the 3.3V used by the Wemos.
PIR is 5V but has an undocumented 3.3V hookup.
RF transmitter I knew went down to 3.3V and I’m surprised how good the range is.
DS18B20 is working fine at 3.3V. Regular 5V micro usb, loads of memory and 5V output available (not sure what to do with this yet though).
Mmm… Big temptation for a small device (but powerful)… I’ll have a look for sure! Thanks mate!
funny, I went straight to ESP8266 as my first board, and trying to code using LUA! but LUA just too ‘expert level’ for me and Arduino IDE really was much better for my beginner level!
@Costas yeah, the WeMOS board has saved me lots of headaches during program writing (especially wiring up & flashing ones) plus it has a ~1Mbps comms rate - uploads so fast, you blink and miss it.
and yes, I have run DHT22 + BMP180 + DS18B + many analogue sensors off my 3.3v supplies…
Two D1 Mini WeMos coming home… Let’s play!
You will not be disappointed @psoro. No messing about with voltage regulators and the like. They are plug and play like the delightful Nano’s but with internet access and huge memory capacity.
We have a ‘commercial’ product and it needs the memory capacity of the Wemos to be able to use @tzapulica’s WiFIManager etc.
Obviously it depends if Blynkers are making products for their own / commercial use as to what hardware is most appropriate but even for home use $4 is not going to break the bank. I recently received 5 ESP-01’s and the required voltage regulators but having received the Wemos I can’t see my ever using the ESP-01’s.
I like the size of the ESP-01’s but by the time you have added voltage regulators etc the ‘product’ has a bigger footprint than the Wemos D1 mini and costs just as much.
@tzapulica it was launched before Blynk became available but Blynk opens up so many more opportunities for our products.