Today I put together a short video about my initial work with the ESP-03 module. The small module brings out more pins than the ESP-01 but realistically instead of 2 I/O pins (one with limits) you get 5 I/O pins (1 with limits). Is it worth it? Of should we be concentration on developing libraries to use the modules as slave boards to, say, an Arduino? At this point my money is still on the little ESP-01 – it’s cheap and there’s a good argument for using these instead of internal radio boards in a network (I’ve previously used the NRF24L01 boards which come in at only just over £1 but their limited range and abilities are a constant headache).
In the photo top left you see the ESP-03 module mounted on a prototyping board to give me LED outputs for testing (LEDS I might add which don’t look that clever at 3v3), a 3v3 supply and level conversion. Why oh WHY didn’t they make these boards work at 5v…
The ceramic aerial works I would say ALMOST as well as the PCB aerials on the ESP-01 (I pick up more access points on the latter) and the pin spacing is a pain – maybe they had something against simple 0.1” spacing! There’s an additional surprise for those of you used to the ESP-01 board, one of the potential I/O pins has to be tied to ground – I found that out the hard way. So I have no idea what GPIO18 is about but the LUA interpreter does not support it so that one ended up unused. I have an Android APP happily polling this board at high speed when needed to monitor they states of the pins and I’m sure with just a little effort I could have done much more. Will I rush out and buy more?
Right now I’m having good vibes about the ESPRESSIF AT software which now seems to work well on the simple ESP-01 boards and with the addition of control over the reset on those boards I reckon it’s possible to make a pretty reliable set of kit though I’ve yet to start considering what happens if the router dies temporarily. I would like to see some decent webserver software for the AT control set, written perhaps for Arduino so that for those installations where a WIFI access point is not practical, the board can act as a relay for several others in some kind of piconet. No doubt that will come (Update Dec 29, it looks like MQTT might do the network function – see later blog).
The pins available on the ESP-03 include VCC and ground, Antenna output, CH_PD, RX and TX and the following GPIO pins – 00,02,12,13,14,15 and 16 but see the image above right concerning GPIO0, GPIO15. GPIO16 is used for deep sleep/wakeup, If anyone has a more definitive list of what these pins are for – please do write in as there is a lot of confusing info on the web.
Update 20/12/2014: As you can see on the left I’ve also made a little baseboard for the (several) ESP-01 boards that have now arrived from China. PCB still on the way from the manufacturer – so many things to test: latest Lua, the Frankenstein code (which at the time of this update seems to have stalled a little), the Espressif AT code (new SDK as of yesterday) and this weekend I’ll be having a play with these as well as considering the options for tying this into my home controller. I’ve followed a few blind alleys here but I think I’ve some ideas as to how best to make use of these boards which with luck might event soon have handshaking (unfeasible on the ESP-01s due to lack of pins). This and the ESP-12 offer great possibilities.
Thanks to JOHN and others for the reminder about GPIO16 which I originally had marked down incorrectly as GPIO18)