ESP8285 in the Flesh

ESP8285[6]ESP8285Well, here it is – one of our readers kindly sent me chips to play with. So first things first – unless you have incredibly small hands there is no way to “play” with these with a soldering iron – but a reflow oven well that’s another matter.

For anyone wondering what this chip is – it is the ESP8266 with 1Mbyte of FLASH embedded in the chip.

So it remains to be seen what to do with this tiny chip and marvellous opportunity – clearly we need a board. Readers have kindly sent links to boards – and that’s great – except the board + postage generally seems to be more than the cost of a full, all singing, all dancing Raspberry Pi – or at least a FriendlyArm M1 + WIFI adaptor.  So what’s the point?

I have some thoughts and while I ship these chips back to Aidan in the UK to ponder  a board layout, I’ll air my thoughts here.

So to make a small board it would make sense to reduce the reset/program thing to 1 button – adding an FTDI chip would just jack the price up – so my thoughts would be the normal FTDI connection – that is a 0.1” 6-way connection with GND, N/C, 5v, RX,TD,DTR

It is quite easy in, say, Eclipse to manipulate DTR on the FTDI (a simple Python script does that and it is trivial to add it to the makefile). Other languages would do just as well. So the usual trick is to have a button you can ground, which if done quickly, will merely reset the board…. if held for a while, will force GPIO0 to ground until AFTER the reset returns to normal. IMPORTANTLY this should not affect GPIO0 after reset!! now, I like to use GPIO0 as an input AFTER power up – so it becomes a multi-purpose pin. Held low before power-up you can go into programming mode, after power up you can use it to put the unit into terminal mode.

FOR THAT reason I’m going to suggest that we forget clever reset/programming hardware  – a combined reset and GPIO0 button is not a good idea – and indeed, how often are the boards programmed?  My suggestion then is for FORGET the reset button  -and just have the GPIO0 button (shorts to ground – with a pull-up) – this gets rid of a few components – and when the GPIO0 button is not pressed – there is no connection to GPIO0 which frees it to be used for whatever purpose.

Clearly you need a regulator – feeding 5v into the unit. That needs a reg and couple of passives.

Clearly you also may wish to DRIVE something – but we don’t want a massive board on the off-chance – you may wish to drive a relay OR you may wish to power 12v RGB LEDs so my initial thoughts are – 3 MOSFETS on the underside of the board (which can be left off – and they can be hand-fitted after the board has been put together in an oven (for the chip). That way if you chose to use a relay  – put the diode across the relay and you have a choice of using a 5v coil or a 12v coil etc.

A led INDICATOR is always a good idea – but because you might have the board in WIFI AP mode or it may be waiting to connect to MQTT, a normal LED may end up having to do too complicated a flashing setup – my thoughts there would be to have the option to fit EITHER a LED and resistor OR an RGB LED – the latter can be any colour and dimmed as needed without any external components.

Ceramic antenna or PCB trace? My own experience is that the ESP-12 with it’s trace antenna is VERY good – and so much as I’d rather save board space – I think I’d put the trace at one end of the board.

This board then could end up not too different to the old ESP-01 in looks.

Pin use would work with our existing software of course – so GPIO13 would be the LED indicator, GPIO2 would be ideal for DHT22 etc. and a pull-up would be fitted on-board.

25mm square perhaps??

Comments? Thoughts?


30 thoughts on “ESP8285 in the Flesh

    1. Of better, for very little more – the standard WEMOS –

      The problem with the LITE is that it uses the 8285 which might well be a money saver for manufacturers but has on external FLASH, using instead an internal 1MB Flash – which almost takes us back in history to the ESP-01. I would suggest to anyone using the ESP chips to ensure they get 4MB of FLASH. For example my own code takes over 512K – which immediately makes OTA impossible with a 1MB device – a good reason several people in here have upgraded their ITEAD mains control boards. Other software still lets you do OTA with that amount of FLASH but I notice that the writer is modularising code to get over the fact that it just is not enough FLASH as we get more ambitious with our programs. And it can’t be down to the COST of the FLASH – with ESP-12 modules coming in at under £2 including processor, flash and board!!

    1. It’s on the way – couple of weeks or so – Chinese post.. I think wearables – not a lot of benefit otherwise – but I could be wrong.

  1. I just drew this up last night. A minimalist ESP8285 breakout. Nothing but the ESP, a 26mhz crystal, a cheap antenna and an sot23 vreg on the flip side.

    Almost all the GPIO are broken out and GPIO16 is tied to RST for deep sleep support. Top layer is +3.3v, bottom layer is ground.

  2. Hi Peter, did you see this one yet?

    Charles is a real whiz at making the esp sign and dance (color tv out?!), and he’s turned his skills to the esp8285. That tiny single layer board was talking over 400 meters distance using a cheapo ceramic smd antenna!

    He’s posted up the pcb artwork here, there’s even a kicad board file to send off to the boardhouse of your choosing

    1. You know I never thought of range testing them like that – it just so happens my neighbour has a quad coptor that knows exactly how far away it is… hmmm

        1. I didn’t say it was cheap.

          I did notice the cost but in case it was Jerry’s board I didn’t comment on it – certainly too expensive for me but different people have different perceptions of value 🙂

          1. I agree. Each to their own – my focus is on cheap – because I know how much things cost – I spent years in manufacture, I keep up to date with companies like iTead who can do a complete mains control unit for well under a fiver and I just look at some of these designs and think the guys are living in a bygone age. Aidan and I have spent FAR too much time discussing how to make a board that can really be produced cheaply but which does what “most” people want”. Not an easy one.

          2. No, no..the one in the picture is not our board.
            I know that manufacture, they have not finish the module yet.
            they only take a few photos for marketing purpose…hehe…

            ITEAD’s board is on small volume production now.
            but our documents are not ready yet.

      1. No, this one is Kris Winer’s one. It is more a prototype board produced in small quantities and soldered by hand, thus the high price tag. Kris has some very interesting boards for those who want to experiment with flying R/C drones: IMU (Inertial Measurement Unit), FC (flight controllers), and ESC (Electronic Speed Controller).

        Jerry links to, so my guess is that ITead is preparing a small and cheap ESP8285-based board!

  3. The Syntax Police in cooperation with the Obsessive Compulsive Association of Your country (OCAY) would like to point out that the possessive pronoun “its“ is written without ANY apostrophe.

    An easy way to remember this is if you can replace “it’s“ with “it is“ and the sentence still makes sense, write the apostrophe, otherwise don’t.

    The members of the OCAY would appreciate it greatly if you heeded this advice in future articles, so that they can get a proper night’s sleep again.

  4. I think this chip is not supposed to put on a regular board, but on something flexible that allows sewing into clothes, shoes or in accessories. If you put it on a board, it definitely won’t scream “buy me”. But if you think of it as a wearable mcu that could do e.g. WiFi enabled step counting, heart rate monitoring or controlling the LEDs of Jericho’s new $15,000 jacket, you may change your mind…

    1. Yup, that’s true. I didn’t miss the “wearables” part of the announcement. I just don’t think that it applies to the majority of hobbyists (Adafruit probably being the most notable exception).

  5. I have to admit to feeling that the ESP8285 is pretty much a non-event for most hobbyists. If the built-in flash had been massively bigger than what’s available at the moment it might have been different, but there’s nothing about this chip that screams “Buy me!”. I’m guessing that most people will carry on buying ESP12/13 modules and just wait for the ESP32.

    1. Well, my prediction is that someone will come up with a twist – size I would think. At the end of the day that’s the only significant benefit. For me the Flash is a bit of an issue as my code is over 512k now so that limits OTA. As for waiting for the ESP32 I should not hold your breath – I don’t think they ever intended it as an ESP8266 replacement – and it’s been quite a while since it was announced – not seeing any boards?

        1. Would agree about this device being a technical blip – as PuceB remarks, a wifi only soc will always live in a (power hungry) zombie zone. I can’t realsitically see it as wearable.

          For most of us, the future has to be a SOC chip with WiFi AND Blutooth (like the ESP32)
          Consider URL advertising by Blutooth LE gets picked up by a phone App to enable easy setup of comms and user displays on your phone – nothing needs to be programmed in that paradigm….
          …and what about this

    2. Glad you received them Pete!

      Cost, Size and Power Consumption: here are the 3 main constraints in IoT.

      The ESP8266 addressed the first issue, this one is addressing the second. If you need to embed Wi-Fi in increasingly smaller devices, you will eventually have a single-chip solution.

      The ESP8385 is integrating the Flash chip, which is a good thing in term of size and board complexity, not speaking about avoiding refurbished / defective Flash chips from non scrupulous Schenzhen grey market.

      My guess is that we will soon see smaller “ESP15” modules with shield and all important pins broken out. This module will become interesting for makers, then.

      1. At 1.99 usd the ESP8285 is cheaper than any 8266 I’ve seen.
        I agree the 8285 is probably more suited for wearable due to size but we all know that only hindsight is 20/20.

        1. Hi Jack – not sure what you mean here. The 8285 are more restricted than the 8286 with less FLASH which severely limits size of programming – at $199 you say cheaper…. check out Aliexpress – depending on conversion rates you should find a full ESP-12 for the same price – ok – a little bigger – but you cannot use those chips on their own – unless you have fairly good SMD skills so you end up with them on a board surely no smaller than an ESP-12.

          And if that antenna is so good (see straight copper line) why do ESP12s have a more sophisticated antenna…. not really sure I’m seeing the benefit – I do have some coming to me to play with – but the ESP-12 up to now is for me a very good choice.

          1. The copper line with gold finish is not an antenna. It is the footprint for a RF shield which they have not mounted in that picture. Having said that, it is amazing how well modern radios work even which crappy antennas (which is not an excuse for bad antenna design). I have a GSM module which also has bluetooth. The bluetooth feature is not required in the application. So the bluetooth antenna pad is not connected to anything on the board. However, I could still connect to the module over bluetooth from anywhere in the room.

Comments are closed.