Category Archives: ESP8266

The Wall Display

ESP8266 Wall DisplayI’ve just spent time working on my hallway wall display, the amount of which would be considered commercial suicide. Good job it isn’t commercial.

Of course I’ve not just been working on the pretty colours – I’ve revamped the control codes for the ESP8266-driven controller twice, discovered and fixed an OTA flaw in the code, re-hashed the Node-Red driving code, found and fixed countless other bits and pieces… and in the process taken pause for thought as to why I ever used the Dark Skies Node… you know – in other words – pretty much revamped everything just to improve a simple display.

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Simple Scope

SPIYou may have noticed that I’ve been working on my ESP8266 home control software (see the updates elsewhere along with new diagram), specifically upgrading and adding to the number of OLED and LCD displays I can handle, either by I2c or SPI.

I’ve been doing a lot of optimising and simplifying – for example with SPI – assuming that there will only be the one SPI device at once on an ESP means you don’t need the CS line which can be grounded.  But there’s more….

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Icons

QD-TechIn case you were wondering – no, I’ve not gone off the boil, I’ve been quietly beavering away on my ESP8266 code since deciding to abandon the old ESP-01 and adding fonts for displays. Right now I’m focussing on the QD-Tech boards – 120x160 but I’ll eventually migrate the use of the various icons to the other displays now that I’m not terrified of running out of space.

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ESP8266 Home Control Update

As the blog entry on using my home control code ROMS for ESP8266 is filling up and of course as much of the information is now dating I thought I’d do a new blog to bring everyone up to speed and move the conversation to this blog entry. The good news is  - the code is now running under SDK 2.1.0 – i.e. bang up to date at the time of writing.

Home Control 2017

Firstly – yes, everything works – but the procedure for flashing ESP-12 etc has changed ever so slightly. I have updated the binary files to run on Espressif SDK 2.1.0 and updated the RBOOT code I use for OTA (over-the-air updating) to the latest version.

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ESP8266 Lessons Learned

ESP-01The Trip: As regular readers may know, early in 2016 I worked in Spain on a contract with some great guys to analyse information from ESP8266 chips. Without going into any commercial detail, this is what I brought back from that trip as well as other lessons learned since then.

The scenario: The tests were done on a series of ESP-01 WIFI micro-controllers  in a rural environment, initially with a bank of 40 ESP-01 boards. These were powered by a single 20 amps 3v3 power supply. Yes, a switched supply. The boards were mounted on Vero-board and power applied. No linear regulator to smooth out the crap ( I would normally run 5v switched and a linear 3v3 regulator on-board for each device), lossy tracks on Veroboard, signals interfering with each other..  except it DOES get worse - read on.

The Place: The location we conducted our tests was off-grid, relying on solar power and a generator - and the weather most of the time was cloudy - that meant at regular intervals the remote generator kicked in and when it did a couple or so mains cycles were lost as the set-up there uses a combined inverter/charger. The result of that was that at regular intervals, the router reset.

boardsAside from actual power cuts you don't get much worse than this.  At first when we switched on the boards - which are running a modified version of my home control software which is in turn based on TUANPMs MQTT code with a boatload of stuff added and a lot of tweaking over time, only some of the boards would report back. A quick check of the router revealed that by default it only allocated enough room for 32 connections on DHCP. That was quickly doubled and lo and behold, all the boards logged in by MQTT to the PC (running Node-Red and MQTT and firing off data to a database).

Useful outcomes: Well, any thoughts I may have had concerning reliability completely vaporised this last 2 weeks as day after day our little bunch of 40 boards (not even all from the same supplier as some were blue, some were not) just sat there constantly delivering information. This was soon increased to  a wopping 120 boards without issues.

So if you're just starting up with ESP chips - bear the above in mind before jumping to conclusions about board reliability. The boards used in the test, running as I speak, were the early 512K versions, today I always use ESP-12 boards in my own projects as they have eight times the amount of FLASH which means OTA, big programs (up to 1MB of C code (that's a lot)) and in the case of the "F" version arguably better antennae.

I sometimes hear of people complaining that once programmed, some ESP boards go into a loop at power up - and I've recently had this happen to me TWICE. In each case I had extra bits and pieces attached and was running the board off the FTDI - again in each case, putting proper 5v onto the boards immediately resolved the "problem". FTDIs vary a lot in their output and voltage.  While it is tempting to use them to power the ESP (or indeed the micro-usb connector in some cases, straight off your PCs USB - the time will come when this causes trouble and now you know the answer.

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ESP8266 Code Update

The code that forms a series of articles on this blog has now not been updated for some time – simply because it “just works” and has been doing so reliably for many months. However, I’ve been wanting to add bits to it and my problem was I was running dangerously low on iRAM. This would not affect the stack or reliability but would just stop me from continuously adding code.

Well, thanks to Espressif that is now history. The latest Esp8266 SDK, released just days ago, fixes a number of things on the ESP8266 – you can find the SDK here – you will need it if you wish to compile code but of course ROMS are available as usual.  The upshot for me is the return of nearly 800 bytes of iRAM which is something of a breath of fresh air.

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Cheap NodeMCU Boards

ESP8266 NodeMCUThis could be the shorted blog I’ve ever written! We’ve been talking about ESP8266 recently and as I was running out of boards, I sent off for some of these from AliExpress – my favourite store next to Ebay.  At a total cost of just over £3 they had to be worth a go.

So on the LEFT you see the reset button – on the right you see the FLASH button – this might indicate that normal Arduino-style programming doesn’t work… so I put it to test with a sample BLINK program.

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ESP12S

ESP12SI’m looking forward to trying out the new ESP12-S – this one apparently has a better antenna – and by the look of the schematic (see page 15 – thanks Alexander) the resistors on reset, GPI))0,2 and 15 are already there.

That should simplify layout somewhat!

ai-thinker.com - www.ai-thinker.com/uploadfile/2016/0909/20160909073755898.pdf

Hmm, board layout with 0.1 pins, 3v3 reg with decent heatsink area underneath, maybe 3 mosfets…

So this should work with existing layouts. I’ve kept back an IoTBEAR adaptor and ordered a couple of these from Ebay sub- £2 each.

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Microwave for the Weekend

tmp2DA0If you read the blog about the Maker Faire, I just came back with a bag of goodies and one of them is a microwave movement sensor.

Not the two-board solution I discussed a while ago that never really worked – this is a small, neat single board called an RCWL-0516 and here’s a Chinese link though if you get in touch with the fellow I mentioned at the Faire where I got mine – ABX-LABS (Ebay shop) he might have them. About £1 anyway.

So this board has 5 wires and not a lot of information out there, some of which is in Russian. I did found out enough to know that this unit is oscillating at around 3 Gig and you only need to use 3 of the 5 wires!

The unit will pick up movement up to 7m away and in the right circumstances can see right through wood! No silly comments about being irradiated please.

So I set it up on my bench, the 3 wires of interest are ground (obviously) VIN and VOUT. Stick 5v on VIN (will not work on 3v3) and a LED on VOUT – and you’re done – it works.

Well, that was easy and of course it WAS too easy. I took the board and applied it to one of our ESP8266 boards which have 5v – and took the output to Pin 14 which in the case of my software, is a de-bounced input which can send an automatic MQTT message on change.  Job done – except – it would not work. It seemed over-sensitive but after more careful checking – it really wasn’t taking too much notice of movement – instead triggering fairly regularly ALL ON IT’s OWN!  I tried putting a cap across the power, I tried putting a cap across the output – all to no avail.

In the process of having a gripe with Aidan that we’d been ripped, I put the board on my standalone test to show him it working – and decided to route ground and signal back to the ESP – it worked perfectly – then it twigged -  ESP8266 boards are prone to putting spikes on the power lines when transmitting!  I put a 10r resistor in series with the power and a tiny 330u 6v cap to ground at the Microwave board end – problem solved.

If you want to do something clever, the 16 pin logic chip – I stuck a scope on it and pin 12 gives off some interesting analog stuff!

In terms of sensitivity it pretty much works 360 degrees though supposedly it is most sensitive on the component side of the board direct on.

I spend half of my time waving my arms about at the normal room IR sensor to keep lights running – this I think will be MUCH better.

Have fun.

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