Monthly Archives: May 2017

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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Terminal Login

I made this as a continuation of my current work with the NEO2 but there is no reason why this could not be adapted to other boards. There are also many ways to achieve the same thing i.e. colourful terminal login – this is merely a what I chose to do.

promptSo I like colourful terminals when working with little boards like the Raspberry Pi , NEO and many others.  I’ve long since gone off using the graphical interfaces (unless I’m making a media centre) – and play with the boards mainly from my Windows PC using WinSCP which gives me graphical access to the file structure and the ability to use Microsoft Studio Code (I used to use Notepad++ but that was, it seems, a lifetime ago).

Continue reading Terminal Login

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NEO2 NAS Part One

NAS BOXThis started off as a simple bit of fun to see if the FriendlyArm NAS box was any good – I had no idea it would turn out to be so much fun..  read on…

My first NAS was the NetGear ReadyNAS duo – some of you may recall this – possibly with mixed feelings – it wasn’t the fastest tool in the box and mine was one of the earlier ones which had the peculiarly stupid “feature” of not turning on until you pressed a button -  how dumb is that?

Continue reading NEO2 NAS Part One

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NEO REBOOT

I have covered the FriendlyArm NEO and NEO2 boards here before now and generally been in favour – but for one little item in common with many other boards – little or no IO support – well, that just changed. Read on…

With no apparent way to get to the IO on this cute little board, I promised I would write to FriendlyArm and ask for WIRINGPI and that I did. In the meanwhile if you take a look at the relevant blog entry you’ll see I made a start at using GPIO the hard way and even found a WIRINGOP (OP – Orange Pi) variation that would do basic IO if you could guess the right IO pins, but that was about it.NEo2

Continue reading NEO REBOOT

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Big Nextion

ITEAD DisplayQuite a while ago now I did a project based on the little Nextion displays, resistive touch-LCD displays which run on serial commands and come with an editor to make simply touch displays for even the simplest of micros.

Well, that project has proven to capture a lot of interest and I have one of those displays running 24-7 in a holiday rental property – and it has been doing that for a couple of years now.  I’ve not done anything new with the displays for a while but this morning, a new generation display turned up for me to take a look at.

The NX8048K070_011C is a new 7” Enhanced HMI Capacitive Touch Display complete with case (also available without the case) from Itead – the company who also produce the Sonoff units we’ve discussed many times in this blog. Continue reading Big Nextion

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A Quick Plotly

Some time ago I wrote about HighCharts – a wonderful set of Javascript tools for doing graphs – and I gave an example of getting the graphs into Node-Red.  I’ll not repeat that as you have the link above.  At the time I’d not added in databases, I’ve since made some VERY simple code to bring in the charts from SQLITE -  I have to say it isn’t the fastest code in the world so I won’t embarrass myself by replicating it here. But at the time, my only limit was Node-Red Dashboard – there was as far as I could tell no way to get full screen or anything like it on a PC  -  until I took the plunge today and ask the right people – turns out that you can set an individual page in Node-Red Dashboard to WAY past the normal 6 blocks width simply by altering the size of a GROUP used only on that page.

Continue reading A Quick Plotly

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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.

Continue reading ESP8266 Code Update

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Uninterruptible Supplies

Need a power supply with battery backup that shuts off your PI or similar gracefully when the battery gets low and starts up when the battery  recovers? I’m sure most of us who play with the likes of Raspberry Pis and other SBC boards as well as other devices, have looked at uninterruptible supplies at one point or another – I often use the little battery powered chargers you get for phones – and until recently I thought that was a universal solution – having powered my Pi in Spain for many months now on one of these and we get awful power cuts there – no problem.

Latest update 23/07/2017

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