Category Archives: ESP-12

INA219/ESP8266 and Node Red

tmpB2D1In a previous blog entry we were playing with the INA219 voltage and current monitor. Here I team the little board up with the ESP8266 and Node-Red.

In this entry, I have teamed up the INA219 with my ESP8266 code which already has a driver in for this chip and also has support for the SSD1306 – hence, thanks to MQTT, this little combined chip can easily show the current status on the on-board display and also show it on a Node-Red dashboard in gauges and also a combined graph.

Please note that I have updated the ESP8266 code (v2.3.15) and changed how this works as I ended up writing way too fast to the device… this code works.

Power MonitorOf course that’s how I’ve done it – armed with info you can do any variation you like. I’ve set the graph limits here to 6 volts, I guess it would make sense to set it to 30v.

I’m also using a 1 second inject node, perhaps something more flexible and externally programmable would be better – in which case you could have different graphing speeds. Nice for checking battery charging?

As my ESP8266 code (documented on the blog – see right menu, ROMS available, recently updated) already does all the display and INA219 handling, everything was done in Node-Red.


Power Monitor

Here is the code for “Process Chart”

var ina=JSON.parse(msg.payload);
var msg1={};
var msg2={};
var v=Math.round((ina.voltage/1000.0)*100)/100;
var a=Math.round((ina.current/1000.0)*100)/100;
var w=Math.round((v*a)*100)/100;

msg.payload=v; msg.topic="voltage";
msg1.payload=a; msg1.topic="current";
msg2.payload=w; msg2.topic="watts";

The injector node has a topic of ina219/toesp (assuming you set the ID of the board to “ina219” of course) and a payload (string) of:


The 1 on the end implies a 64 pixel high ssd1306 display attached, a 0 would imply a 32 pixel high display and no parameter would assume no display and simply send the information out. Initialisation of the INA219 and optionally the display happens at first use – no need for separate init.

I’ve now added range adjustment – you MUST have the latest node-red-dashboard for this…

return msg;

In the case of setting the maximum range to 6 – the payload for that button (drop down and select JSON) is {"ymax":6} – have as many as you want!!

And that’s it  - simples…

I’ve not shown current here as I need to lower that LOAD resistor on the INA219 but you will normally see voltage, current and power in that graph! Once I figure out how to correctly reprogram the chip I’ll add that into the ESP8266 INA219 code.

I have some 0.025R resistors on the way but from China so it’ll be weeks. Meanwhile of course this is perfectly usable.

The first version of the software proved unreliable and so anyone who first looked at this may have noticed I've updated the ESP software. The current version I have sitting on a window on my PC.

It has now been running at 1 sample per second for the last 96 hours without a glitch. At some point I'll add disk (sqlite most likely) logging - though in Node-Red that is simple enough to do.


ESP8266 Lies and Deceit

tmpCE60It never ceases to amaze me when looking through Ebay, the level to which companies or individuals are prepared try to mislead the public or at best are simply unable to form sentences correctly. Some even tell outright lies.

Let’s take one of my favourite subjects, the ESP8266 boards. Way back in the past, ESP8266 life started off with the ESP-01 module, comprising an ESP8266, 512KB FLASH and most of the connections NOT brought out. Being surface mount, only the most agile could solder pins to get the extra outputs – but – we were all new to this – and what a bargain, for just a couple of pounds you could have a crippled ESP8266 and actually turn things on and off via WIFI.

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The Script and RPI 3 Update

Having started putting together “the script” a long time ago, long before the Raspberry Pi 3 came out – and having developed it to handle a wide range of boards and scenarios including of course the Pi3, I found it interesting to return today to installing “the script” on the Raspberry Pi 3 – and of course I wanted to ensure that nothing had changed recently which might stop others doing the same.

Continue reading The Script and RPI 3 Update


Home Control 2017

Introduction (Latest update October 08, 2017)

HomeSick of reading about other people’s home control? Want to make your own? Got some electronics and software experience? You’re going to LOVE THIS! Rock-solid home control, flexible, low cost, DIY.


Home Control 2017

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A Flashing ESP Chips Surprise

Well, you could have blown me away.  Tonight was making a little relay controller for the hot tub using a WEMOS board and relay board. I carefully soldered them together and plugged them into a USB connection on my PC, as I’ve done thousands of times.

Also as I’ve done thousands of times I flashed the board with my ESP8266 standard software which I have down to a single button-press in Eclipse.

Continue reading A Flashing ESP Chips Surprise


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.

Continue reading ESP8266 Home Control Update


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.


Weather 2 Board and ESP8266

tmpE044NOT the cheapest board on the planet, I was handed a couple of these little boards by a friend this weekend.. the weather-2 board.

The board uses 2 i2c chips – the BME280 which as you may know is a miraculous little chip offering temperature, humidity and pressure readings all in one chip. I already support that in my ESP8266 code. Nothing new there and the chip works as expected when plugged in using this module.

What this board brings to the party is a chip I was previously unaware of – the si1132 – which in one chip offers readings of visible light level, UV level and IR levels.

The original library for this used floats and I’ve reduced that down to integers – looking at the variations I doubt I’ve affected accuracy at all – and these now come in the form of I2c commands in my ESP8266 code..




Assuming the board is attached (or a board containing that chip that works at the same I2c address) – you can grab readings from this chip no problem.

I could envisage one of these outside – in a cover that protects it from the direct light and direct heat of the sun, offering all 6 readings – handy for lots of things.  Or maybe you just want an alarm when you’ve had too much sunbathing – I’ll leave it to others to figure out best uses.

Makes a useful addition to the home control project. Source of the ESP8266 code available as are ROMS.


ESP8266 Meets Arduino via I2C

If you’ve been reading the blog regularly you’ll know I added I2c to the ESP8266 code some time ago – that is, the ability to send an I2c message either to read or write – originally intended and still working with cheap I/O expanders – so you lose 2 wires (GPIO4 and 5) and gain another 6 or 14 for one or two I/O expander boards.

Well, I’ve updated it as of tonight.

Of course, ESP12 talking to Arduino is nothing new but given what we’ve built up here with the ESP boards and Node-Red I thought it might be useful to have the option to expand further.

What a few hours ago seems like something in the distance – well, it is done – and it works – and it has LOTS of potential. Read on.

ESP8266 and Arduino and I2c

What you see above (the FTDI is just stuck into the ESP8266 board for power) is a 1284 Aiduino boards flashing lights  - controlled by MQTT – that is, the ESP12 board on the RIGHT is taking in the MQTT and sending commands via I2c to the 1284-based board and to the little red expander in the middle (on the same 2 pins).

Hence, I’ve spent the day working on the I2c code adding the ability to send multiple byte parameters and to receive a byte (I could have made it receive multiple bytes but for simple control a byte will do).

ATMEGA1284The next step was to set up an Arduino – or in my case specifically an ATMEGA1284 chip to talk to the ESP – hence giving us the ability to control Arduino ports via Node-Red.  Now as yet another blog entry here will testify, you can of course connect (now that the node is fixed) an Arduino directly to the Raspberry Pi in charge – but puts too many physical constraints up.  I had no intention of developing Firmata on the ESP – and so a simple i2c protocol was develop and SO much more can be done.

Right now I have an ESP8266  on the bench with a 2-wire I2c connection to an I/O expander – and an Arduino-type board using the 1284. I can talk to both from the ESP (and hence from my Arduino wirelessly via MQTT) and can control the following:

  • Any pin as an output (and PWM outputs where appropriate
  • Any pin as an input (and analog inputs where appropriate)

So first things first – I used  the Atmega1284 simply as I have loads of them – both DIP40 and surface mount in our little AIDUINO boards. The 1284 has twice the RAM of a 2560 and is easy to use. However this would work equally well in a normal Arduino or in the massive 2560 boards.. the only difference being which two pins are used for i2c. The red chart above, shamelessly stolen from ManicBug’s website shows the pins (in parentheses the numbering system I use).

So in the ESP8266 (grab the latest ROMS or SOURCE) I have a simple method of communication which can be used by MQTT or serial. The format is similar to that used elsewhere in the home control system.

i2c:  device, return, param1, param2, param3, param4, param5.

Not all parameters are needed.

So – to talk to an i2c expander sitting as device 39, connected to pins 4 and 5 of the ESP board…


device 39, no return value, send out 3 (which lights up the bottom 2 LEDS.


This returns the value in the port expander.  this is covered in two previous blogs.

So what has changed is that the code can now send out multiple parameters – and optionally receive information back.


The above sends out to device 8, expecting nothing back, type 1 means set a port bit, bit 20 in this case (see red table above) – to 1.


Above – device 8, 1 means return a byte, type 4 means read analog value and port number is 30 – the instruction will return the value of the analog input.

1 is digital out, 2 is digital in, 3 is PWM out, 4 is analog in – you must use appropriate ports – not all are able to handle analog in or PWM out… and you don’t have to worry about port direction setting – this is checked before any operation and set.

There is SO much more potential here but only so many hours.  I will likely make the settings for outputs non-volatile at some point – and add in all manner of device monitoring and probably also make use of the multiple serial ports on these devices.

For now that’s not bad for a Sunday session.  If you’re seriously interested I’ll make the Arduino code available but right now it is highly volatile – but it works!!


Home Control Updates

For those following the home control project including the ROMS for ESP8266, I’ve made several changes in the last few days including a new uptime command {uptime?} returning a string of the time since last reset/power-cycle. Also added that to the debug output – also fixed a couple of minor RGB issues. Source code now works with very latest SDK from Espressif

If none of this means anything to you see:


Blowing the Home Control 2017 Code

Hackitt and BodgittThis is for the people who’ve been trying out my software (or thinking of trying it out) on the ridiculously cheap (£1.40) but very reliable, powerful and comprehensive ESP12 WIFI processor board and those who’ve gone ahead and gotten some boards we made – all referenced in earlier blogs. For the latest on how to FLASH the chips see this blog update.

Essentially the assumption here is that you have an ESP-12F-based )(or variation such as ESP-12E) board of some description and that GPIO0 is used as a programming button (held to ground to program etc) – and also as a web setup button.

Continue reading Blowing the Home Control 2017 Code