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Neil Kenyon's Blog

33 posts
The Problem   A few days ago I discovered that the battery powered, ESP8266 based temperature monitor in one of my greenhouses had stopped transmitting data ti my local web server. When I investigated further, I found that the battery was flat.   This was a surprise, as I hadn't received any emails warning me that the battery voltage was low. The method I use has worked totally reliably since I first implemented it almost 2 years ago, as described here:   Send an Email from ...
INTRODUCTION   This is the third part of a series of blogs devoted to programming the Raspberry Pi pico:   Adventures with the Raspberry Pi pico - part 1 - Describes setting up the toolchain and building all the examples using the command line   Adventures with the Raspberry Pi pico - part 2  - Tries to understand some of the processes covered in part 1   In this blog I will try and describe the processes necessary to configure and use Visual Studio to build the exa ...
Introduction  At the end of my previous blog:  Adventures with the Raspberry Pi pico - part 1   I said:   "Next Step:" "Learn how to modify the blink source file - to blink2 -  build/compile it and then flash the pico with the modified file."   In fact, I need to understand what I've actually done - I was just following someone else's instructions. Many people reading this will already know, but maybe some won't! I hope it helps them!   Although I don't ful ...
My pico arrived on Monday, 24 January, but I had other things that I had to do, so I resisted starting on it until Tuesday, 25th.   I'm documenting everything to make sure that I understand what's going on!    The Easy Bit!!!  Open the package and have a good look - very easy!!!   Follow the instructions in: https://www.raspberrypi.org/documentation/pico/getting-started/  in the tab labelled "Getting started with C/C++   Plugging a micro USB plug into the so ...
I first spotted this large milliAmmeter in the window of an Antiques Shop in Castle Donnington, Derbyshire, a few weeks ago. Unfortunately the shop was closed, but I decided to go back for a closer look when the shop was open.   I found the shop open last Saturday and had a good look at the instrument. As can be seen  against the e14 little bue man, it's quite large, typical of the instruments I can remember being used on the teacher's/lecturer's bench many years ago! I suspect it d ...
Just before Christmas last year, my ISP offered me a deal whereby I could have my broadband connection upgraded to twice the speed and actually pay a little bit less, provided I signed up for another 18 months contract. The deal also included a new router. I have been satisfied with my ISP and the price was competitive so I signed up,   The router arrived, the switch over occurred and my desk top PC (cable connected) was back online and looking good almost immediately. I then went through ...
My previous Blog - Over the Air (OTA) Programming of ESP8266 - Part II - ended prematurely, because I clicked the "Publish" button by mistake!!   The Blog ended at the point where I had just shown the last segment of code inserted into the sketch to enable a full demonstration of OTA updating from an HTTP Server.   Here is a recap of the sketch functionality:   Include the necessary libraries Define necessary constants, including current Version Number Start the Serial Inter ...
OTA Firmware Updates using an HTTP server   In my previous Blog:Over the Air (OTA) Programming of ESP8266 - Part I , I described how to update ESP8266 firmware OTA, using the Arduino IDE to connect to the ESP8266 via a "network port". I pointed out that this is of no value when needing to update a device which spends the vast majority of its time in Deep Sleep (conserving battery power).   The HTTP server approach has the existing firmware on the device capable of updating itself fro ...
INTRODUCTION   The following summary is taken from the the ESP8266 package documentation:                   https://arduino-esp8266.readthedocs.io/en/latest/ota_updates/readme.html   "OTA (Over the Air) update is the process of uploading firmware to an ESP module using a Wi-Fi connection rather than a serial port. Such functionality becomes extremely useful in case of limited or no physical access to the ...
Where am I?   At the end of my last Blog, I had a semi-functional Arduino IDE/ESP8266 development environment. It would sometimes compile a sketch correctly and sometimes it would fail to compile the same, unchanged sketch, usually with errors relating to (untrue) multiple library references. I have wasted hours attempting to sort this out and failed miserably.   However, because the environment would sometimes behave, I decided to satisfy my desire to make some progress with develop ...
WHAT DID I DO?   Wednesday 27 November 2019 was cold, raining and generally miserable, so I decided to try and get back to some project work. I hadn't done any coding with my Arduino IDE since about May this year, so I thought I'd better check for upgrades before doing anything else........this turned out to be a bad mistake because I didn't make a note of the current version numbers of the IDE, the libraries I had installed and the ESP8266 package, so when it all seemed to go wrong, I did ...
When the final long term test of power consumption of my Wemos d1 mini temperature monitoring system was complete:   Power Consumption of a Wemos D1 mini ESP8266 - Long Term Test 3   I decided to try recharging the battery - from a mobile phone charger - whilst the Wemos d1 mini was still connected, so that I could monitor the charging process.   After charging the battery for just over 2 hours I had to go out, leaving the house empty, except for #sadiethecat1409 (Instagram). ...
Having returned from my holiday in the winter sun , I removed the battery from its holder and set about fitting the XH2-2.54mm female connector to the battery holder leads.   I then modified the sketch to reduce the drift in the sleep time which is evident in the chart from Long Term Test 2, repeated below:     I checked the battery voltage and was pleased to see that it still showed 3.74 V on my DMM. Rather than charge it, I decided to reconnect the Wemos d1 mini system and s ...
Recap  In a previous blog:  https://www.element14.com/community/people
eilk/blog/2019/02/17/esp8266-power-consumption-further-studies  I observed that the power consumed by the Wemos d1 mini during deep sleep was pretty negligible - about 22.7 mAh over a period of 100 hours, including the Serila-USB interface and the resistor chain used to connect the battery to the A/D converter. I concluded, therefore, that the majority of the power consumed was during the actual sketch execut ...
neilk

Send an Email from ESP8266

Posted by neilk Feb 22, 2019
Background  In previous blogs, I have described my investigations into using an 18650 3.7V 2400mAh battery to power a Wemos d1 mini ESP8266, via a Wemos battery shield, which plugs directly into the d1 mini, just like an Arduino shield.   While waiting for my latest long-term power consumption tests to complete, I wondered if it might be possible to send an Email from an ESP8266, to alert me that the battery voltage is reaching a critical level, or perhaps, just to confirm that the b ...