Category Archives: General

INA3221 v INA219

tmp19F7Voltage and current monitoring

The INA3221 or rather one of the boards based around it, allows for a single power input and up to 3 power outputs –each monitoring voltage and current and all done via I2c.

You can (almost) think of this as a triple INA219 – the bidirectional current power monitor. If you recall, a little while ago, I added the INA219 to my ESP8266 software. I thought the INA3221 board might be better than three of the INA219 boards – but read on…

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A busy Week

It has been a busy week this week – with lots of new things happening.

Firstly, there is a brand new update to the RFLINK software, IMHO the best software around for decoding and transmitting signals for a wide range of RF devices – such as weather stations and remote controls – in my case using 433Mhz.  See the short video update I did on this one.

Here’s a link to a blog entry I wrote months ago on the same subject. tmpC114Then I’ve been working on the DPS5020 and DPS3003 power supply boards which have provided HOURS of entertainment.  I’ve spoken with the designer and I think this stuff has a good future because of the kind of direct support they are keen to give – and because the stuff just works. In a couple of weeks there’s a new board from the same source and when my new scope arrives I’ll be using that and the load tester to give it a hammering.

I’ve had a play with my little EM125 pocket (well, large pocket) oscilloscope and in the process of playing with these two, discovered the need for a decent signal generator and dummy load – both of these are on the way and will be covered in the coming weeks – along with some other exciting incoming stuff like a new 3D printer and a “proper” desktop scope.


MEANWHILE I’ve not gone off the boil with the uninterruptible supply, FAR from it but Aidan and I have been waiting for a PCB to turn up. It came earlier this week and we’ve been getting that working – of course, as you might expect, in the process of doing that we’ve thought of better ways of doing things, so the present PCB is going in the bin and a newer, smaller, better design will be forthcoming, most likely before Christmas.

Oh and not to  forget the new Alexa feature – using it as an Intercom – that is MARVELLOUS.

Lots happing in the next few weeks….so make a note to look in – or better, if you’ve not yet subscribed to the newsletter on the right panel of the blog) – please do!

A quick thanks to all of you who feed back constantly on the blog and on my videos and for all those who provide new ideas and new links – what a great time to be interested in technology.


INA219 IC2 Added to ESP8266 code

tmp9EC4Just a minor addition to my ESP8266 code – the INA219. Set to 32 volts, 2 amps by default, this i2c addition works with the cheap 0x40 addressed boards – I found them as low as under £2 – these little wonders can measure high side voltage and current !

So in a typical solar situation you might attach the ground to the board – and use it’s 2-way terminal to break the high-side output to your load.  You can tell the incoming voltage – and via a 0.1r resistor on the board, which leads to VERY low voltage loss – you can read the current. You could of COURSE parallel another 0.1r resistor onto the board to double the current etc. I will be trying all of that soon.

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Nano I2c Peripheral

Nano deviceMy “nano peripheral” started life as a simple attempt to expand the ESP8266 by making use of the IO on a really cheap Chinese board, an Arduino Nano equivalent Chinese £1.20 rip-off (After all, any Arduino is basically little more than an Atmel chip with reset and power circuitry and a “bootloader”).

UPDATE: Now working on IR – receiver already tested – see experimental version further down…

The idea was to build a dirt-cheap I2c peripheral, suitable for use with my ESP8266 code but now, with improved access to i2c on various boards such as the Orange Pi Zero (2 i2c channels), FriendlyArm NEO, M3, Raspberry Pi and others (see blog entry on i2c) it makes sense to look at this for general use – and with a widened range of capabilities.

Regular readers may recall some time ago I was buying all sorts of parts – A/D converters, port expanders etc. to help with my solar monitoring – and so some time ago I had a shot at making an I2c peripheral using an Arduino Nano…

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The TOMO Power Supply

TomoWell, I started to make a video of this thinking it was going to be a great new uninterruptable supply. I’d listened to others, I’d read the spec (or so I thought) and this was to be the new saviour of battery supplies.

The TOMO unit comes in different sizes, I chose the 3-battery solution. I bought mine from AliExpress.  It has a USB input and 2 USB outputs and can power up to 2.1 amps in TOTAL (2.1 amps out of one output OR 1 amp out of the other – must use the same chip as everyone else).

It is nice looking and comes MINUS the batteries and hence is cheap.  You can use one battery or more – either way it still acts as a power supply.

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I2C For Everyone

There was a time in the distant past (in my case this morning) when running I2c natively in Node-Red on anything other than a genuine Raspberry Pi was a nightmare. Not any more.

So in a recent blog I’ve covered a pair of Node-Red nodes which allow GPIO access in Node-Red on a variety of boards using the underlying ONOFF library (which loads automatically when you get the nodes). And that’s all sorted now – GPIO for all – lovely. But what of the exceedingly useful I2c?

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