Waste not, want not!

9 August 2020

I was so impressed recently when I found a mini hi-fi system that a neighbour was throwing out and came across the following video post that tells one how to trick a car’s cd-player into accepting an auxiliary input and thought that I could stream Spotify through this mini hi-fi system. (Note: always switch off the power and disconnect the plug socket before attempting this).

There were however a few problems when I tried this with my newly “acquired” hi-fi unit:

  • The CD player on this unit was clearly the reason it was thrown out in the first place, even though the radio still worked, it was older an Analog Radio, not the newer Digital Radio, which is abbreviated as DAB+. This older form of radio can be scratchy depending on reception etc.
  • The unit had a tape player which have long since become obsolete.

I thus set about finding the “service manual” on the internet by looking for the model number which is usually found on the back “nameplate” of the unit and then searching for that name and service manual on the internet. You can see this nameplate in the first image on this post. You have got to love the internet and what is available on it!

I then had to look for the CD signals on the circuit diagram for the left and right channels on the various connectors, on this hi-fi unit these were marked C/R-in, C/L-in and D-GND. I bought a good quality auxiliary cable and cut it in half. I exposed the red (right channel) the white (left channel) and the shield / signal ground (“earth”). I then soldered these three conductors from the auxiliary cable to the purple-coloured points (shown on the diagram below) to the nearest solder points on the printed circuit board (PCB) by tracing them from the connector numbered CNP303 using a multimeter on the “buzzer” setting (continuity tester). The CD player had an issue so the sound that came from connecting to these connection points was way too feint. I then decided I’ll rather connect to the more generic signals which come from either the CD or the Cassette Player (abbreviated as “CASS” on the circuit diagram) or the Radio (abbreviated “RAD”). These are thus the yellow-coloured points on the circuit diagram named L-OUT and R-OUT, below:

As per the instructions in the Youtube video if you use the CD-player you have to “play” a blank CD in the CD player. When using the cassette player you just have to push the Play button and Viola, it works! High quality digital music using the amplifier and great speakers from a hif-fi that would end up on the landfill. I gave it a new lease on life! Sustainability at its best….

There was a bonus. Spotify allows one to have an old mobile phone connected to the same Wifi as your usual mobile phone and then allow you to direct that phone to play your music. I thus used my old mobile, connected to the same Wifi router as my current phone and then with the Auxiliary cable plugged into this old phone I am now able to stream great music to this old phone. Sorry but that was such a great revelation for me. I also now have a great use for old mobile phones, I can literally find an old radio/cassette player/CD player connect that via an auxiliary cable (as above) to an old phone in every room in the house and with these connected to the same Wifi network. I thus have a museum of old technology serving a new purpose – bespoke music in every room with guests connecting to my Guest Wifi network, then able to stream their own choice of music in whichever room they find themselves. This is truly not wasting older technology, I am just repurposing it…..I love it, I hope you do too?!

Old museum-piece: CD-player/Tape cassette player and Analog radio, repurposed to work with Spotify streaming and have any guest send their choice of music to this old Wifi-connected mobile phone

This was one of the more gratifying projects for me, as I feel it improves people’s comfort levels using technology and simultaneously saves the planet at the same time, without costing a cent!

My old Samsung mobile phone is called SM-G9201 and is the device in my study which can be connected via Spotify by anybody on my guest Wifi network or even by me using my current mobile phone

Also, look for the iHeartRadio App in the relevant app store for the operating system on your phone and then you have great local Australia radio stations to listen to 👍

iHeartRadio App

I loved this project so much that I took an old car radio, the Sony CDX-S2210S and “hacked” the output CD signals so that I could use this in my pool box as an entertainment area, sound system for around the pool. Again I found an old mobile phone and installed Spotify whilst including this phone within my family group. It obviously is connected to my guest wi-fi network.

Downloaded the Sony CDX-S2210S service manual and found these three points on the printed circuit board to solder my auxiliary cable to.

A bit of a trick with this CD player is that it generates an error signal if you place a blank CD in the player. In this instance you actually have to use a playable music CD. The radio then attenuates the output from the actual CD player in favour of the hacked Aux. input signal. My wife had a coniption when the auxiliary cable disengaged out of the cellphone due to its cover messing with the seating of the connector and it played the CD rather than the Spotify signal. I may actually superglue the auxiliary cable into the mobile phone headphone port to prevent this from happening again 😜.

The auxillary cable soldered to the respective points on the PCB board (I again used the continuity tester to “buzz” the pins from the connector to the best solder points)

Just being able to repair any old machine using Arduino controllers is a great way to save the planet and save heaps of money, just read how a business card machine was repaired using a Arduino Mega 2560…so cool:

Figure machine with $200 of kit

Not all robots are equal

20 June 2020

You definitely pay for what you get with automation. I bought a 3-in-1 mop/vacuum/broom which was supposed to be all of that and have LIDAR and be able to self-dock and recharge. Well the fellas at:


These folks are in the business of scamming people and caught me out. You will see the video on their site which advertises their product as having all these features and yet it has Velcro tags on the bottom to which very thin soft cloths are attached and these are then dragged across the floor. It came with about 30 of these replacement cloths. It does have a piezoelectric sensor in its “nose” that detects it bumping into something and then has a randomising algorithm which causes it to change direction, quite successfully. This algorithm and owing to its small dimensions, allows it to get-in under tables and chairs and cabinets and attracts “dust bunnies” to that cloth. A human would need to get down on all fours with a conventional vacuum machine and a fine nozzle to reach those places.

The concept is worth about $AUD 5-$10 and I would pay that for it, provided it didn’t get it self struck on anything that doesn’t activate the sensor. That would be things less than, 5mm in height. It even gets itself caught out in grouting grooves on tiles when there is a lot of water on the bathroom floor. The fellows at keithlily (whom I later discovered our out of Azerbaijan, have a great marketing and delivery businesses model but just aren’t honest with their product). They will no doubt, not be a sustainable organization. They will constantly have to change their cover to keep duping people like me by over promising whilst also under delivering.

It did however get me thinking about what is now know as general purpose technology (GPT) and the specific version of this that is robotics. ABB have incredible robots that can do amazing things in a production line, even allowing for full customisation of each product manufactured. Boston Dynamics have created robots, with a level of realism, that defies what many thought possible just a few years ago. There are also amazing autonomous vehicles like the various Tesla models and the list goes on. On an affordability scale though, only the flight controller is at a scale of sophistication and cost that can be considered GPT, that is the flight controllers in drones. In pondering why that is, I realised that the more expensive automatic vacuum machines are only slightly better than my $USD 29.95 excluding shipping, light-touch, kiddies toy “robotic” broom. We had one from Roomba back in 2012 costing $AUD 350 and it kept getting itself stuck. I have no doubt that these have improved substantially since then, but still think that the performance versus price is still not compelling. This design needs a rethink. The flight controllers in drones are however GPT and have the right price versus performance proposition as I explain in the video below:

YouTube Video

The link to the scammers site:


If you like my efforts, either buy one of the affiliate product kits or buy me a coffee, it keeps me going!


So this got me thinking that with me knowledge and experience I could evaluate technologies (ostensibly items that aren’t branded and are sold in online states). This is thus a public service to help protect scammers. I call this service: “The workbench critic”. I will start with these 3-in-1 robotic cleaners.

So along this theme I came across this post and thought it very humourous:

General Purpose Technologies (GPT)

I think that we don’t always realise the impact that General Purpose Technologies (GPT) have had in our lives.

My definition of GPT is when things become so widespread that we see their applications all around us then they are General Purpose Technologies. In addition, my other criteria is when the economies of scale have brought their prices down to such an extent that these technologies become ubiquitous.

The following picture describes four such GPTs, can you guess what that are?

Four GPTs that are ubiquitous..

So these are: solar panels, lithium batteries, passive infrared sensors and light emitting diode (LED) lights.

Their combined use, in this particular application, means that this could be installed by anybody as it is completely safe – a low voltage system. Thus no expensive electrician required to do the installation, no 230V(EU/AUS)/120V(US) cabling and no certificate of compliance (CoC) from that same expensive electrician. The older halogen mains connected system would cost hundreds of dollars to buy all the components and get the licensed electrician to do the installation and then certify it as safe! The system shown here would cost less than $50 from a local hardware store and you could install it in less than 10 minutes without running foul of the electrical codes. The bonus of course is that it will still work during a power failure owing to the battery which is charged by the solar photo-voltaic panel so completely sustainable and renewable…

I love LEDs because their power consumption is very low and they are so safe, most of the individual units run on anything from 1.5V to 5V. We all love light and color which LEDs are exceptionally good at producing.

I was astonished how cheap these have become, these tealights would replace the dangerous open flame, candle-based units and last for many years. They also create a lovely ambience no matter what the occasion, even the occasional power failure (outage). These cost me less than 50 cents each within this 8 pack and even included the CR2032 batteries, viola! Date-night at home is going to be soo romantic due to this GPT :,-) Thanks to the engineer whom invented LEDs…

LED tealight “candle”set, all 8 for $3.90, a truly ubiquitous technology.

Thanks to Messrs Round (1907), Losev (1927), Biard (1961) and Holonyak (1962) and those that secured to increase their lumens output whilst driving their costs down. Thanks to engineers in companies like Toshiba etc we get amazing, commercially available LEDs, that have an efficiency of up to 223 lumens/watt.

The control of LEDs has also advanced and by mixing the intensity of red, green and blue, any color can be obtained from these three colour LED devices. Check out this rather inexpensive “Disco ball” which listens to the music and then responds with a fantastic display of color light.

Awesome “Disco Ball” using controlled LEDs

If you like my efforts, either buy one of the affiliate product kits or Buy me a coffee, it keeps me going!


Technology in recycling

Automated glass recycling acceptance machine
Automated cartons, cans and plastic bottle acceptance machine

Machines have made the world a better place. It is actually the engineers who develop these machines that are responsible for such improvements. Take the machines that we have in Australia as an example, these eliminate the need to sort bottles from cans, from plastics etc. The device scans each device that is entered and either accepts it for the recycling credit or rejects it! This makes good sense for the company recycling these items and those whom can conveniently drive to one of these machines and quickly get some cash back. Here you could 10 cents per plastic bottle. This is sustainability as it should be.

The ubiquitous Raspberry Pi (RPI), as a Network Attached Storage (NAS) device

A Plex Server home screen. Running on a Raspberry Pi (RPI)
The Network Attached Storage (NAS) using a Raspberry Pi

I followed the instructions below here, in order to use the RPI as a NAS with a RAID-1 array with two mirroring 2.0 TB Harddisk drives (the abbreviation for these is: HDDs, they can be seen in the photo). Samba is a service which makes the NAS accessible to Windows computers on the same sub net mask. The IP address and RPI credentials are used to access the NAS from a Windows computer. Also install CX File Explorer on your phone and then the NAS is accessible on you Android smartphone, a very cool feature.


I then simply used that same RPI which acts as the NAS, to also run the Plex server which is accessible behind the NAT by typing the IP address and port number which defaults to 32400. The Plex server is accessible with any webbrowser by any device on the same subnet as the Plex server. You can also set-up Plex server to port forward and thus serve you anywhere in the world using your login credentials. I have a double NAT, which means two routers between the RPI and the Internet Service Provider (ISP), so that is a tricky proposition to get external access for me. It can be done but one has to bridge the first router through to the second one, which I don’t want to do.

In the above photo you will see a powered hub and a RPI. The RPI gets its power from the battery bank and I will make a connection for the powered USB hub also to take its power therefrom so that it acts as a UPS, in the future.

Plex server instructions are summarised below:

Plex Install: https://pimylifeup.com/raspberry-pi-plex-server/

Set a Static IP for the RPI: https://thepihut.com/blogs/raspberry-pi-tutorials/how-to-give-your-raspberry-pi-a-static-ip-address-update

Install a Torrent Web App called Deluge: https://pimylifeup.com/raspberry-pi-deluge/

You also need to type in the following command:

sudo chmod -r 755 “your USB HARD DRIVE Path ie: /sda/pi”

This is required or the
Plex server won’t be able to read you usb drive.

If you don’t have a UPS and have a power failure and the RPI cannot see the RAID-1 array follow these instructions:


One of my drives failed and in the process of setting up a new one that I bought, which was smaller than the functioning 2.0TB HDD, I realized this cannot be done unless the sdb drive which only had one massive partition called sdb1 needs to subdivided with one partition exactly the same as the new 1.0TB HDD that I bought.

This is problematical as all the data on the Raid-1 array has to be copied into another drive, the sdb drive partioned and reformatted. The easiest way for me was simply to use the Diskmgt.msc function from Windows. The raid-1 array has to be stopped using the mdadm utility. Don’t reboot the RPI as this will cause a major lockout and disk fault. I did exactly that and then had to use the new rpi imager to reimage the RPI’s SD card and rerun through all these steps again. Oh mercy, that was a painful lesson.

Hello world!

The first words you wrote when learning a new programming tool, be it Arduino C, Micro-Python, VB6, C#, Python 3 or coding frameworks for any micro-contollers.

This is the first thing anyone writes when they are learning a new programming language and it is very gratifying when you try something for the first time and are able to write these simple two words. I can do that on many LCDs connected to micro-controllers or connected to better and more modern OLED displays driven by either a: Raspberry Pi, ESP32 or many of the Arduino boards. Some of the projects described on this blog started out with these simple words and have advanced to more information over time. In addition, I thinks its always great to greet your audience and so I say “Hello World” to you and hope you enjoy what I share in my personal blog. It somehow doesn’t seem right to me, to do something and yet not share it with those interested therein, across the world!!

Dolphin robotic cleaner which needs a “robotic finger” to operate

2 February 2020

I started with a much simpler robotic finger, basically to save me the pain of opening my pool pump box, every single day and then pushing the cleaner button OFF and then ON again. You can however get as sophisticated as you want with this exciting technology…

I rent a house which has an absolutely brilliant robotic cleaner called a ‘Dolphin’. It works well except you have to switch it OFF, wait 20 seconds and then switch it ON again for it to operate.

Apparently the next model up has a bluetooth interface for many hundreds of dollars more. If I want that option, after the fact, I would have to replace the whole cleaner…not great news!!

I thus set-about making a “robotic finger” to mimic this action every day, at a set time.

I use the famous Raspberry Pi 3. The first version of the ‘Robotic finger’s was, ummm… unreliable mechanically, I thus redesigned it. It also has a camera which shows me that the pump is running and the LCD display of the Davis pH meter. The first version is shown below:

Output from pool cleaners' web interface on Jekyll
The RPI 3 takes a photo everyday of the Davis pH meter and the indication of the pump master controller and publishes this photo to a Jekyll website

The ‘Robotic finger’ work-bench tested as follows:

“Automation” is what robots do best, things that are either too complex or to mundane for humans. I love this simple robot which takes blood pressure, SPO2, pulse rate (PR) and temperature from your finger and displays these parameters on an OLED screen!

Pulse, blood-pressure, SPO2 and temperature, “robot”
It comes in different colours for those whom think the black unit is too bland!

Power Bill Shock!

29 October 2019 (first created)

I am sure many of you have opened your monthly electricity bill only to feel a little bit of panic rising as your mind tries to comprehend the number before you. In my case it was the eye-watering $601.3, which was laid before me.

If you are anything like me, your mind raced to figure out what happened, right!?…Did we perhaps leave something on for a while, like a heater, the oven or a few split-system air conditioners? The heating appliances are typically the biggest energy consumers and air conditioners (in aggregate, if you have more than one split-system) can also result in some hefty numbers, especially if these are used days on end.

On my September bill the energy consumption was nearly double what it was as compared to the two coldest months in our city which are June and July. The green box, that I have marked up on my bill, shows those two presumably high consumption months and the red box shows the actual high consumption months.

These values in my bill are daily averages and gave me the insight that we ran a daily average consumption of a whopping 85.04kWh for September, …ouch!!. If you take the average daily cost and divide it by the average daily consumption, the numbers in the purple box, you may observe what the energy company charges me, per kWh of electrical energy. In this case this calculates to a rate of about 25.3c per unit for September. Not cheap by any stretch of the imagination and one of the main reasons that Australia has some of the highest roof-top PV penetration levels worldwide.

As I rent the house I live in, solar Rooftop PV isn’t an option for me. The house has solar pool heating whereby water is pumped to black heat receivers on the roof of the house.

The greater sense of dread comes from a feeling of: “Is this is our new bill going forward”? The first thing to do is check the meter reading (on my energy meter I have to read each digit from its corresponding dial for the various unit denominations: 10,000s, 1000s, 100s, 10 and 1 units, see the meter dials on the meter in the photograph below) and then confirm that the energy retailer has the correct numbers.

Then check the rate and see that this hasn’t changed from the previous months by recalculating the purple number from the previous month’s bills. This way you know that the rate hasn’t changed which may be responsible for this bill shock.

I my case, by analysing the bill I discovered that the problem was actually due to the readings being higher than the estimate that the energy company used. They seem to take the average over the last three months if they don’t have a meter reading.

When our consumption rose in winter, the 4 month accumulated correction of an additional 50kWh per month was not included in their estimate and when my wife phoned through the actual September meter reading, they made the correction. This added 200kWh to that month’s bill.

At least I knew that the bill wasn’t going to remain double but that it would still be higher than I anticipated. The important thing was to also phone through the next bill or else that would affect the retailers’ estimate and they would be holding my hard-earned coin.

This event did get me thinking that I need to have a bit more control of what is going on with my energy (electrical) bill.

I decided that I need to keep an eye on the pattern (or ‘load profile’ as it is more formally known as) in order to understand how, when, what is using power in my home.

This makes economic sense but as power generation from coal generates, just under 1kg of CO2, it is also good for the environment for me to do this.

You can use these handy little plug-in meters (as below) and make up and inventory of the average of each appliance. This helps you to keep stock of the usage.

I however decided that I want more information and a trend line which I can view anywhere and possibly also analyse using tools like those available from Thingspeak/Mathworks:


I also wanted to separate my house from my pool pump as I am able to set that timer and maybe optimise the energy that the pump uses within the context of the water quality. I thus searched for an energy meter that I could build and found a few. (See my blog post on how I monitor water quality:


I opted for one based on a Atmel/MicroChip ATM90E32S chip on a printed circuit board (PCB) from a company called CircuitSetup.us and which could communicate using the ubiquitous Wifi chip, the Espressif ESP32.

I also wanted two clamp-on current transformers (CT), one for the house supply and one for the pool supply, which this board allowed for.

The meter would need to derive its voltage reference and power from a plug-back power supply transforming the 230V supply down to 9V ac.

The clamp-on CTs simply clamp around the conductors on the back of the distribution board.

(Note: It is advised to get an electrician to connect these and put a plug socket into the board for you. I was lucky as my board already had a plug socket for electric lawnmowers).

The component elements that I used are shown below, and I put them all in a nice water-proof enclosure with leads for the plug-back and the CTS external to the enclosure.

The Wifi radio cannot transmit its signal through the steel box so I had to mount this box below the distribution board, out of the sun.

As you will read further on in this post, I found the signal strength with this external mounting of the power meter, inadequate for the reliable Wifi data transfers to the cloud service.

I also got a free cloud account from www.thingspeak.com and set up the Wifi chip to send data to the cloud so that I can look at the load-profiles.

Notice the two times that the kettle was put on to make coffee. By taking a few minutes in the morning and evening to look at these load profiles I can see the overall power trend and can compare this to how the pool filter pump affects the overall numbers (which is currently my single largest power consumer, since it is early summer and there is no need for indoor space heating or space cooling).

If I turn an air-conditioner on I can see the step increase in power in the next 5 minute average value and then know the impact of when I turn things on and off. I now have a very clear picture of what is happening at my house and hopefully should avoid any further bill shocks.

If you want one of these units let me know by dropping me an email at the email on the Contacts page.

Now I can watch my consumption and turns things ON or OFF to see their impact on the profile.

Key lessons learnt

  1. HTTP posts to the Thingspeak IoT platform are not as reliable as using the MQTT protocol to send data from the energy meter. The latter also uses less power.
  2. The use of a microprocessor combined Wifi device should make use of an external antenna which should be mounted through the power distribution box using a rubber grommet. This improves the signal quality of the communication between the home router and the energy meter. The device reports an RSSI of between -50 and -55dB which may be considered as a “good” signal.
  3. I have been able to reduce my energy bill by $100 a month by learning what the filtration and solar heating (water pumped to the roof of the house) requirements of my pool are without over filtering or heating the water!
External antenna improves the reliability of the connection with the home router
“Good” signal strength with the homes’ Wifi router

It’s is always good to see what is out in the market. I came across this system from Smappee which looks good but will cost about double what my CircuitSetup system costs. It does have one great feature which is the ability to discern the different home appliances from one measurement.

Water Quality, for pools and ponds

29 October 2019

We bought 9 Comet (a type of goldfish) and put them in a water plant filled oasis, at least that is what we thought until 6 of them didn’t survive three weeks.

To make matters worse the three remaining fish developed a disease called Ich.

A bit of research and I knew that I need to not only have plants to remove nasties from the water but that I also need to keep the dissolved oxygen high (using a pump and a bit of a waterfall), pH within a tight band and watch the temperature of the water to prevent these events from recurring again.

I built a lovely little Wifi-enabled pH and Temperature sensor and was sending the data to a website.

I then decided that it needs a battery pack and so modified it to accept such a pack and charging from a standard USB lead. I now also use it to check my pool water. I also added oxidation and reduction potential, also called “ORP” as a bit of research tells me this is a good indication of water quality!

The ESP32 integrated micro-processor and Wifi are inside an old underwater camera case. The three key values are shown on the display.
A BNC-type connector serves to connect both the blue pH and the black ORP sensors which are stored in their buffer solution caps strapped to the box (the internal battery is charged using the USB socket shown)

I am a huge fan of Thingspeak and the MQTT API for sending data to their cloud IoT ecosystem. For those so inclined, it allows for some rich data analysis and visualisations as Mathworks are the holding company thereof. Mathworks of MATLAB simulation fame. I don’t use their coding framework, as it is proprietary and prefer Python for coding data science scripts. Open source is better in my opinion as the help from community members is far greater than closed communities like those who can afford to buy and then use MATLAB.


Energy Management, but how?

First published: 11 June 2018 then updated 27 June 2020

    Most countries have energy labeling, but so what!?

    It took me a bill shock event to get me to really think about what to do. Of course managing your energy is good for the pocket but it is also good for the environment. You might ask how can anybody with a Ph.D, in this very field, get caught out like this? The answers is simply based on a few considerations:

    🚦When you do something for a living you don’t necessarily want to have much to do with that field in your spare time, not so?

    🚦When the bills are all within  tens-of-dollars of each other, each month, you tend to “take your eyes off of the ball”, as it were 🤓. I guess I have so many things competing for my energy and attention that I generally do not fix anything until it’s broke. Unfortunately, not monitoring you energy bill already qualifies as “being broke” 🤓

    🚦The “bill-shock” is something that you get days or weeks after something within your house changes, this with respect to you energy consumption. It is what I call an “after the fact” event, this the criticality of having a phone app that warns you when your bill goes over some preset threshold in kWh/day. I now have this but it took this energy cost-spike to start “practising what I preach” 🤓

    I have a Ph.D in strategic management around energy management, so have sacrificed significant free time in the study, research and development of strategic frameworks to help all people save money, become more sustainable by saving on utilities bills.

    Watch my video to see one methodology that may be used:

    PowerWin entering energy uses into a spreadsheet used by the model
    PowerWin Logo

    The Bill shock! post describes how you can monitor your bill and calculate your daily energy consumption in kWh.

    At a very fundamental level just knowing that each kWh costs a certain number of cents and being aware of how many cents you are using per day, is a very good start. In Australia, in Victoria, smart meters have been mandated for a while so to get that daily energy consumption from your retailer is really easy. In NSW, where I live, it is only mandated for new builds.

    As explained in my Bill Shock! post, I rent the property that I live at so I couldn’t make a permanent installation. I did get owner permission to make a little hole in the distribution panel for the antenna of my smart meter, so that it could reach my Wifi router.

    I monitor the following trend line, especially when running my solar heating and filtration system for the pool (wattsC(W)) or the reverse cycle air-conditioning for heating in winter. The total house load profile including the pool system is labelled wattsA(W), this on the y-axis of that chart. This keeps me, well enough, informed as to my costs on a real-time basis. In my case every kWh represents a 25c ‘assualt’ on my wallet.


    “Some have studied their fields over countless years, thus you can trust them more than those trying to make a quick sale…”