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My first Benchy

Sunday, July 14th, 2024 at 03:58pm

Ever since I first heard about 3D printers I was intrigued, but not interested enough to delve into that low level of hardware tinkering. Over the years I have noticed that they have shifted from being a project in themselves, to being a tool to use for other projects. However it is only in the last six months or so that I have seriously considered getting one as a way to improve my home automation projects.

Every two weeks at work we have someone give a presentation on something that interests them, it does not have to be work related so there have been all sorts of talks. Earlier in the year I gave an update on my home automation, but last Friday the topic was how to get started with 3D printing.

That night I placed an order, the printer arrived on Thursday and within an hour I had my first Benchy:

Small 3d print of the Benchy benchmark

In that talk and other places (blog posts, youtube videos) there were essentially two brands to get started with: Creality or Bambu Lab

At first I was leaning towards a Creality Ender-3 as I liked the open source design and the flexibility that would give. However the large number of different models was a bit overwhelming and while I could tinker with the setup and software, I was leaning towards wanting the printer to be a tool…

This means that despite the closed source design and the default printing flow using a cloud service, I opted for their cheapest and smallest option which is the Bambu Lab A1 mini. The print bed might be small, but it should be big enough for anything I have planned (brackets to mount sensors, small cases for projects) and I did not get the AMS as I do not plan to print in multiple colours (and that almost doubled the price…).

In the end I paid $428 to get the printer and three spools of filament. Obviously this is a price I was happy with, now that the printer has arrived I appreciate how compact it is and how it fits down the end of my desk.

So far I have played around with printing a few widgets from designs available online:

Various 3D printed widgets

I have only encountered two issues while printing these, one maintenance and one design.

For the later prints I found that the print would fail to adhere to the plate and a blob of plastic would form around the print head as it continued to print further away from the print bed. I have only been using one side of the plate and I have not cleaned it. So the solution might be as simple as following the instructions to clean the plate using dish soap and a microfibre cloth. I should also keep an eye on the print at the beginning to make sure it starts ok.

The design issue is that when the prints complete the print head is raised up away from the print, but due to how the filament tube is mounted this also draws filament off the spool. Then once the next print starts the is excess slack in the filament and it has been slipping off the side, then later jamming. One of the suggested mods I have seen is to print a handle that also doubles as a spool relocation. With the spool up higher the filament tube is in a different location that does not move with the print head, so it would not cause this excess slack. I don’t know if I will do this, or if I will try to remember to check that the filament will come off the spool ok.

My next step is to start learning how to design objects to print, with my first project being brackets to mount microswitches to the track of my garage door opener. I have had the software side of that ready for a long long time, but I was stuck at attaching the hardware.

Over the last week I also designed and ordered my first custom PCB (more on that later), these two techniques open up a number of possibilities…

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Did I make a mistake?

Friday, June 21st, 2024 at 07:18pm

Today is the winter solstice and over the last few days it has been quite clear that winter has set in in Melbourne with headlines such as “Melbourne shivers through coldest winter day in four years…” so it seems appropriate I give some updates on how my solar, AC and heat pump hot water system are going.

A big question I asked myself was whether I made a mistake in getting my gas disconnected. Previously I would have the central heating on a schedule that I didn’t think about and my entire house would be warm at the times that I was awake. The AC units in my study (during the day while I am working and then in the evening) and bedroom (a bit in the morning for when I wake up and then a bit in the evening before I go to sleep) do a good job if I close the doors to those rooms, which means the other rooms (kitchen, bathroom, lounge) are cold.

It isn’t actually that bad, but it is noticeable when I move from room to room. Thanks to my monitoring I could also track that when I was in my study that the CO2 would climb to 1500ppm and at times I do feel a bit sluggish. My mitigation so far has been to get up every hour and go get a drink or go to the bathroom, this lets enough fresh air in to drop the CO2 down to around 600ppm from where it will start to climb again. The alternative is to leave the door open (like I used to do) but then the AC unit is trying to heat my entire house which is not efficient.

With the shorter and cloudier days there has been a noticeable drop in how much my solar panels are generating. At the peak of summer they would generate almost 30kWh over the day, but the best I have seen recently is 17kWh on a day that was sunny all day, but that is the difference between 13 hours of sun high in the sky versus about 8 hours of sun that is lower. Though even on a day that rained all the way through the panels managed to produce around 3kWh which was about a third of my consumption for that day.

I could also notice a pattern of the solar generation being best in the early afternoon, the day would start out cloudy and the clear up for a bit. To better take advantage of this I changed the schedule on my heat pump hot water from 10am to 1pm with the intent to run it both from solar that I am generating and also to be in a warmer part of the day so it should run a bit more efficiently. I don’t have a way to actually measure this, but it seems like the right thing to do. What I can also see is that where it would run for just over an hour when the ambient temperature was above 20°C, but now when the ambient temperature is below 10°C it is running for a bit over two hours.

All of this is just the detail, what really matters is the long term so it won’t be until the start of next year that I can sit down with the data and compare 2023 with gas heating and no solar against 2024 with solar and three heat pumps…

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From stream back to broadcast

Thursday, March 21st, 2024 at 07:55pm

This tangle of wires is my new morning alarm:

The parts in this picure are:

  • Cheap set of computer speakers (that run from 5V)
  • An unbranded Si4703 FM Tuner Breakout Board
  • D1 mini arduino board (runs from 5V and has built in wifi)
  • Relay (to control power to the speaker amplifier)
  • Momentary switch (to give it local commands)

It has been a bit more than five years since I switched to using a Chromecast speaker playing the internet stream for a radio station as my alarm clock. It has mostly been fine, except when not…

The first major issue was not that long after I set this up, the radio station I had chosen decided to change their main stream over to HLS which it turns out my speaker does not support. I tried to work out if there was a proxy I could use (or make) to covert HLS back to the older style, but then managed to locate an alternate stream for the same radio station.

An intermittent issue, but happening more in recent weeks, is that sometimes the stream doesn’t start, or the stream will start but then after a time will stop. I can see from the Home Assistant logs that it does start but then falls back to “buffering” and then off. I’m thinking that this is a network timeout or other issue.

I have also been looking out for a new speaker for the kitchen, but here it is not for streaming the radio, but for playing podcasts from my phone via bluetooth. The cheap speaker I have now doesn’t always connect to my phone and I want something mains powered so I don’t have to remember to turn it off to make the battery last as long as possible between recharges.

As I was struggling to find a non-portable bluetooth speaker for the kitchen I started thinking about a cheap mini hifi that had bluetooth. That thought evolved into what able using that for my alarm because I now have an IR blaster to control my AC unit, that could also send commands to a mini hifi.

Looking though parts I have picked up over the years I came across the Si4703 FM tuner board, what if I revisited that idea? It would better integrate into Home Assistant as it could give current status that an IR blaster cannot do. These thoughts felt familiar, so I looked back at my post from five years ago. Huh. These are all options I looked into back then…

Instead of spending money on a mini hifi I realised that already had the parts I needed. The FM tuner board and a spare set of computer speakers could be the alarm, then the current chromecast speaker could be moved to the kitchen and used directly with bluetooth. What really made this come together is this video from two months ago:


Old-School Radio: Integrating an FM Receiver into Home Assistant

It is looking like the example code from the video will do almost what I want. I might go through and strip out the serial control and OTA update functionality that I’m not going to use, but apart from tweaking some of the defaults and adding in control of a relay I think the software side might be sorted, including a panel within Home Assistant that I have updated with local station presets.

I have been using this for around two weeks now, it is working quite well so I should get around to tidying it up into a project box.

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Four years?

Saturday, March 16th, 2024 at 05:24pm

Yes, another year has gone by which means it is four years since I started working from home. It still doesn’t feel like it has been that long, but the calendar does not lie…

There are still some things that I don’t like about working from home, but all of them are vastly outweighed by not having a daily commute. Of course I could be doing more productive things with those two hours a day, but I prefer to take it easy.

That said, over the past six months I have started crossing things off my long todo list. Many of them have been tasks around the house that I have neglected, but others are investments in things like going all electric with solar panels, heat pump hot water and air conditioners for cooling and heating.

The house projects will continue, but after another lull last year I plan on making more of an effort in getting out with my camera…

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First full month with solar configured

Friday, March 8th, 2024 at 07:02pm

It has been a month since I last mentioned my solar panels and this time the significant thing is that I have received my electricity bill for the first full month since everything has been set up. No partial feed-in tariff and no admin charges.

It is pretty much as I expected with what I get paid for the solar balancing out what I am charged for pulling from the grid, leaving the daily charge:

I can’t compare the reported usage against what Enlighten reports because my Envoy gateway has been a bit broken (but now replaced). After the long power outage earlier in February it failed to report to the cloud, although the Home Assistant integration was able to pull data from it just fine. Even then Home Assistant data isn’t complete as the Envoy would at times drop off the network, but llowing for some missing data the usage values do line up.

So how does this compare against a time before I got the solar installed. That would be October 2023:

It is nice that my monthly bill is now a quarter of what it used to be, although I expect it to rise as we head into the colder months when there is less sun and I will be using electricity for heating. No more gas bill though :)

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