A Single Light to Monitor Them All in Real Time

The context

This week-end’s project was focused around building a simple indicator on my desk that alerts me of any problem at home in real time. That way, I don’t need to regularly check things around. Well, this may sound overkill for many people. But over the years, I’ve written a program to monitor many things around me without the need to perform a regular check myself. The only thing I was missing was some real-time monitor that would alert me whenever something urgently needed my attention.

Computers. I am a computer engineer, and as such I do have a few electronic equipment around. I also monitor the temperature, humidity in an out of the apartment and also water leaks with sensors, as I have some sensitive musical instruments in my home. In the past 2 months, the temperatures here have gone up to 37 degrees Celsius several times. These measurements have helped us, without air conditioning (which makes things worse on the long term), mitigate the heat. We could close everything when outside was hotter than inside, and open in the evening when the temperatures outside were coming close to the temperature inside.

Here are the temperatures my system measured for the last 5 days:

Where I came from

I already had a raspberry pi set up with a tiny monitor showing all the indicators and a big green light (or orange or red) showing the overall status. Something like this:

But this screen consumes 2.5 Watt when it is on, and only 0.15 Watt when it is off. This is a substantial difference, not even mentioning how much wear it causes the screen to be constantly on, just to show a green light!

The solution

A simple solution: use simple LEDs (which consume virtually nothing) controlled by the raspberry. So I built a first circuit to test the whole thing out:

Of course, that also works with the screen off, that’s the goal after all!

A printed circuit

I had to arrange things together on a smaller plate:

… and solder the whole thing together (yes I butchered the soldering, sorry):

That was a mess…

Buddha (you can see his legs on top of the picture) had a hard time coping with the mess, but he played his role perfectly and went into a deep meditation:

And of course I then had to use this very useful piece of equipment for the cables:

Trying it out

The first testing worked out as expected.

I just needed to print a little box for it with the 3D printer:

Final words…

Using a single green LED was not an option. If it was constantly on and green, it could simply mean that the program crashed… which is not good. I could make the LED blink… but any blinking inevitable catches the eye and is bothering. But two green lights alternating doesn’t catch the eye, and ensures that the program is alive.

On the other hand, the error state and the warning state with an orange light are blinking to make sure that my eye will see it:

And now I have an indicator on my desk telling me at all times that everything is ok. Or not.

The managing software is now on my gitlab: https://gitlab.com/jytou/monitoring-and-sensors/

Planned Obsolescence 0 – 3D Printer 3

Here is another short blog post showing the use of 3D printing against planned obsolescence… or simply the inevitable wear of objects, even when they are well designed. There was a part 1 and part 2 before this one.

The problem

In this particular case, I had a perfectly functional object… except for one little part:

As you can notice, the plastic piece that is supposed to hold the paper roll has broken. And it is not a simple fix with some glue:

Designing a solution

Fortunately, thanks to 3D printing, we can now print the same piece at home. Some 3D scanners out there can quickly scan the piece to print an exact copy. However, a broken part generally signals a weakness in the design. This is actually confirmed by the other, symmetrical, piece which started cracking in the exact some area. So printing the same piece would lead to the same problem later. Thus I redesigned it, adding some reinforcements in the area where it broke.. This way, I will reprint the piece with a stronger structure in the places where there is most tension:

Implementing the solution

And now we just need to print it:

The result looks good and quite similar to the original except it’s stronger in the weaker parts:

The main difficulty of this piece was the part that plugs into a rail on the main dispenser. The rail had to be precise enough to allow moving without being too loose.

And it is finally fixed!

Now I am waiting for the left arm to break – it will be a piece of cake to replace it.

Conclusion

Think of all the metal and plastic that could be saved if we repaired our objects instead of systematically buying new ones!

Planned Obsolescence, 0 – 3D Printer, 2

This is a follow-up to my older post Planned Obsolescence, 0 – 3D Printer, 1.

Have you ever had a problem with you vacuum cleaner where the electric cord just won’t stay out and will annoyingly get back inside the machine slowly? Like this:

Well, that happened to me. You can of course open it and try to figure out which piece is having a problem. But there’s a good chance that it won’t fix it for good and the problem will come back – that’s the whole point of programmed obsolescence.

So I designed a very simple clip to hold the wire in place, using the spring of a normal clothes peg – which by the way turned out to be very impractical as a temporary fix.

Here is the result:

 

Plain and simple, and downloadable on my thingiverse page, as usual.

So, here we go, Planned Obsolescence 0 – 3D Printing 2. 🙂

Broken Stuff 0 – 3D Printing 1

Recently, I got a package with broken stuff in it. It was actually some shelves with doors, and the broken part was that plastic part that contains magnets which hold the doors closed. Here is a picture of what I received:What generally happens in this kind of circumstance is that people will complain and return the package, then get another brand new article. That’s a lot of wasted transport and energy for such a little missing piece.

So I decided to 3D print the part. In the process, I decided to make it more ergonomic. Those white plastic parts are generally a little sharp and can even scratch your hand if you’re not careful. So I designed a round one. I also had some round magnets around and I decided to use those rather than the stock ones which are rectangular.

As the shelves were made of wood, I also printed that part with wood PLA. Here is the resulting piece with the original near it:

Then I glued the magnets in place:

And here is the final result:

Isn’t that much cooler than the original? I love 3D printing!

Planned Obsolescence, 0 – 3D Printer, 1

It is not the first time that I fix something with 3D printing. But this one was an interesting one!

The problem

A few years ago, I bought two stands for my microphones. Okay, they were inexpensive, and maybe it was a bad long-term choice. Maybe I should have opted for more expensive ones. But I have noticed that higher prices don’t always mean better quality. These days, they often mean higher reseller margins.

Anyway, both stands were poorly designed. Even though they did last several years, they finally broke recently, roughly at the same time. Unsurprisingly, the faulty piece is a part made of plastic. It sustains high pressure on a very small surface. And after a while, it just gave in. I believe that, without me noticing, cracks developed over time, until they became big enough to break the piece completely:

As you can see, it is pretty bad. Of course, I couldn’t find spare pieces, especially as these are already “old” (anything beyond a year is “old” nowadays). And without this piece, the stands are totally unusable.

Reflexes…

The first reflex was: it’s cheap stuff, I can buy new stands! Why bother for 20 euros?

But apart from this broken piece, those stands are in perfect condition and they could serve their purpose for many more years. Why pay? Why extract more metals from the Earth, build more plastic pieces mostly from petroleum, more rubber from trees or worse from petroleom again, use energy to forge, heat, assemble, then use again more energy to ship those new stands to me or go and fetch them from a local store – where they would have been shipped from somewhere anyway? And dispose from transport boxes that kill trees? As well of course as disposing from the broken stands. And as a result buy new stands in a few years when those new ones will break?

I didn’t actually want any of that, especially as I have the “Planned Obsolescence Killer” at home : a 3D printer!

Compared to all the waste of buying brand new stands, printing a piece is quite environment-friendly: it does use some electricity (not much), and I mainly print using PLA, which is basically made of… corn. This material does have its pros and cons, but it is certainly better than petroleum-based plastic.

Designing a solution

I spent some time designing a solution. This piece allows the axis to be rotated to the desired angle, and it is a functionality that is really needed for this kind of object! So even though there were many alternative ways of fixing that stand, I wanted to stick with the original design as much as possible.

On the other hand, printing this kind of piece with PLA was going to get me in the exact same trouble in a few years: the plastic would certainly not resist the pressure. I could also print with nylon, but I try to avoid it as much as possible due to environmental concerns. Besides, given the pressure on that piece, I wouldn’t be so sure that even nylon would resist for a long time.

I first thought of adding washers to maximize the surface in contact, but I finally came up with using nuts with a ring base.

3D modelling and printing

Here is one part of the final model:

I heated the printer and printed the pieces:

Results

That piece has two other pieces which hold the nuts in place and stop them from turning, even if the pressure actually isn’t a rotating one but a pulling one.

Mounting the nuts in place and putting one of the pieces in its socket:

The socket for the second piece is clearly visible. The final mounted piece:

And now it was just a matter of putting it instead of the old piece:

Et voilà ! Both stands are fixed with just a few grams of PLA. I think they will last some more years. In fact, I believe this kind of thing should last at least for a lifetime. But then, how would we sustain “economic growth” to pay for growing banking interests?