StuntSabers 3.0 is already here!

First generation, however brilliant, was somewhat lacking in functionality. Well, I still believe it was the top shelf still, but it pales in comparison to gen2 which continued to build on solid foundations and expanded all the features and also added a couple new ones, like individual flash effects for all sounds, smoothswings, better implementation of blade effects such as breathing and flickering as well as many other bigger and smaller improvements. It was, however, mainly a software change - both inside the saber controller and the app that allowed you to comfortably connect and talk to it.

This time however changes are mostly in hardware, though of course there are also changes in the saber's fiirmware and the app as well, which was completely redesigned. Let's get to the changes in the controller which I internally named LightHeart 2.0

Illumination 2.0

Not only 2.0, but also twice the power. Technically speaking I have been using a 24W LED for quite some time now, because even if you power it with only half of that, it still has some advantages, mainly it remained fully bright a bit longer, before the battery's voltage dropped enough to also slowy start diminishing the LED brightness. However it would be a blasphemy to have such power available and not use it.

Easier said than done. The way LEDs are powered is quite interesint in itself, but not to bore you I will only say that it comes with a lot of difficulties, for example getting rid of all the heat that it generates. And the heat comes not only frome the LED itself which converts most of the pwoer it gets to it, but also the power supply cicruit board which needs to handle quite gigantic (especially for such a small space as a lightsaber hilt!) current. So now instead of a single controller, there are actually two. One is the brain of the operation and is responsible for all the features working, while the second one has only one purpose - to power the monster RGBW CREE LED that is inside the saber.

Anyway, I succeeded and long term test suggest that the saber is capable of dissipating the heat just enough even when it is not moving, which is the worst case scenario. Does it mean that the saber will be twice as bright now? Unfortunately not since brightness does not scale linearly - which has its advantages, like Earth not becomeing a ball of gasses from the incredibly bright Sun), but also disadvantages - even though the power is doubled, the actual difference in brighntess is smaller. I wouldn't go to such lengths to do it if I didn't think it is worth it, but I don't want to spread false claims. So brightness is visibly better, but not to the point you will need sunglasses. I am also quite sure that I have reached the limit of what is practically possible for baselit sabers. Any more power and it would be hugely difficult to provide it and dissipate the resulting heat, while the brightness change would feel smaller and smaller.

Sound... also 2.0

Here we have double the profits. Thanks to increasing the resolution of sound samples by a factor of sixteen I managed to eliminate the quantisation noise. Under this menacing there there is nothing particularly complicated - having only 8 bits to present a sample we have values of 0-255 available. Thiis is unfortunately not enough to faithfully replicate a sound and a small bit of noise is also generated which cannot be temoved from the samples (because it is not in the samples themselves), but it can be alleviated with other ways. In second generation lightsabers there are some acoustic panels inside that mostly filter this unwanted effect. If you put the end of the saber to your ear you will hear it, but in regular use it should not be noticable.

I, however, was fairly annoyed by it, as it also had another disadvantage - when raising the volume of the souds, the noise would also be amplified. Thanks to increasing the resolution to 12 bits we now have numbers from 0-4095 which is plenty to completely eliminate the quantisation issue. It is actually enough to play music of quite nice quality, which was one of my favourite things to do when I was testing the new system. Larger samples also require more processing power to... process the ad take twice as much space, but both those issues I managed to resolve, though it did take a couple of days of troubleshooting.

Thanks to increasing the sound quality I could now get to work on the volume by increasing power available to the audio amplifier in the saber. I managed to get 6 decibels, which is a significant loudness change. Sound, just like light, does not scale linearly. To get the roughly 25% increase in volume the power delivered to the speaker had to be qadrupled.

Oh, and the numbers 77db and 83db are meaningless alone - those were just the conditions where I compared both generations using the same parameters. The important part is the difference, since the saber can go way higher than either 77 or 83dB in some cases.

Memory times two

So as not to say 2.0 again, though admittedly there is just about twice as much memory now. Technically speaking four times (I did not make a mistake on the graphic above), but since samples take twice as much now as well, the resulting gain is also twofold. This may come in handy in the future when new soundfonts are available, since the latest one was already at the limit of the saber's mameroy.

Hunting milliamperes

Sometimes you asked me whether it is normal when the saber, after a prolonged period of not being use was dischargin itself. It was indeed happening, and while it didn't have any negative effects on either the saber or the battery, it was a slight point of pain for me. It took just a few weeks for the battery to go from full charge to zero, even though the sabers was not used. Small invonvenience, but inconvenience nonetheless. After all you needed to remember to charge the saber to use it if you didn't do that for weeks.

I have performed some measurements and it turned out that the saber use from 6 up to even 10 milliamperes when asleep. Doesn't look like much - with a battery capacity of 3400maH it means that it can supply 3400milliammpers for an hout before it is discharges. For 10 milliamperes we end up with about 340 hours, which is a lot, but still only weeks. Since I was already deep down in the deepest systems of the saber, the hunt started.

The first and most important culprit was the IMU - Inertial Measurement Unit - which is an accelerometer, gyroscope and magnetometer all in one, responsible for detecting saber motion and vibrations. Fun fact - it is the most expensive single element on the whole PCB, more expensive than even the processor. The way it works is quite interesting, but not to dive too deep it is actually a mechanical device which constantly uses somewhat huge amount of current - 3 milliamperes - which is not insignificant when everything is powered by a battery. The solution was simple - the IMU had to be put to sleep along with the rest of the saber. I must confess that it was my lack of knowledge mostly at play here, since the absolute majority of integrated circuits consume miniscule amounts of power when not in use, amounts that are hard to even measure. Still, with an accelerometer and a gyroscope the story is different and it was consuming the precious miliampere-hours.

The second culprit was the processor itself, which even asleep was consuming just above a milliamper. Thanks to making sure to put some more systems to sleep and decreasing its clock speed when it was asleep, another step was made to make the battery last longer unused.

There were a couple more changes to the layout of the board itself, but overall thanks to all the changes now the saber consumes less than a single milliampere, which increases the discharge time from 340h to roughlt 3400h, which is a couple months. Small thing but it was important to me.

Gestures easier to use

A change in programming was a second attempt at cracking the gesture menu, which in short allowed you to change the settings of the saber without needing to connect it with a phone or PC. It worked quite fine, but the way to activate it which were a couple of specific gestures were problematic, since they sometimes activated randomly while performing rapid movements with the saber. Of course I tried to combat it by detecting such situations, but it is always better to prevent then try to fix.

In third generation the menu is no longer activated via gesture. Now,, after turning the saber on you have a specified time to press the button again and hold it. Default is one second, which might seem low, but is plenty time when you want to use it. It can be changed with the app - of course :) After this time the system can no longer be activated, so there is zero chance of accidental use. I think it is also just easier to use.

Accent swing

Dodatkiem programowym jest też accent swing, czyli uzupełnienie do smoothswinga. Jeśli nie chcecie zupełnie rezygnować z odtwarzania przygotowanych dźwięków, teraz można sobie ustawić próg, po przekroczeniu którego nawet w trybie smoothswing odegra się swing, która ja nazywam statycznym, czyli po prostu nagrany wcześniej dźwięk. Opcja wykorzystuje właśnie dźwięki, które odgrywane byłyby w trybie statycznym.

Another firmware update is accent swing, which is an addition to smoothswing. If you want to keep using the prerecorded sounds even when using smoothswing, you can now select a threshold which will activate them. The soundpool used is the same as regular static swing.

Did I turn the saber off?

There are no stupid questions, but this one might seem so. In this new generation it is actually quite relevant, since a system was added that will turn the saber off after a couple minutes of total inactivity. I wouldn't think of anything like that if not for the amount of power that the saber now has, which results in emitted heat. No movement at all is the worst case scenario and I have tested it to make sure it will be fine anyway, but why push it to the limits when it is not necessary. The system can be turnet off but it shouldn't ever be necessary. If you are not using the saber for a couple of minutes already anyway then there is no point in wasting the battery.

So, when does it come?

It comes now, and the be more specific all sabers from November 2024 onward will have the new system. I want to make sure that you never regret buying your saber, so it is customary for me to actually release the new version earlier than telling about it. It does mean that those orders will take more time but I think it is worth the wait :)

03.12.2024

2 months ago

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