Resources

Resources to simulator builders and tinkerers alike

Contents:

RC Filters...................................................................................................

Our Custom Printer Profiles.........................................................

RC Filters

What are RC filters and why are they useful?

RC filters (resistor-capacitor filters) are simple filters consisting of a resistor and a capacitor. When wired correctly they can significantly reduce the amount of noise in an analog signal. While there are two most common RC filter types, low pass and high pass filters, in this article we will talk about the low pass filter since it is more useful to our application. We will focus especially to RC filtering analog potentiometer values.


Low pass filters are used to filter out high frequency signals while letting lower frequencies through without effect. This way you can cut out "spikes" from your input and what remains should be a smoother signal. As a side effect you can start to lose data if you want to make sudden inputs that could be detected as noise even when truly not. That's why you need to carefully consider which values you want to assign to your filters resistor and capacitor.


When choosing the appropriate cutoff frequency

(frequency which gets attenuated by -3 dB or 70%)

you need to consider what kind of inputs are you

expecting to receive and above what frequency is

the signal going to be obvious noise. We have found

about 500 Hz to be a good cutout frequency for our

flight simulator applications. This way you can still

make radical movements on your flight controls

(sudden pitch movement ie.) but the noise above

that won't be picked up by the controller.


After choosing the appropriate cutoff frequency (be it 500 Hz in this example) you need to calculate the correct values for your RC components. For this you could use formulas and find your values that way but online tools such as this DigiKey RC Filter Calculator will make your life much easier. However it isn't just about selecting some random values to get the desired frequency. You have to make sure the resistance of your resistor isn't too low or high.

A too low of a resistance will load the input device (potentiometer ie.) while too high of a resistance will increase the impedance and cause more noise than filter noise. It's easy to experiment with different RC values and see what works the best for you but generally a resistance much higher than your analog devices resistance while not exceeding 1MΩ will do the job.


We sell products with built-in RC filters and generally pre-install the following resistor and capacitor to the signal:

- 100kΩ resistor

- 3nF capacitor.

This achieves approximately 530Hz cutoff frequency just like we wanted.


If you have more questions about RC filters or anything related you can find our contact information here.

Schematic shows how to wire a simple low pass RC filter to an input signal.

Our Custom Printer Profiles

Over the years we have been perfecting our slicer settings to achieve "quite perfect" prints especially when it comes to 3D printing text with multi-material systems. In this section we will go over our settings for BambuLab Studio Slicer and our P1S printer but the same settings can be adapted to any slicer and printer.


The Bambu Studio has grouped the setting to 5 categories; Quality, Strength, Speed, Support and Others. Before we can adjust any of these settings we need to establish which nozzle and build plate we are using. Our settings are meant for 0.2 nozzle and the smooth bed that BL offers. Although the settings should work for any filaments, it's important to point out that we primarily use PLA and that drying the filament and calibrating the K-factor is really important. You can find more about K-factor from BambuLabs resources online.


1. Quality:

This page is perhaps the most important because it adjusts the horizontal expansion and other important values that effect the out come of the text on your panel.

Layer height is one of the only settings that doesn't really have a meaningful effect on the text since it only changes the vertical movement. This setting should be selected according to the 3D contour of your print. For flat panel something like 0.14mm is perfectly okay and it won't take days to print (literally).

Line width is really crucial to getting nice bottom and surface finishes on the print. This also effects how the text will come out. If your letters come out squished and don't look sharp you might want to lower the line width even further. Don't go below the nozzle width or your prints will start breaking apart on their own.

The seam and precision settings have less effect on the over all result but we have found these settings to be fine for our purposes.

We don't use ironing because the panels are printed with the text facing down and the top side (actual bottom) won't be visible. It might be worth checking out in the future if we experiment with it more.

Wall generator settings have some really cool functions that many people are missing out. The Arachne generation can make small text way better than the Classic generation. It's certainly worth turning on! We are still looking for the perfect settings for the Arachne generation but these setting have been good for us so far. You can read more about Arachne wall generation from the slicers info panel but essentially it generates walls with variable extrusion width which is exactly what we need for small text.

Advanced settings also have some cool settings that result in better surface finishes for panels. Notably the "Only one wall on first layer" has a huge effect on how the text looks. This settings should be turned on.

2. Strength:

This page might not have much effect on the look of the panels but it's important to make sure you are printing the panels strong enough but also not wasting filament with way too dense infill.

Often infill setting can be further reduced to 10-15% but we like to keep it around 25% for durability. More important are the wall thicknesses. About 1mm walls are efficient for strong prints and make sure the infill doesn't show through the walls.

3. Speed:

Changing the default speeds have not been our priority because quality comes before speed for our panels. We will include our speeds here but DO NOT copy these unless you have a P1S or other printer that is capable of using the following speeds.

4. Support:

Supports are rarely needed if you are printing just flat text panels but there are cases where supports are mandatory. For those times you really want to dial the support interface settings perfect. We have had really good results with the following settings using regular supports.

One might want to also use the tree supports instead but we haven't tried them yet. For large flat surfaces regular support generation is better regardless. We also use independent layer height for support to speed up the process.

5. Others:

Lastly we have these misc settings which might or might not be any use for just you. One thing to note is the flush options when printing with multiple colors. You shouldn't be flushing to your infill because when you shine light through the panel you can see the different colors inside. If you don't need backlighting then you might want to enable flush to infill to save on filament.

Hopefully these settings will help you print amazing panels like we have been able to.

Here are some of our recent results. Note that sometimes we also apply a clear coat of spray paint to smooth out the surface even further.

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