Help with building your Speeduino, installing it, getting it to run etc.
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By PSIG
#57216
dener0987 wrote: Sun May 29, 2022 1:50 pmAs for the Trigger edge configuration for inverter conditioners (Max, Lm1815) shouldn't the edge be Falling?
No, as the output signal is being inverted, the signal is falling but the output is rising. Set for Rising Edge to read the falling sensor signal at the trailing edge of the tooth.

With standard sensor polarity (voltage falling on the trailing edge of the tooth), an inverted signal would actually be reading the rising voltage (falling inverted = rising) on the tooth leading edge. Worse, it will read the rising voltage in the middle of a missing tooth, as shown by the tooth logs below, confusing the processor.

The first image is correct sensor polarity, inverting conditioner, detecting Rising Edge. :D The second and third images are reversed polarity Rising, and correct polarity but Falling edge. :( Tooth logs are valuable to see what the processor "sees". One clean tooth gap works. Note: The first image may be incorrectly found with reversed polarity sensor, inverted, and Falling setting; but that configuration is prone to timing drift due to a factor called hysteresis. :roll: Note 2: While Hall sensors are often claimed to be immune, this effect can also occur with those sensors. You can see the same effect in your first-post 'scope image, the conditioner square-wave signal with the odd "wide" tooth at the gap. ;)

The height of each bar represents the time from one tooth to the next. A missing tooth (gap) then shows as a long time bar to the next. Two long time bars is reading the wrong edge, including one that doesn't exist in the gap. The first image, with correct sensor polarity, is the goal:
60-2_negF_negR_posF.jpg
60-2_negF_negR_posF.jpg (70.06 KiB) Viewed 1248 times
By Rob
#70463
I was thinking about the power supply for my own speeduino and whilst looking for LM7805 options on the internet I came across some buck converters with a similar form factor. The increased efficiency aka reduced residual heat offered by a buck converter is appealing but with such a small form factor there is never going to be the best of filtering on the output.

So I did a bit of searching as to suitability and came across this post. It seems that noise is an issue as far as the VR sensor is concerned but would I be correct in assuming the rest of the “system” can tolerate the noise from the Buck converter? I ask because I’m looking to use a MAX9926 VR conditioner which has provision on the module for mounting a LM78L05 which should provide cleaner power for the VR sensor.
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By PSIG
#70472
'Better' quality buck converters (e.g., Murata) have been used directly by some here without problems. I have used bucks at 8V out to an LM, so both run cool, but wanted the LM to help filter any buck noise. Whether using both was necessary or not I don't know, but it worked fine. From this, I would take a guess that a buck (only) should be OK, if you pay close attention to the in/out filtering on the datasheets. If you try something (LMR51430 on 7805 footprint? :P), let us know the results!
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By PSIG
#70500
Speeduino supplies robust 5V power on module pin5 to the conditioner in most designs. Other board types that are un-powered or 12V powered to the module can make use of that conditioner's optional 5V regulator. There are other purposes for using a second 5V regulator circuit, so let us know why you would add a second regulator and how you expect it to improve function, so we can be 'on the same page'.

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