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Rotor Master

Old 08-20-2023, 09:07 PM
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Originally Posted by gigaplex
What stock rotors get that high? Highest I've heard of is ~1850, I've only seen mod rotors go higher.
I said stock rotors are heading that direction. Reread what I said, you said the same thing as I did more or less.
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Old 08-20-2023, 11:45 PM
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Originally Posted by Alexv2024
I said stock rotors are heading that direction. Reread what I said, you said the same thing as I did more or less.
In what way are they heading in that direction? They've been in the ~1850 upper limit ballpark for years. The rules limit their dimensions and material, which is a pretty big constraint to magnetic strength.
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Old 08-21-2023, 06:04 AM
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Originally Posted by gigaplex
In what way are they heading in that direction? They've been in the ~1850 upper limit ballpark for years. The rules limit their dimensions and material, which is a pretty big constraint to magnetic strength.
Not all the rotors were the max dimensions a year or so ago when a friend and I did some testing and motor tuning. And materials get refined all the time, so who knows when a stronger magnet will get relased.

My point is that things will eventually progress, and theres mod rotors that already go beyond 2000 strength so a tool that cant measure that is not great. Its nice to track even your mod rotors strength so that motor ever gets hot you can check the rotor strength and see if its hurt. But more importantly having a tool that can do say 2500 accurately now would be useful for years to come giving you a baseline now.

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Old 08-21-2023, 06:08 AM
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Personally I think a tool with an accurate range of 1000-2500 would be perfect for any 1/10 application right now and for years to come. I applaud trilerian for designing it and basically showing us how to build our own fairly easily. With some hopefully easy tweaks it could be much better. Like I said I want to build one but it'd be much more useful with just a little more range.
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Old 08-21-2023, 06:34 AM
  #20  
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Originally Posted by Alexv2024
Not all the rotors were the max dimensions a year or so ago when a friend and I did some testing and motor tuning. And materials get refined all the time, so who knows when a stronger magnet will get relased.

My point is that things will eventually progress, and theres mod rotors that already go beyond 2000 strength so a tool that cant measure that is not great. Its nice to track even your mod rotors strength so that motor ever gets hot you can check the rotor strength and see if its hurt. But more importantly having a tool that can do say 2500 accurately now would be useful for years to come giving you a baseline now.
The rotors that weren't the max dimension weren't the ones hitting 1850+. Neodymium hasn't had any advancements in a while, so we're not likely to see a sudden jump with a refinement of that process any time soon. Any new material that ends up being stronger won't be legal.

Mod rotors have already been covered as a reason to have a different version, but that's separate to this being useful for stock rotors.
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Old 08-21-2023, 07:24 AM
  #21  
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Originally Posted by Alexv2024
Personally I think a tool with an accurate range of 1000-2500 would be perfect for any 1/10 application right now and for years to come. I applaud trilerian for designing it and basically showing us how to build our own fairly easily. With some hopefully easy tweaks it could be much better. Like I said I want to build one but it'd be much more useful with just a little more range.
There are a couple of options available for measuring a higher strength rotor. First option is to move the sensors farther away from the rotor. But doing this you have to increase the multiplier you use for your measurement, this reduces resolution in the readings. ie, instead of the number increasing by 1-2, it would increase by 5+.

These units, mine included use a sensor that measures the change of the output of the hall effect sensor. This change is in millivolts. The sensors we use have a sensitivity of 1.3mv/gauss. They have a range of 0.55v-4.50v, with a quiescent output of appx 2.5v. So that is basically a 2000 mv range. 2000/1.3 = 1538 gauss. To get the best resolution, I have the rotor as close to the sensors as I can to achieve the common readings of spec motors.

Another option is to use a sensor with 0.5mv/gauss sensitivity. I do have some of these and have made a unit with them. They will be less accurate, but you can get readings of 4000 gauss using them.
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Old 08-21-2023, 08:55 AM
  #22  
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If you can find sensors with a digital output then you can get rid of the AD converter and probably also program the sensors with some filters if needed.
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Old 08-21-2023, 09:08 AM
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Originally Posted by Roelof
If you can find sensors with a digital output then you can get rid of the AD converter and probably also program the sensors with some filters if needed.
I found a sensor from Texas Instruments that outputs a PWM frequency. Could use that and create interrupts to measure the rising edges to figure out the gauss. Interesting. I will look into this!
Thanks.

Edit: Obviously that is a complete redesign of the entire project, so it may take me a bit to get to.

Edit 2: As to filtering the output of the sensors. I'm glad you brought this up. I was originally planning on putting a low pass filter on the sensor outputs as the datasheet calls that out for the standard design. But after looking at the outputs on my scope I didn't see any difference in the output vs transient noise. This could be a limitation of the scope, considering mine is relatively cheap as far as oscilloscopes go. Regardless in my next design I was going to add a low pass filter to each sensor as well as another decoupling capacitor to each input, but I do think it is just throwing components there that are not really needed.

Last edited by trilerian; 08-21-2023 at 10:33 AM.
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Old 08-21-2023, 09:49 AM
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Originally Posted by STLNLST
Hereís the Amazon link to the case pictyfor anyone that purchases/builds one.

https://www.amazon.com/dp/B07QRFX94D...p_mob_ap_share
Case fits beautifully, great find!
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Old 08-25-2023, 09:00 AM
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Finally life slowed down enough to play with the rotor checker. Another thing for guys to not have to worry about charging a pack to use during testing for this or your motor analyser is this lil power regulator thingy (canít remember the exact name) Hooks to your power supply and you can set the voltage so tests are repeatable and aren't skewed should lipo voltage drop. Especially when tuning motors. This was about $20 shipped off Amazon. Iíve had this for quite a while so I donít think I have the link saved. I while search and post it when I have more time later on.
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Old 08-25-2023, 09:20 AM
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Duplicate
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Old 08-25-2023, 09:27 AM
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So comparing this to my Fantom the numbers donít exactly match but what they both do consistently is give the same readings every time. The lower numbered rotor on my Fantom also showed to be the the lower rotor on this unit. I also like that the connecting plug was provided for me to wire up how I pleased.


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Old 08-25-2023, 09:41 AM
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Originally Posted by STLNLST
So comparing this to my Fantom the numbers don’t exactly match but what they both do consistently is give the same readings every time. The lower numbered rotor on my Fantom also showed to be the the lower rotor on this unit. I also like that the connecting plug was provided for me to wire up how I pleased.



Just curious, are you checking both plus and minus sides? I only see pics for the minus side. The plus side doesn't have a dash next to it.

I guess I probably should re write the code to make that more apparent. Add a + to the plus side readings.
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Old 08-25-2023, 09:44 AM
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There are a few more lucky people that have these on the way to them.
Also I have a big order from a distributer I will begin filling next week.
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Old 08-25-2023, 07:02 PM
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Originally Posted by trilerian
Just curious, are you checking both plus and minus sides? I only see pics for the minus side. The plus side doesn't have a dash next to it.

I guess I probably should re write the code to make that more apparent. Add a + to the plus side readings.
I checked the plus side as well but the pics were all negative it seems. Could also be due to me marking my rotor so I know when I've made one full revolution. The marking is more than likely on the negative side.

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