Author Topic: $50 Robot with R/C ESC  (Read 2853 times)

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Offline mrtimbolognaTopic starter

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$50 Robot with R/C ESC
« on: September 05, 2009, 09:13:28 PM »
Greetings,

I am starting my research to use two brushless motors with R/C ESC's (that I already have from R/C planes) on my $50 robot board. As usual I started by just plugging one right up in place of one of the 2 servos, and besides it powering the board, i got no motor spin.

From reading a few posts (specifically http://www.societyofrobots.com/robotforum/index.php?topic=2641.0 and http://www.societyofrobots.com/robotforum/index.php?topic=5937.0) I understand that I must mimic the start-up frequencies or something that the ESC is expecting, as it would usually get from it's setup with the R/C receiver. I found a post talking about this, but not explaining how to do it. Could anyone help me understand it? I have seriously limited programming knowledge of C at this point, but I'm not at all afraid to play around in some code (I made minor adjustments to the $50 code and I know HTML / CSS / Applescript).

Another question would be, I have 2 x ESC and 2 x brushless motor. I assumed I would use both ESC, however they send 5V back through the JST into the $50 bot board, effectively powering it. If I plug in 2 ESC, would this be equal to powering the board with 10V?

Many thanks for your answers.
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Offline Razor Concepts

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Re: $50 Robot with R/C ESC
« Reply #1 on: September 05, 2009, 09:29:16 PM »
At start up you must send low signal (1ms pulse) until the ESCs are armed.

To run two ESCs, that would not be 10v but 5v in parallel, and they can fight each other - so disconnect the center power line from one of the ESCs.
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Offline mrtimbolognaTopic starter

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Re: $50 Robot with R/C ESC
« Reply #2 on: September 05, 2009, 09:45:42 PM »
Awesome Razor thank you.

So maybe you saw this coming - how would I send the 1ms pulse until the ESC's arm in my code? I understand if your gonna say, go search, which is what I'm about to do, but any thread to point me towards or info is appreciated.

Also, when you say disconnect the center power line from one ESC, I then assume I am powering both ESC's with seperate batteries? Is there anyway around that, I have a 11.1V 1500 mah LiPo I would love to use as the single power source.
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Offline Razor Concepts

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Re: $50 Robot with R/C ESC
« Reply #3 on: September 06, 2009, 12:40:25 AM »
Use that lipo to power both of the ESCs, that works perfectly. Just on one of the ESCs, on the 3 pin futaba/jr connector, disconnect the power line.
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Offline mrtimbolognaTopic starter

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Re: $50 Robot with R/C ESC
« Reply #4 on: September 06, 2009, 07:34:45 AM »
Oh crumb I  just realized a major flaw in my plans.....

R/C airplane ESC's only have forward, no reverse, and I was planning to use them for Differential Drive. So much for that idea.
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