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Author Topic: Modify servo with replacing P.O.T  (Read 3066 times)

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Offline offyTopic starter

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Modify servo with replacing P.O.T
« on: March 04, 2009, 07:14:55 PM »
I want to replace the P.O.T. Could I use a 1.62K OHM 1/4W 1% Metal Film in airman00 tutorial on how to modify a servo?

http://www.societyofrobots.com/member_tutorials/node/82

Offline Ro-Bot-X

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Re: Modify servo with replacing P.O.T
« Reply #1 on: March 04, 2009, 07:20:43 PM »
I have used 2 resistors, both 2.7k, in series, with the middle connection tied to the board where the middle of the pot was, just like in Airman's tutorial.
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Offline offyTopic starter

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Re: Modify servo with replacing P.O.T
« Reply #2 on: March 04, 2009, 07:23:29 PM »
Can I use a 1.62K

Offline Trumpkin

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Re: Modify servo with replacing P.O.T
« Reply #3 on: March 04, 2009, 07:25:41 PM »
Probably not.
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Offline offyTopic starter

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Re: Modify servo with replacing P.O.T
« Reply #4 on: March 04, 2009, 07:28:21 PM »
So the resistors go to the 5v and ground, than they connect and go down the middle one (pulse)

Offline Trumpkin

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Re: Modify servo with replacing P.O.T
« Reply #5 on: March 04, 2009, 07:35:27 PM »
Yep, connect one resistor to the left wire and the other to the right wire and then where they meet up connect it to the middle wire. Just like it shows in the tutorial.
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Offline offyTopic starter

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Re: Modify servo with replacing P.O.T
« Reply #6 on: March 04, 2009, 07:39:37 PM »
The tutorial image was kinda confusing. But does anyone know if I could use a 1.62k. I don't think it will matter. But I am new to this so...

Offline airman00

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Re: Modify servo with replacing P.O.T
« Reply #7 on: March 04, 2009, 08:21:22 PM »
Can I use a 1.62K

Quote
    * Two 2.2k resistors (actually, anything between 2.2k and 3.3k will work, as long as they are equal values)

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Offline offyTopic starter

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Re: Modify servo with replacing P.O.T
« Reply #8 on: March 04, 2009, 08:45:35 PM »
Oh, I think I need to buy some new resistors than. I really don't know, I soldered the 3 wires to the pot since they came off and it doesn't work, it seems like they are not connected...

Offline Soeren

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Re: Modify servo with replacing P.O.T
« Reply #9 on: March 05, 2009, 01:28:48 AM »
Hi,

Those resistors are nothing but a potential divider, so the only consequence in using 1k62 is a slightly larger current draw.
In other words, use whatever you have that don't suck up too much current. I'm not sure how high you could go, as I don't know the impedance of the input that sees the Vcc/2, (since I don't mess around using servos as motors), but I wouldn't be surprised to find a semi-high impedance (still, it probably cannot be too high, or it might be prone to picking up radio noise when used for R/C), but 10k resistors will very likely work.

Resistors/Current drain:
1k0/2.50mA
1k62/1.54mA
2k2/1.25 mA
3k3/0.75mA
Regards,
Søren

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Offline offyTopic starter

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Re: Modify servo with replacing P.O.T
« Reply #10 on: March 05, 2009, 02:09:18 PM »
Everyone says something different. I don't know if I should use the 1.62K or not.

Offline Trumpkin

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Re: Modify servo with replacing P.O.T
« Reply #11 on: March 05, 2009, 06:37:25 PM »
Resistors are not expensive, so I suggest you just go by 2.7k ones, just to be on the safe side.
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Offline offyTopic starter

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Re: Modify servo with replacing P.O.T
« Reply #12 on: March 05, 2009, 07:28:13 PM »
I used the 1.62k ones and it works fine. Thanks for all the help. If anything goes wrong I will be sure to buy 2.7k ones =]

 


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