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Offline tjpark1111Topic starter

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newb questions
« on: January 15, 2008, 08:29:14 PM »
do i need to use the same brand servo, transmitter, and receiver for the whole thing to work?
usually i see transmitters and receivers coming with crystals, but they say they'll pick a a random channel. since you need to have the same channel, is it good to buy RC packages instead of buying the trasmitter and the receiver separately?

Offline airman00

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Re: newb questions
« Reply #1 on: January 15, 2008, 08:33:13 PM »


brand doesn't matter frequency does. But be warned : you need exact frequency1 if the transmitter says 27mhz its probably not exactly 27mhz but 27.00007 mhz or maybe its 27.5 mhz ?

buy the packages together that way you know for sure it works
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Offline tjpark1111Topic starter

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Re: newb questions
« Reply #2 on: January 15, 2008, 10:28:07 PM »
alright i got ya. r u sure brand doesn't matter? ive been looking through the receiver page and all of them say ONLY COMPATIBLE WITH FUTABA. ONLY COMPATIBLE WITH JR SERVOS. ????
http://www.robotmarketplace.com/products/0-HRC156751.html
is this a good choice? the only thing im confused with is the servos that the package comes with are 72mhz version??.... the trasmitter/receiver is 75mhz.... ??
« Last Edit: January 15, 2008, 10:28:41 PM by tjpark1111 »

Offline airman00

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Re: newb questions
« Reply #3 on: January 16, 2008, 05:59:50 AM »
they are both 75 mhz (since 72mhz is reserved for flying r/c vehicles)

It looks like a good set

the reason they are compatible with only some servos is because sometimes the servos have different pulse ranges

for hitec it could be from 100- 200 , for futaba is could be 100-150 , etc.
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Offline Trumpkin

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Re: newb questions
« Reply #4 on: January 16, 2008, 09:40:12 AM »
That looks like a very good RC package. Good price too.
Robots are awesome!

Offline tjpark1111Topic starter

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Re: newb questions
« Reply #5 on: January 16, 2008, 10:00:15 AM »
one thing that's been nagging me: in some robot videos, i see some differential systems that are a bit too overpowered. the person would flick the transmitter for like half a second and the robot would turn too far to the left, or right, or goes forward too much. that would be REALLY annoying espeically in small environments like the competition im participating in. is there any way i can control the speed? is it automatiicaly controlled (push forward on transmitter all the way = fast, push forward half way = half speed?)

Offline airman00

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Re: newb questions
« Reply #6 on: January 16, 2008, 01:05:42 PM »
if its the receiver has speed control/ controls servos then its however much you push on joysticks,, thats how much the servo gets
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Offline SmAsH

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Re: newb questions
« Reply #7 on: January 16, 2008, 01:52:51 PM »
yea i had trouble when i attempted this a few years ago :'(
Howdy

Offline tjpark1111Topic starter

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Re: newb questions
« Reply #8 on: January 16, 2008, 06:09:25 PM »
i called tower hobbies tech support they said receivers don't have such thing as "speed control" so full power will be delivered to the servo at all times. the newbie guide tells me to double the torque that i THINK i would need, but im really worried that'll ill get TOO MUCH power and whenever i try to use my arm itll just go from 0 to 180 degrees rotation in like 1 second so i have no maneuverability at all. how can i get my robot to operate like the wall climbing robot that the admin made, where all the movements are smooth, nothing jerks because something is too fast/powerful, etc.

Offline tjpark1111Topic starter

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Re: newb questions
« Reply #9 on: January 19, 2008, 09:58:06 PM »
HELP HELP HELP!!!!!!!!!!!!!
can you use a 6V battery on a receiver and all of the servos will receive 6V? cuz it says on the guide receivers should be powered by 4.8 (~5V) batteries and if you want more voltage to your servo, you hook it up to a y-harness, which i still don't understand how it works....
if i use a y harness, do i need to attach a battery to each servo i plug into the receiver? and also, i looked up y-harnesses and it's supposed to be used to split the signal among 2 servos, not for the purpose stated on the guide....

Offline SmAsH

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Re: newb questions
« Reply #10 on: January 19, 2008, 10:10:43 PM »
yea i think you shouldnt use the 6V battery if it says not to. maybe use a seperate battery for the servos and use the y harness.
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Offline ed1380

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Re: newb questions
« Reply #11 on: January 19, 2008, 10:13:46 PM »
a receiver should be ok with 6v

normal servo's will fry if you give them over 6v

a y-harness is the same as splicing into the signal cables from a servo
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Offline tjpark1111Topic starter

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Re: newb questions
« Reply #12 on: January 19, 2008, 10:17:54 PM »
by the guide, i meant the SOCIETY OF ROBOTS guide. just so im knowing this right, and since none of the guides mention it - do i just plug in the servo into my receiver and that's it? the power is automatically supplied to the servos from the receiver's power?
so i can plug in a 6V battery to a receiver, then plug in 3 servos into a 3 channel receiver, and all of the servos will work just fine?
also, i want to get a power recommendation from you guys, since the calculators are useless for my application. i have a 1/4 scale servo that can do 300+ oz/in torque and 2 servos with 80+ oz/in torque. would 2300~ mah suffice?
last, since ed said over 6V would fry a servo, should i use a voltage regulator?
« Last Edit: January 19, 2008, 10:25:20 PM by tjpark1111 »

Offline Admin

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Re: newb questions
« Reply #13 on: January 25, 2008, 08:40:05 PM »
Quote
how can i get my robot to operate like the wall climbing robot that the admin made, where all the movements are smooth, nothing jerks because something is too fast/powerful, etc.

I will admit a lot of that was hours of operator practice ;)

Quote
so i can plug in a 6V battery to a receiver, then plug in 3 servos into a 3 channel receiver, and all of the servos will work just fine?

yeap

for your torque questions, read this:
http://www.societyofrobots.com/robot_faq.shtml#select_motor

 


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