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Electronics => Electronics => Topic started by: Its_Friday on February 11, 2009, 07:46:19 PM

Title: Servos are running slow
Post by: Its_Friday on February 11, 2009, 07:46:19 PM
I am using the axon microcontroller. When i plug in one servo, it runs at a decent speed. But when i plug in a second servo, for 1 second they run at normal speed, but then they slow down. They maintain that slower speed.

Why can one servo run fast, but 2 servos can't? They're hooked up to the microcontroller, and the microcontroller is hooked up to a 7.5 volt battery pack. My best guess is that the batteries can't provide the needed amperage. Whatever the problem maybe, how can i fix this? ???
Title: Re: Servos are running slow
Post by: Jdog on February 11, 2009, 07:58:45 PM
Try plugging in the 2 servos and measure the voltage of another output port, turn on the axon and see if there is a drop in voltage. If not Try it with a different battery pack and see if it still happens. You could even use a cheap $2 4 AA holder battery pack and try that. I know that 4 AA batteries definitely has enough amperage so try that and report the results. If that doesn't work, try writing a program to control three servos and read one adc port and print out the data, plug in your two servos and make a jumper wire from the signal wire of the other servo port to the input wire of the adc port and analyze the signal with the SOR Scope.
Title: Re: Servos are running slow
Post by: Admin on February 11, 2009, 11:26:48 PM
Quote
the microcontroller is hooked up to a 7.5 volt battery pack
what type of battery, and whats the mAh on it? is the battery fully charged?
Title: Re: Servos are running slow
Post by: Its_Friday on February 12, 2009, 02:13:49 PM
Quote
the microcontroller is hooked up to a 7.5 volt battery pack
what type of battery, and whats the mAh on it? is the battery fully charged?
It's a 7.5V 1200 mAh NiMH Battery Pack
Title: Re: Servos are running slow
Post by: Admin on February 12, 2009, 08:02:15 PM
Hmmm what servos are you using?

This battery should be enough . . . is it fully charged?

Are you controlling the servos through the ADC pins or the non-regulated pins?
Title: Re: Servos are running slow
Post by: Its_Friday on February 12, 2009, 09:02:14 PM
I figured out the problem.The battery is no good. Even though i measure it at 7.5V right out of the charger, it can't last more then a minute when running the servos. Thankfully i bought a spare battery that works properly.