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sparkfun Open Servo

 
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boogui



Joined: 18 Aug 2010
Posts: 2

PostPosted: Wed Aug 18, 2010 12:32 pm    Post subject: sparkfun Open Servo Reply with quote

hi everyone

i'm new to open servo, i just bought one from sparkfun, wich seems to be a V2.7 . there is no instruction to make it work, so i need a little help.
i'm currently sending a +5v I2C signal from a pic2420, is the OS at the same line level (no 3.3v)?
what is the address, i've tried fro 0x10 to 0x20, no move...
is the firmware already loaded, cause i can't get any sign of life in it, even the motor don't react at power up, is there a way to control. i did test 5v at the output of the regulator, i'm powering with 7.5V 1amps.
my I2C looks like, start, adress,0x10 (for moving to position),0x03,OxD4 (position),stop is it correct?
best regards

Rolling Eyes Rolling Eyes Rolling Eyes
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jharvey
co-admin


Joined: 15 Mar 2009
Posts: 361
Location: Maine USA

PostPosted: Thu Aug 19, 2010 8:33 am    Post subject: Reply with quote

I'm not very familiar with that version, some things I know about the OSV3 version is that it needs a rock solid 7.2v supply, just like RC battery packs supply. Some steps required to make it go to a position include setting the PID values or at least the P value, setting a position, and turning on the motor PWM.

A basic read of the position(s), that changes as you rotate the servo shaft might be a good first step. That would help ensure you have working communications, ect.

I know that you can use the PIC I2C, but I'm not that familiar with that approach. I'm using an OSIF from robotfuzz.

http://robotfuzz.co.uk/OSIF

It's powered via USB so I would say yes you are good for 5V I2C. This comes with test software that will allow you to confirm basic operations of the servo. In my case I found I had a bad power supply. My bench supply typically gets cranked up to a 5 amp limit, and I know it won't work on several lower current limits. I'm not sure if 1A is to low or not.

I know the OSIF software has a scan option that will list all devices on the I2C. This is where you find the address. Mine came with a default at 0x10, so yours is likely 0x10, but I would recommend scanning the bus.
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boogui



Joined: 18 Aug 2010
Posts: 2

PostPosted: Thu Aug 19, 2010 8:57 am    Post subject: Reply with quote

thank you jharvey

i just ordered the OSIF, hope it will be usefull

i 'll try with another power supply or a battery packs.

Shocked
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