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View Full Version : How to use a wck1111 servo (or any serial servo)



kiwibrisa
04-27-2010, 03:58 AM
Hi all. I have been trolling this site for a while and thought it was about time to sign up. Real mint site i have to say! Awesome info.
I am working on a humanoid project at the moment and have decided to use the wck 1111 actuator/servos. I am a complete noob when it comes to these serial servos it seems. Im quite happy with microcontrollers, drivers and dc motor type set ups but for this project im planning on using a lot of the pre-made controllers and servos etc.
So my question is how do i test/use them? Iv bought a couple and want to test stall currents how strong fast they are etc without buying a controller. There are 4 wires, gnd vcc rx tx which im sure you guys are aware of. What do i send to R and T? Does R receive info on where to go and T transmit info back on where it is?

Cheers

iBot
04-27-2010, 04:43 AM
The wck servos have a serial protocol which is described here: http://robosavvy.com/RoboSavvyPages/Robobuilder/robobuilder-creator-users-manual.pdf

It differs from the robotis, because it uses seperate TX and RX. You need to implement the protocol to read and write data to the WCK. Robotis have published there code for the protocol,, plus there are other implementations available.

What controller are you planning to use for the tests ? You can control direct from PC without controller using the WCK programming software, you just need an FTDI chip or similar to present the serial ports at ttl levels to the TX and RX,

kiwibrisa
04-27-2010, 04:24 PM
Thanks for the info. So an FTDI chip is USB to Serial? So if i get a usb to rs232 converter would i be fine? Or are there different types?

Would this work? http://www.jaycar.com.au/productView.asp?ID=XC4834&keywords=serial&form=KEYWORD

iBot
04-27-2010, 06:29 PM
The usb to rs232 converter will work, but you still need to convert to inverted TTL levels, so you will need a MAX232 or similar to do that.
I have used the FTDI TTL-232R-5V-AJ cable to go direct USB to TTL levels. This plugs into a small interface board I made with with wck connectors.

billyzelsnack
04-27-2010, 07:54 PM
If you have some sort of microcontroller setup already working that is probably the easiest way to talk to the servo since it's most likely already at TTL levels. Maybe add a pot to specify the desired servo position.

kiwibrisa
04-28-2010, 12:56 AM
Cheers iBot. I used a ST232 and its working mint now.