Control the UBTECH Alpha Robot Digital smart Servos (UBT-12HC) with ARC
How to add the UBTECH Alpha Servos UBT-12HC robot skill
- Load the most recent release of ARC (Get ARC).
- Press the Project tab from the top menu bar in ARC.
- Press Add Robot Skill from the button ribbon bar in ARC.
- Choose the Servo category tab.
- Press the UBTECH Alpha Servos UBT-12HC icon to add the robot skill to your project.
Don't have a robot yet?
Follow the Getting Started Guide to build a robot and use the UBTECH Alpha Servos UBT-12HC robot skill.
How to use the UBTECH Alpha Servos UBT-12HC robot skill
Control the UBTECH Alpha Robot Digital smart Servos (UBT-12HC) with ARC. The servos must be powered appropriately, and connected to the EZ-B v4 or IoTiny with the respective port. Visit the Config menu of this plugin to view the port configuration.
The Virtual Ports (V0..V99) in ARC can be assigned to the UbTech servos.
UART Ports
This plugin requires the RX signal wire of the servo be connected to TX of the selected UART or digital port (if Software UART is selected on IoTiny)
Hardware UART is for the EZ-B v4 only. Do not use software UART on EZ-B v4. View the EZ-B v4 datasheet to identify the UART ports (0, 1, or 2). EZ-B v4 datasheet can be found here: http://www.ez-robot.com/Tutorials/Lesson/18
Software UART should only be used with IoTiny
Default baudrate of UBTECH servos is 115,200
Bind To Virtual Servos
- The configuration menu also provides an option to select the Virtual Ports, which correspond with the ID's of the UBTech servos. If the UBTECH servo ID #0 is connected, select V0. #1 = V1, #2 = V2, etc..
Additional Info
- Discussion on these servos is here: https://synthiam.com/Question/3932
Custom Bit Settings There are 3 bits that seem to not be understood for the protocol. Since UBTech does not release the protocol for their products, the community is working to better understand what the parameters are. The configuration menu of this plugin allows you to set hardcoded values for those bits. The bits are for 5, 6 & 7.
Custom servo Position Mapping The UB Tech servos have their own position range, and we don't know what it is. So, the configuration menu allows you to specify the min and max positions for the range. This will be mapped to the ARC servo position range. Meaning, if you set the range in this plugin, it will be mapped to the range for all ARC servo controls.
Protocol Packet Code Here's a copy and paste from the plugin code. This is how the packet is being assembled to be sent to each servo. The values specified by you in the configuration menu are b5, b6, b7, mapLow and mapHigh.
@leonardo46
@DJ has limited internet access at the moment, but I wanted to ask you if you've tried what he suggested?
Modifying the action steps and delay may help by spacing the data out a bit.
Actions send a very large number of bytes (about 170) , much more than what's required for moving servos from a frame to the next one (20 bytes). This always happens , no matter how you set delay and steps. This causes uncertain positions for the servos. If EZ-B could send 20 bytes for each frame transition , spaced , say, 100-200 mS or more, things might perhaps work.
Look at the manual for the alpha Bluetooth servo protocol. I believe it’s 8 or 10 bytes to move a servo. Please do not type in all caps.
Ps, if you want to see the messages then connect to the ezb emulator. Set the emulation device (iotiny) and use your project.
I'm very ignorant about ezb products. I know and use ARC, but what's "ezb emulator" ? another PC software ( where can I find it ?) or a special function of ARC itself ?
:)
I'm ignorant. What program is this ??? what "machine" ???
Are you serious ? Look your windows / Start menu / Synthiam Folder