Thursday, 3 January 2013

JAVA working beautifully - many thanks Dr Davison. 

Be Aware

When you install the new drivers (Lib32-usb and Java) for your USB robot arm, the OWI software you loaded from the CD will stop working.

The first test of the OWi USB Robot arm, using the Davison code and instructions, works fine. I just played with the USB board on my PC with only the motors and LED attached. Ok it's cheating, but I wanted to know if I could program it using my own Java code.

Now it's time to play with it and see if I can get a nice interface up and running.

(I am using Netbeans 7.2.1 on Windows Vista). I need to decide how I'm going to progress this so it can go mobile.
  • Do I stick with Arduino?
  • Do I move over to Raspberry PI and Linux open JDK Java JavaOne 2012?
  • Blue Tooth / RF RC control?
  • All of the Above?

I will list some limitations of the Robot Arm. Don't get me wrong, I don't expect the vendors to provide solutions to the limitations. At this price it is great value for money (~ £50). The next one up I found uses servos and an MCU for £150. But maybe I can improve it and have fun at the same time! That's Gampa's mantra.

The kit (as supplied) has no way of sensing or communicating the position of any of it's parts. This is risky for the mechanical parts of the arm and could cause wear, even failure. We don't want our 'bot to get a sprain do we? Some thoughts:
  • Gears just carry on grinding away when max-positions of motorised joints are reached
  • Gripper needs "touch" sensor
  • Motors and gears could wear out
  • Batteries are very heavy - replace with Li-Ion?
My idea is to suggest an Arduino and on-board sensors in conjunction with the Arm. The Arduino could sense the limit and stop the motor(s) when max-positions are sensed, overriding commands from the Java program. A bit like a reflex in mammals - no need to engage the brain (Java machine).

This may be a cheap and simple add-on implementation to the arm, irrespective of how it is being controlled, whether it's the vendor's software or a custom Java implementation.


  1. Many thanks for the brilliant Robot Arm review - we look forward to seeing you set it free! A video of the Arm in action would be great.

  2. Hi RapidRuss, thanks for the +ve feedback. It works nicely, will post some video soon. I was very pleased at the build quality given the price.

    I want to write some Java code to make it "perform".
    I'm working out a way to attach it to my robot car (the one that did the dancing) but that will take a long time, so before that I'll do a video of it on a static surface.

  3. Note the picture at the top of this page shows a manual controller. This was not supplied with the USB version. You just get USB control. However if you get the manual control version you can order a USB accessory kit from OWI (