View Full Version : [Question(s)] Beginner Looking for some help with simple Tracking Robot

01-21-2012, 12:47 PM
Hello all,

The device I am trying to build is pretty simple but I am having a hard time nailing down some exact details. The device is an autonomous seed planter. Small scale, it will basically be on two runners covering a total distance of about 4ft. It will traverse the runners using one DC motor powering a driveshaft. It has an additional DC motor which basically just shoves a tube into some planting soil and leaves a seed behind. In addition I would like to be able to control these actions remotely ie the device will be set up in Utah but I'd like to command it from Georgia.

So my questions are:
What is the best way to control these two motors using a PC? In terms of controllers, I have seen some set-ups like this(http://www.pc-control.co.uk/motorbee_info.htm) which list a servo as optional. And the one that led me to this forum here(http://forums.trossenrobotics.com/tutorials/how-to-diy-128/control-a-dc-motor-from-your-computer-2283/) which leads me to believe I need both a motor controller and a servo controller.
What is the best way to host the commands remotely? Should I host them to a webpage or set up the robot PC as a virtual machine?

Thanks so much for any help you might can provide.

01-22-2012, 12:18 PM
Anyone have any ideas? I'm sort of at a loss and the more I look the more I seem to confuse myself. Let me know if you need more information

01-23-2012, 01:08 AM
If there will be a PC on whatever it is that is connected/supporting the seed planting gantry, and this PC has an internet connection and an available USB port, then (unless you want to build your own) an Arduino (http://www.trossenrobotics.com/p/arduino-uno.aspx) (or older version (http://www.trossenrobotics.com/p/arduino-duemilanove.aspx)) with a Motor Driver Shield (http://www.trossenrobotics.com/store/p/6405-Ardumoto-Motor-Driver-Shield.aspx)would probably be the quickest and cheapest way to get going. The L298 dual H-bridge motor driver IC on the motor shield can provide up to 2 amps for each motor and there should be many different code examples online for using the shield with an Arduino. Basically, you would program the Arduino to control the motors based on sensor input and a serial data stream from the PC (TTL UART on the Arduino to USB via the onboard FT232RL or ATmega8U2 depending on Arduino model). The sensor feedback (if any) would hopefully prevent malfunctions and could easily be sent back over the serial line to the PC to be sent to the remote control station. You also can easily control hobby servos via PWM channels on the Arduino (plenty of code examples online).

If you do not have a PC to access, you could instead use the TXD and RXD of the UART on the Arduino (broken out to the header) to connect to a radio transceiver module with a TTL UART (XBee being very popular but requiring level conversion from the Arduino's 5V to the Xbee's 3.3V, with some very long range/low baudrate versions available).