View Full Version : Help with AndyMark "Add a Motor" Set for the Sake of Wheelchairkind

07-31-2014, 10:53 AM
Hi guys, let me start out that 1) I am a college student, 2) my major is biomedical engineering and not electrical or electronics engineering, and 3) no one on my team knows anything electrical or, in this case, robotics. However, we are doing a very important project to help the disability community and are, because of the previous information, more stuck than a shirt on the back of a sweaty man. We need two 12 volt motors that can be controlled with a simple joystick like the ones you see in arcades. We were told by a man that knew electronics and robots to buy the AndyMark "Add a Motor" set as it had all the parts for a simple motor and all we needed to do was add some batteries (currently trying to test full load current), a controller chip (we have a computer engineer helping us with that), and a joystick (she is helping with that as well). Problem is: we got the kits in today (we ordered two since we need two motors), looked at it, and realized that even the simple part of this plan is far over our heads. We have confirmed that the motor does work, and we are using an 8 volt battery (the Talon SR Speed Controller can handle 6 volts at the least) just to test with and will take full load current measurements when we test with a 12 volt battery. The main problem we are having is where and how to wire everything to the Talon SR Speed Controller. Oh, and also the placement of the breakers. Actually, pretty much how to wire that kit up in general... I have tried to look up guides online, but they are more for the robotics specifics kits like the "RobotOpen Arduino Controls Kit, everything for two motors" and we don't want anything near that complicated. Could someone help us? We are running out of time since getting funding took almost a year and now deadlines are coming up. Could you be as specific as possible? This will be like telling someone who speaks another language how to land a plane. Also, if you could show us picture as well or videos or even schematics of the motor system, I would be very grateful. Thanks in advance! http://www.societyofrobots.com/robotforum/Smileys/default/smiley.gif

08-03-2014, 10:27 AM
So, another electric wheelchair? Or a remote controlled retrieval rover to pick up and/or move things on the floor (http://www.hsi.gatech.edu/hrl/project_dusty.shtml)?

The Talon SR manual (http://files.andymark.com/Talon_User_Manual_1_3.pdf) gives a decent overview of hooking it up and using it with anything capable of producing the PWM signal it needs. The RobotOpen wiring diagram (http://files.andymark.com/am-2301/schematic.pdf) gives a lot more than you need in your setup, but the basics apply to any microcontroller you use (all units must share the same ground voltage). An arduino could easily read the analog values of a cheap potentiometer based joystick, or the digital states of a limit switch based joystick, and then produce the PWM control signals for the Talon motor controllers using the servo library. Don't have any of the parts myself, so cannot give you much in the way of pictures or video.

Basically, you hook the two terminals of the motor to the output terminals of the Talon, you connect the PWM cable to a ground pin and PWM pin of the arduino (not sure if the Talon has internal regulator to get 5V from the battery power or needs 5V from arduino), then the negative terminal of the battery to the corresponding power terminal on the Talon (everything must have the same ground voltage / battery negative terminal). If the joystick uses potentiometers, you can follow any of the many arduino tutorials to connect them to some of the analog pins on the arduino and poll them using analogRead(). If the joystick uses switches, you can connect them to any of the free I/O pins on the arduino and poll them using digitalRead(). After you are sure the arduino is up and running the sketch with the PWM configured using the servo library, you can connect the positive terminal of the battery to the positive terminal of the Talon to power up the motor. The resettable fuse requires a fuse holder like the andymark power distribution board, but it may be safe to just to omit it.

P.S. wall of text is not easy to read.