2/27/2012

Today in class we spent the time finishing up our programs so our robots will write our initials on the floor.  The letter my robot had to write were CJW.  Over the weekend i disassembled the right wheel and reassembled it, being more careful to make sure the motor mount wasn't rubbing any of the exposed gears on the motor.  Today when I went to test the robot both wheels worked fine, so I suppose that reassembling the motor worked.  We also received a new power cord with a smaller diameter that fits better in the power terminal on our circuit board.  I made small adjustments to the program and did an official run at the end of class. 
           The three pictures below are different angles of my finished robot

This video is of the robot making CJW.  The letters are formed more vertically than horizontally. 

2/22/2012

Today in class we discussed how to use drivers to power devices that require more power than the microcontroller can supply.  We also wired in some LEDs on our bread boards and used pwnouts to make then dimer and brighter.  Then our next assignment was to program the robots to write our initials on the floor while incorporating speed control.  I ran into some trouble though because the right motor wasn't responding well when it wasn't receiving full power.   Once I reduced it's power it would lag much more than what was programmed.  Dr. B. suggested a few things I could try to identify the problem but I'll have to work on them over the weekend.

LEDs wired in from the microcontroller to the driver

2/20/2012

Today in class we dissembled out robots from the previous assignment.  We removed to servo motors we were using and installed gear motors. We solder wired onto the leads of the motors as well as a capacitor going across the leads.  The other ends of the wires were put into crimp pins and then put into a 2 pin connecter so they can be plugged into the breadboard. We also discussed Brushed DC motors and Brushless DC motors, how they work and the differences between them.  We also talked about the different kinds of brushless DC motors such as step and half-step motors.

New motors with wires and capacitors soldered on

Top view of robot with old wiring removed and the other breadboard added

Rear view of new motors.

2/15/2012

Today in class I finished programing my robot to go through the maze.  I had to program in the final straight shot.  Then I wired in the buzzer onto the breadboard and programed it to make a short beep once it reached the end of the course.  The first video below shows the robot making it way through the course.  After we tested the robots we went over new material in class.  We went over the "dirs" command to help simplify our program went we have a lot of outputs we need to turn on and off.  The second video shows some LEDs being turned on and off in a loop in a simple program using the dirs command.

2/13/2012

Today the class time was dedicated to programing our robots to navigate through a maze.  We had to use time when programing the robots, which means instead of using sensors or speed control we had to tell it to go forward and left or right for a certain number of seconds.  This method can take time because you basically have to make an educated guess as to how long to tell the robot to go forward, program that, then test.  The series of directions in the maze are, straight, right, straight, left, straight, left, straight, right, straight, right, left and finally straight to the finish.  Once I created the subroutines for it, it was just a matter of putting them in the correct order and with the correct times.  When class ended I had all of the turns expect for the last one programed and timed.  During next class I'll have to finish that last turn as well as wiring in and programing the buzzer that is supposed to sound when the robot reaches the end of the maze.  The video below is a recording of one of the many test runs I did during class today.  I had the robot programed to navigate about half of the maze at that point.  You will see that if definitely needed some tweaking.

2/8/2012

Today in class we were given motor and motor mounts that were not included in our kits.  We attached those onto the robot body.  We discussed how to make connections from the PICAXE to the motors by using the breadboard.  We also talked about wiring in the buzzer.  After that we discussed bits, bytes and words and the differences and uses for each when programming.  After that we worked on wiring the motors to the PICAXE. 

Closer look at mounted motor and wheel

A look at the mounted motor and wheels

                                                      

Wiring for motors

Closer look at the wiring

2/6/2012

Today in class we spent some of the beginning of class putting the final touches on our circuit boards so they would be in working order for programming.  We discussed the basics of using our breadboards and how they are used to test and prototype.  We also discussed the differences between "sourcing" and "sinking" and how each configuration can be used.  We used are circuit board along with a breadboard and a simple program in PICAXE to cause an LED to blink on and off.  Using the breadboard, we made a circuit using a resistor and LED then wired it to our circuit board for power and the micro controller for instructions.  While we were writing the program, we learned some of the words used in PICAXE such as high, low, pause and symbol.  We wired this circuit to demonstrate both sourcing and sinking.  The last item we talked about in class was servo motors and Pulse Width Modulation (PWM).

 

In the above picture a connection is made to the circuit board from the laptop from the three pin connector on the board, through the modified DB9 cable, which connects to a USB adapter and finally into the laptop.  Power is supplied by the 9.6 volt battery.

The video above shows the result of the first program we wrote for our circuit boards.  The LED turns on for two seconds then turns off for two seconds.  This will repeat until power is turned off to the board.

2/1/2012

Today we continued our work on our circuit boards.  I finished adding the final components to the board.  After I finished soldering on the last pieces, I wove two pieces of blue wire through four holes, which had to be drilled bigger, and soldered one to the power terminal and the other to the diode at the bottom of the board.  I also set the chips in their sockets, a Uln2003 darlington array, a L293NE driver and a Picaxe 40x2 micro controller.  Next I soldered the toggle switch to the end of the blue wires, then put heat shrink over those solder joints.  Next I began to work on DB9 programming cable.  For our purposes we only need the 2, 3 and 5 pins.  I stripped the grey outer insulator and then the insulators of each individual wire.  I placed a piece solder in the number 2 socket then used the mulimeter to see which wire went to socket 2.  I did the same thing for the number 3 and 5 sockets.  After I had the correct wires I placed crimp sockets on each wire, so they can be connected to the 1x3 connector on our circuit board.  They female end of the DB 9 cable will be plugged into a USB adapter then plugged into our laptops so we can program our circuit boards.  After I finished the cable I assembled part of the robots body.

Underside view of soldered blue wires

Blue wires woven into holes in board

Toggle switch

Top view of chips in place

     

Crimps on wires leading to the 2, 3 and 5 sockets

Stripped DB 9 cable

         

Side view of robot body

Top view of robot body