This is a Test of our project about two weeks ago. Our group hooked up a motor that was created in a machine shop downstairs of Darwin. Then after the machinest John helped us fit a wheel to an engine that can run upto 12volts. We wanted to test it out, but didn't want to use our battery we bought. So our group went to Salazar 2003 and used the DC power supply to run our motor. This is the footage of our test, sorry the footage isn't of best quality, but the only recorder we had was a cell phone. Have fun watching.

We also realized after running our test that we only need 3volts to shoot twelve feet. Since we bought a 12volt battery, we're thinking of getting a 3 or 6 volt battery. The reason for this is the fact that we tried to hook up a potentiometer to regulate the voltage drop accross our engine, but we ended burning up the potentiometer because the wattage was to powerful. In order to have a potentiometer that won't burn up we are thinking of turning down our potential voltage to 3volts to lower the power consumption (because V*I=P). This we are thinking will keep our potentiometer from burning up but will also give us control of the speed, which in turn changes the possible distance the ball can travel. Giving us the ability to shoot roughfly between 15 - 0 feet.

Es 110 Progress Report October 21, 2010

We have currently revised our plan for our throwing machine, due to some issues with the roller which will be discussed later.  Currently our design is to use one motor and place it above the track where the ball can just squeeze under it to achieve some velocity.

We have aquired a piece of drainage pipe which will be used for our track.  The downpipe is where the planned hopper/ solenoid will be placed.  It measures 12 and 7/8" when inserted into the elbow.

For the exit pipe we used 10" of the same pipe with approx a 1.5" slit cut out to put the wheel in.  The exit pipe is currently epoxied to the elbow joint as it must be perfectly aligned for the ball to roll through smoothly.

Construction of the base for the design must commence.

In order to attach our wheels to the 12 V DC motors we acquired, we had to go to the machine shop and get John's help.  Scott and I were able to create two pieces of aluminum which would pressure fit inside of the wheel.  The aluminum piece had a part which fit inside the wheel and a lip which sat inside the wheel on the plastic.  The diameter of the aluminum piece measured 0.780" and the diameter of the lip was 0.872".  The length of the part is 0.850" and the length of the lip is 0.282".  After completing the piece on the lathe, we were able to thread it to the motor.

After I was able to use a Shimpo DT-105 tachometer to measure the speed of the wheel.  At its max power the motor ran at 122 Revolutions/Sec with the wheel on it.  We had theorized that one motor might be powerful enough to suit our needs, which was later confirmed at our tests last Thursday in the lab.

The lab test on Thurs revealed that the motor was drawing about 2.6 Amps when the output is around three volts.  We were able to launch the ball in excess of 20 ft easily with the motor turned up to a higher voltage.

We were also able to test a switch for the motor which worked beautifully.

The only issues we ran into were keeping the pipe straight when deploying the ball (which hopefully will be solved with the epoxy) and using other balls than the one we intend to. Which is a foam ball.  When using tennis balls the amount of torque put onto the wheel was enough to get it to slip and eventually come off of the motor.  This issue should be looked into.  I feel it is good that there is some sort of protection for the threads to not get stripped out, but we cannot afford to have the wheel come too loose.

Which brings me to the issue of why we decided to go with the one motor setup, since the motor threading was really designed for one way operation, when the voltage is reversed, the motor is so fast that the wheel torques off of the threading when voltage is stopped, ie when power is cut to the motor the wheel will spin off if it's not going the proper direction.

Another possible issue is the fact that we only have one foam ball to test.  I am finding it very difficult to find other balls like it.

What is needed for project completion is a potentiometer for the motor since it really needs to be turned down, completion of the frame, and hopper assembly.

So far though I feel we have a decent start to the project.