Electronics 12/14/08

Attendance: Ian

Agenda:

• Test LEGO Lamps hooked up to the NXT motor ports
  
• work on redesigning a circuit to use 8LEDs with only two digital bits on the prototype board

Today I met with Jeff and John; the team has been coming up with ideas of how to use light and sound for decoration. My first expiriment had three lamps each plugged into a motor port and I set them to different values to find if we could control brightness.  Even with a power of 5 the light was at it's highest intensity.  Upon looking at the code again we noticed that PID control was on, so because the lamps dont provide a response we had the same problem that we had with the DC motors earlier, after turning off PID control the intensity now changes relative to the amount of power we apply. 

After some simple testing of the lamps we took a look at a circuit John had made using 6 LEDs and the prototype board.  This circuit was very limited and simple because it used all six digital bits, one for each LED.  We came up with an idea that uses 1 IC and only two of the digital bits to control 8 lights.  It works because the chip passes the original value on to the next pin with each clock cycle so we can enter a pattern 1 bit at a time using an input pin and the clock pin.  We can program the clock to be pretty much whatever speed we want. So for example we can turn all the lights on by turning the IC's input pin on and then doing a number of rapid cycles of the clock.  All that remains after I assembled the circuit on our prototype breadboard, is for our team to program the nxt to talk to these lights.