 
          10. This is yet another unit with simplified controls.
        
        
          Speed is adjusted with the knob on the right. The
        
        
          larger green LED shows the power level, and the
        
        
          smaller LED next to it indicates direction. The Play/
        
        
          Record switch is to the left of the speed control. The
        
        
          LED and switch in the upper-left are for the block
        
        
          sync relay. When the relay is active and the block is
        
        
          unpowered, the LED is lit.
        
        
          10
        
        
          
            Another unit
          
        
        
          I built a second unit and show it here. The controls are:
        
        
          
            SPEED
          
        
        
          – a potentiometer that sets the speed of the train when
        
        
          in PLAY mode. Turn the pot left to speed up in one direction.
        
        
          Put it in the center position to stop. Turn the pot to the right to
        
        
          speed up in the other direction
        
        
          
            PLAY/RECORD
          
        
        
          – a toggle switch that selects the operation mode
        
        
          
            START
          
        
        
          – a pushbutton switch that can be activated by the
        
        
          ENABLE/DISABLE switch. If set to ENABLE the train will play
        
        
          PICAXE circuit part 2 - 8
        
        
        
        
          MRH-Jul 2014