Arduino Code

I am designing rotary hopper counter for hardware. Using arduino mega, 4 digit 7 segment display, 7 momentary switches for user input, encoder on motor shaft, and digital high from proximity detector. 1.5ms would be fastest object detection rate. Code needs to: 1. control dc motor speed via encoder and pwm output hold rpm roughly. 2. select count input via momentary switch press. switch1 100, switch2 250, switch3 500, switch4 1000. switches should be able to add. (ie push switch1 and switch2 gives 350) must stop motor on count reached. via 1,1 sent to pwm controller (braking on motor driver). also "clear/cancel" switch, and "pause" switch, and start switch. Count input is via digital high from switch. this may be physical switch or input from ultrasonic or IR sensor. Display is 4 digit 7 segment red LED display program should detect a stall via encoder and reverse motor (send 0,1 to direction pins) for 500ms and then continue forward to unjam hopper. operation: 1. User selects count by pressing 1 or more of count selection switches. (Switch 1 selects 100, Switch 2 selects 250, switch 3 selects 500 and switch 4 selects 1000, switch press will add) result of each press is displayed on 4 digit led display so if switch1 is pressed, display will show "100" if user then presses switch 2 display will now show "350" etc up to 9999. no rollover past that. 2. user then presses start switch. This first changes display to show count progress which is initially "0" and then activates pwm drive and motor spins hopper and objects begin to trigger count. 3. Once count matches value set on display when start switch was pressed motor is braked to a stop. 4. display should continue to show count in case motor was not stopped fast enough and a few more items fell through counter then user would know and could adjust. clear/cancel switch should reset display to zero and stop motor by sending 0,0 to pwm control. Pause switch should continue counting items but send motor pwm to 0 letting it coast to a stop. Start button should cancel pause and restore motor to prior pwm setting.