Working Redstone Vending Machine

I have finally finished making a working redstone vending machine that you have to insert a item to unlock the buttons. Here are some features...

• Must insert an item into the machine to collect.
• Can click the buttons more than once, but must wait 3 seconds before clicking again. (3 second delay on the repeaters)
• 3 Items to dispense.
• Do Not insert mobs into machine, will crash the redstone machine.
• Can Insert any block or item into dispensers

Items used

• Wool (3 colors)
• Redstone Dust
• Redstone Repeaters
• Dispensers
• Hoppers
• Water Buckets
• Stone Blocks
• Stone Slabs
• Iron, Diamonds, Gold Blocks
• Iron, Diamonds, Gold Ingots
• Buttons