Introduction: Gundriver- an Electric Screwdriver Inside a Toy Gun

I discovered this a little while ago, and I immediately wanted one. Until I saw the price. I didn't want to pay $40.00 plus shipping for something I could easily make myself. So I got to work on my own, and I am very happy with the result. I built it for a tenth of the cost and was able to choose my own shape and look for the gun.

Step 1: What You Need:

Supplies
- Toy gun
- Duct tape
- Wire
- Battery pack
- Superglue
- Motor
- Momentary switch
- Pencil eraser
- The shaft of a multi-bit screwdriver OR an extension bit
- Forward/Reverse switch (if you have one skip step 2) OR if you don't have one:
                                                                                                                                 - 2 small nails
                                                                                                                                 - 2 CONDUCTIVE
                                                                                                                                   magnets
                                                                                                                                 - Magnetic tape
                                                                                                                                 - A 2x2 Lego brick
Tools
- Hot glue gun
- Rotary tool
- Soldering iron and solder
- Screwdriver
- Drill

Step 2: Making the Forward/Reverse Switch

*Skip if you have a Forward/Reverse switch*

- Unfortunately, all the switches I looked at weren't cost effective. I couldn't really find any nearby, so I had to look elsewhere. Unfortunately, shipping caused what should have been a cheap, easy to get part to become too expensive, so I had to make my own. If you are making your own switch make sure your magnets can conduct electricity!!!
- Put a piece of magnetic tape on the bottom of the Lego brick. 
- Bend the nails at 90 degree angles near the tips, so that if the nails are attached to the sides of the magnet the tips will touch. (Look at the second last image.)
- Tape a piece of wire to each of the magnets. Glue the magnets wire side down to the magnetic tape. 
- Solder the wires attached to the magnets to the battery pack.
- You will connect the nails to the motor later

How it works: the nails are connected to the motor and the magnets are connected to the power source. Since each magnet is connected to a different terminal on the power source and each nail is connected to a different terminal on the motor the flow of current can be easily changed. Say both Nail 1 and Nail 2 are connected to the positive magnet. Nothing happens. But if Nail 1 is slid forward to touch the negative magnet the motor starts to spin in one direction. Conversely, if Nail 1 stays touching the positive magnet and Nail 2 is slid forwards to touch the negative magnet the motor will spin in the opposite direction, because different terminals on the motor are touching different terminals on the battery. 

Step 3: The Motor

- Use the rotary tool to cut the shaft of the screwdriver/extension bit a pencil eraser's length below the magnet that holds the bit in place. If it isn't hollow, drill it out. (But be careful not to drill through the magnet.)
- Superglue the eraser into the screwdriver/extension bit shaft.
- Force the motor shaft into the center of the eraser and superglue it.

Step 4: Preparing the Gun

- Take apart the toy gun.
- Use the rotary tool to clear a space for the motor near the muzzle and for the battery pack in the handle.
- Drill out the center of the orange muzzle cap, then use the rotary tool to remove the rest of the plastic inside the outer ring.
- Hot glue the momentary switch above the trigger so that when the trigger is squeezed the switch is activated.
- Make sure the motor shaft can fit through the muzzle. If it can't take the rotary tool and grind away at the muzzle until the motor shaft can easily spin in it. 

Homemade Fw/R Switch
- Get the nails you bent earlier and touch the tips together, making a U shape. Measure the distance between the heads of the nails. Drill two holes that far apart near the hammer of the gun, one on each half. 

Purchased Fw/R Switch
- Use the rotary tool to cut out a space for the Fw/R switch near the hammer of the gun. 

Step 5: Putting It All Together

Homemade Fw/R Switch
- Solder a wire to one of the nails. Stick both the nail and wire through the hole drilled in the half of the gun where the momentary switch is glued. Solder the wire leading from the nail to the momentary switch. I didn't do this, but it's a good idea; once the wire is soldered to the nail wrap the part of the nail before the bend in duct tape to prevent short circuits.
- Solder a wire to one of the motor terminals. Solder the other end of that wire to the momentary switch.
- Solder a long wire to the other nail and stick both the nail and wire through the hole on the other half of the gun. Solder the wire to the other motor terminal.
- Arrange the Fw/R switch so that the side of the Lego brick lines up with the hole you drilled for the nail on the same half of the gun as the momentary switch. Make sure it is level, and the magnets are parallel lengthways to the back of the gun. Glue it in place.
- Glue the motor in place with about 1/2 of an inch of the shaft protruding from the muzzle. Glue it on the same half of the gun as the momentary switch.
- Put the battery in the handle.  
- Hold the gun closed. Make sure one nail is in contact with each magnet. Squeeze the trigger to test. If the motor doesn't spin, take apart the gun and check the circuit.

Purchased Fw/R Switch
- Insert the Fw/R switch into the hole you made earlier.
- Solder the wires from the battery pack to the Fw/R switch.
- Solder one wire from the motor to the Fw/R switch.
- Solder the other wire from the motor to the momentary switch. Then solder the other lead of the momentary switch to the Fw/R switch.
- Glue the motor in place with about 1/2 of an inch of the shaft protruding from the muzzle. Glue it on the same half of the gun as the momentary switch.
- Put the battery in the handle. .
- Hold the gun closed and squeeze the trigger to test. If the motor doesn't work take the gun apart and check the circuit. 

Step 6: Testing

Homemade Fw/R Switch
- Screw both halves of the gun together. 
- Pull both nails back. Push the one on the left forward and pull the trigger. Find out which way it spins. Label the direction. The other nail pushed forwards will make it spin in the other direction, so label it as such. Test with the other nail forwards just to make sure the circuit works. 
- Place the remains of the muzzle cap around the motor shaft. Superglue it to one half of the gun. 

Purchased Fw/R Switch
- Screw both halves of the gun together. 
- Figure out which way the buttons on the Fw/R switch make the motor spin. Label them as such. 
- Place the remains of the muzzle cap around the motor shaft. Superglue it to one half of the gun.