Statistics show that 40% of convicted murders had alcohol present in their systems at the time of the crime* and guns were the primary weapon of choice during these homicides. Our team aims to decrease the frequency of gun violence involving perpetrators that are under the influence of alcohol by physically blocking access to the trigger of the gun.


What it does

The gun’s trigger has two, 3D printed “trigger-blockers” that prevent anyone who is under the influence from pulling the trigger and firing the gun. The gun initially begins in a “locked” state with the trigger-blockers activated. For access to the gun, a user must verify sobriety by blowing on to the alcohol sensor grove. If no alcohol is detected, the trigger-blockers, located on either side of the gun, will rotate to the unlock position. 2 servo motors power the trigger-blockers and enable to rotation of the blockers when the gun is ready to be used properly. If alcohol is detected on the user, the trigger-blockers will remain in place and deny access to the firearm.

How we built it

Since we could not use a real gun, we decided to implement this on a Nerf Gun. We 3D printed 2 trigger-blockers and mounted them on servo motors. We then connected the servos to an Arduino 101 on digital IO pins. We had to use a breadboard to connect multiple servos to a power source. We also connected a Grove Alcohol Sensor to the Arduino as well. We then taped everything together. We, then implemented the logic mentioned in the What it does section using the Arduino IDE. We tested it by rubbing some alcohol on a tissue and putting it in the vicinity of the sensor while blowing through it to simulate alcoholic breath.

Challenges we ran into

  • Limited availability of the Dragonboard
  • Limited availability of hardware
  • 3D printer lost alignment
  • Servos not running on a 5V source

Accomplishments that we're proud of

  • Getting the alcohol sensor to work.
  • Managing wiring with limited resources
  • 3D printing the flaps
  • Having a functional prototype
  • Teamwork
  • Having fun

What we learned

We learned how to use Cura, a new 3D printer software. We learned how to use the alcohol sensor. We learned how to use servo motors. We learned that we could implement a geolocator code using HTML. We learned that hacking is hard and we like sleeping in beds.

What's next for GunLock

The team hopes to incorporate a Geolocator for our prototype in the future. The geolocator will be programmed to detect when the user is within 1 kilometer of any school/university and immediately activate the trigger-blockers. Once the trigger blockers are activated, they will remain locked until the user outside of the school zone. We plan on using Microsoft's Face API to detect if the gun is pointed at children and to lock the trigger when necessary.

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