NeedleKnows

Inspiration

Drug addiction is a critical medical crisis that’s affecting Americans everywhere, worsened by the increase in fentanyl in recent years. The issue is especially noticeable in densely populated cities like San Francisco where there has been an increase in the number of used and discarded needles that litter the streets. Every month there are 20,000 needles picked up a month by the San Francisco health and public departments (SF Chronicle). Contaminated, sharp needles can be dangerous to collect and make everyday life more dangerous for the homeless population, and thus we must come up with a safe and effective method for collecting these needles while city governments come up with effective support systems for the drug addiction crisis. Our group was inspired to design an autonomous robot to safely collect needles because we wanted to improve conditions in Los Angeles and San Francisco, cities we grew up in or close to.

What it does

Our robot NeedleKnows drives around cities and collects used needles to be safely discarded at a proper waste site. It begins gathering data about its surroundings with an ultrasonic sensor, then driving when it does not perceive anything in front of it. There is an electromagnet hovering close to the ground inside of the bot to pick up needles. When enough needles are collected to trigger the load sensor, an arm inside the bot moves the electromagnet with the needles attached and places them in a sharps bin. Additionally, one can drop a needle in from the top of the bot through a panel if desired. The sharps are then driven to the appropriate waste management site.

How we built it

For the drivetrain we designed a two-wheel drive with a castor wheel in the front for balance. It’s controlled with a 5V relay and an H bridge. The electromagnet is attached to an arm inside the robot with a joint containing two servos that allow for two degrees of freedom. The chassis was designed in SolidWorks, is made of acrylic, and manufactured using a laser cutter. A load cell is attached to the electromagnet to determine when enough needles have been picked up. Lights were added to the bottom of the chassis for extra visibility at night. There is an ultrasonic sensor located at the front of the bot. Most of our internal mountain was done with various types of tape and adhesive glue.

Challenges we ran into

Our first problem was determining whether or not a needle could even be picked up by a magnet, which was solved by finding a hypodermic needle for experimentation as a sample. We originally attempted to make our own electromagnet but quickly discovered that without an iron core, we were not going to generate enough force to lift the needles. Fortunately, we were able to acquire a different electromagnet. Moreover, our original chassis design was too limited in size to allow for the arm to swing across its entire travel arc inside of the chassis. We circumvented this challenge by increasing the dimensions of our robot, allowing for greater clearance.

Accomplishments we’re proud of

We are proud of our sleek recognizable chassis design which allows this product to be visible for drop-offs, even at night. We are also proud of our interior robotic arm capable of detecting how much weight it carries and transferring collected waste to an on-board receptacle.

What we learned

We learned that creating custom electromagnetics is quite difficult as it either heats the resistor or the battery used in the circuit quite quickly. We learned that to power a strong electromagnet, servos, and a drivetrain much more powerful batteries are required. Creating a very clear work timeline from the beginning and making sure everyone on the team has the same priorities is also pertinent. Most importantly, we learned that friendship is key to building a fun project and ultimately having a meaningful hackathon experience.

What’s next for NeedleKnows?

A computer vision system that allows the robot to quickly identify waste targets and travel to them directly rather than sweep a general area. Additionally, NeedleKnows seeks to develop a GPS reporting system, allowing members of a community to report hazardous waste that NeedleKnows can travel to and recover. NeedleKnows is also working on developing other end effects to pick up other forms of waste.

Built With

• arduinonano
• electromagnetism
• lasers
• servos
• soldering
• ultrasound
• wires