The A.F.M was designed to aid combat medics in battle. Combat medics are a vital part of a functioning army. They are responsible for providing first aid and frontline trauma care in a battlefield. Due to the high importance carried by medics, they should not be put in high risk situations. Autonomous Field Medic for Search and Rescue Recovery of Victims, or A.F.M., has a variety of functions that helps get rid of this problem and alleviate many of the other problems a medic has. The A.F.M prevent medics from endangering themselves in battle. The A.F.M. will transport severely injured soldiers to the Medic, so the medic can tend to them in a safer place. It can perform this task by deploying a mat which the soldier would lay on, and transporting the soldier back to the medic. The A.F.M is also used to carry much needed supplies that a medic may need. Overall, the Autonomous Field Medic has a variety of functions that makes it a very beneficial device for medics.
Gears Educational System - 2 Heavy Metal Chassis
4, HB 25 h-bridges
2 DC Motors for gurnee deployment mechanism
4 DC motors for drive system
Camera swivel stand
Electronic contain box
¼ x18” screw
Step 1: Chassis Assembly
Join together 2 HMC Heavy Duty chassis. see picture on the HMC chassis for full assembly .
Step 2: Top Aluminum Plate
After the HMC chassis was assembled , 3 aluminum pieces were attached to the top of the chassis to make a platform. On this platform the electronics and gurney deployment mechanism are placed. The platform also serves to hold together the robots frame.
Step 3: Electronic Container and Gurney Deployment Mechanism
The electronic container and deployment mechanism are attached to the top platform with bolts. The electronic container will need several holes drilled for electronics. The deployment gurney will also be bolted down at the ends and secured to the container.
Step 4: Assembly of Deployment Mechanism
The Deployment Gurney Mechanism is made up of several components. 1 DC motor attached to an 18" x 1/4" thick screw moves a metal coupler up and down the 18" screw. The couple is attached to the 1/2" PVC pipe and connected to the 18" screw. The plastic PVC coupler is inter attached to the orange flexible pipe which in turn moves the gurney outward. Please note: 2 deployment mechanisms are needed in order to move the gurney outward.
Step 5: Electronics/Wiring
The AFM will be using the following electronic components.
(4) HB25 from parallex these are h-bridges to control the motors
(1) Sabertooth h-Bridge to control the deployment mechanism
(1) Arduino Micro controller.
The input pins for the HB 25 will be connected to pins 5, 9,10,11, these are PWM ports on the Arduino. The power pins on the HB 25s are connected to a power distribution bar and attached to the 5 volt and ground pins on the arduino. The Saber tooth controller will be connected to pins 4 & 5, which are PWM ports. The Pixy camera will connect to the ICSP port. The HB 25 and Saber tooth h-bridges will be connected to and on/off switch to protect the circuit. See picture above for full details of the power distribution.
Step 6: Code
When creating the code, I started by looking online to see examples of how the Pixy camera could be used. I found this project on Adafruit. By looking through the code on Adafruit, I learned about how the author used the position and size of an object detected by the camera. I adapted this code by changing how the motor is controlled and removing the pan/tilt sensor code. I first tested this using a smaller robot kit, which is pictured.
Step 7: Testing and Revisions to Code
After confirming that my code worked on a smaller robot, I changed the code to control the HB 25 motor controllers as if they were servos. The code required numerous revisions to work properly. One way of debugging the code was by printing values of variables to serial, which can be shown in a block comment at the end of my code (first picture). One major revision was to make the motors on one side go backwards, while the other goes forward, to turn properly (shown in second picture).
Step 8: Poster and Video
Here is a video of my prototype and the poster I used for my school's competition.