(2D) Collectible Objects using Raycasts

Hello fellow Unity users. :)

I've completed the excellent series of tutorials here (https://www.youtube.com/playlist?list=PLFt_AvWsXl0f0hqURlhyIoAabKPgRsqjz) and I'd like to add 'collectible' items to my prototype game.

This tutorial series develops a 2D platformer, whereby all collisions are worked out using raycasting (as opposed to rigid bodies / colliders). It works fine, but I'm not sure how to proceed so as when my player (a simple quad, currently) collides with another quad (tagged as 'Pickup') the other object is destroyed.

I tried this via the usual method of adding rigid bodies / box colliders and checking onTriggerEnter2D (after setting the relevant setting of 'Is Trigger?' to yes. But the event doesn't ever appear to fire.

 (Code Below: Controller2D)
 using UnityEngine;
 using System.Collections;
 
 [RequireComponent (typeof (BoxCollider2D))]
 public class Controller2D : MonoBehaviour {
 
     public LayerMask collisionMask;
     
     const float skinwidth = .015f; 
     public int horizontalRayCount = 4;
     public int verticalRayCount = 4;
 
     float horizontalRaySpacing;
     float verticalRaySpacing;
 
 
     BoxCollider2D coll;
     RaycastOrigins raycastOrigins;
 
     void Start () {
         coll = GetComponent<BoxCollider2D>();
         calculateRaySpacing();
     }
     
     public void Move(Vector3 velocity){
         UpdateRaycastOrigins();
         if (velocity.x != 0){
             HorizontalCollisions(ref velocity);
         }
         if (velocity.y !=0){
             VerticalCollisions(ref velocity);
         }
         transform.Translate(velocity);
     }
 
     void HorizontalCollisions(ref Vector3 velocity){
         float directionX = Mathf.Sign (velocity.x);
         float rayLength = Mathf.Abs(velocity.x) + skinwidth;
         
         for (int i = 0; i < horizontalRayCount; i++) {
             Vector2 rayOrigin = (directionX == -1)?raycastOrigins.bottomLeft:raycastOrigins.bottomRight;
             rayOrigin += Vector2.up * (horizontalRaySpacing * i);
             RaycastHit2D hit = Physics2D.Raycast(rayOrigin,Vector2.right * directionX,rayLength,collisionMask);
 
             Debug.DrawRay(rayOrigin, Vector2.right * directionX * rayLength,Color.red);
 
             if (hit) {
                 velocity.x = (hit.distance - skinwidth) * directionX;
                 rayLength = hit.distance;
             }
         }
     }
 
     void VerticalCollisions(ref Vector3 velocity){
         float directionY = Mathf.Sign (velocity.y);
         float rayLength = Mathf.Abs(velocity.y) + skinwidth;
 
         for (int i = 0; i < verticalRayCount; i++) {
             Vector2 rayOrigin = (directionY == -1)?raycastOrigins.bottomLeft:raycastOrigins.topLeft;
             rayOrigin += Vector2.right * (verticalRaySpacing * i + velocity.x);
             RaycastHit2D hit = Physics2D.Raycast(rayOrigin,Vector2.up * directionY,rayLength,collisionMask);
             Debug.DrawRay(rayOrigin, Vector2.up * directionY * rayLength,Color.red);
 
             if (hit) {
                 velocity.y = (hit.distance - skinwidth) * directionY;
                 rayLength = hit.distance;
             }
         }
     }
 
     void UpdateRaycastOrigins(){
         Bounds bounds = coll.bounds;
         bounds.Expand(skinwidth * -2);
 
         raycastOrigins.bottomLeft = new Vector2(bounds.min.x,bounds.min.y);
         raycastOrigins.bottomRight = new Vector2(bounds.max.x,bounds.min.y);
         raycastOrigins.topLeft = new Vector2(bounds.min.x,bounds.max.y);
         raycastOrigins.topRight = new Vector2(bounds.max.x,bounds.max.y);
 
     }
     void calculateRaySpacing(){
         Bounds bounds = coll.bounds;
         bounds.Expand(skinwidth * -2);
 
         horizontalRayCount = Mathf.Clamp(horizontalRayCount,2,int.MaxValue);
         verticalRayCount = Mathf.Clamp(verticalRayCount,2,int.MaxValue);
 
         horizontalRaySpacing = bounds.size.y / (horizontalRayCount - 1);
         verticalRaySpacing = bounds.size.x / (verticalRayCount - 1);
     }
 
 
     struct RaycastOrigins {
         public Vector2 topLeft,topRight;
         public Vector2 bottomLeft,bottomRight;
     }
 
 }
 
 
 (Code Below: Player)
 using UnityEngine;
 using System.Collections;
 
 [RequireComponent (typeof (Controller2D))]
 
 public class Player : MonoBehaviour {
 
     float moveSpeed = 6;
     float gravity = -20;
     Vector3 velocity;
 
     Controller2D controller;    
 
     void Start(){
         controller = GetComponent<Controller2D>();
     }
 
     void Update(){
 
         Vector2 input = new Vector2(Input.GetAxisRaw("Horizontal"),Input.GetAxisRaw("Vertical"));
 
 
         velocity.x = input.x * moveSpeed;
         velocity.y += gravity * Time.deltaTime;
         controller.Move(velocity * Time.deltaTime);
     }
 }

Could anyone kindly point me in the right direction and advise as to what I would need to consider when trying to make my player collect an item?

My first request on here, so hopefully I've done everything within the guidelines. :)