Keep Truckin'

A long wood box has a truck in the middle and alphabet blocks nearby. When blocks are put onto the truck and a button on the side of the box is pressed, the truck drives forward or backward based on how heavy the blocks are.

This project almost broke me and might actually fuck me over for the rest of my life, since it coincides with both a very large project in my studio course and a very important interview timeline. It was a big lesson on hubris because I heavily underestimated how much work it would take to create a reliable mechanical device and overestimated my time and emotional bandwidth. But here we are. The device works reliably as of the day of presentation, with only a loose power cord that I need to fix before moving to next steps. I'll break down this project into a few parts: Design, making, and emotional turmoil.

The design of this project was probably the only part that didn't make me want to die. I made some super fun concept sketches at the beginning of this project that I intend on executing on for the final part of this project. But moreover, the general idea of mapping my mental load and calculating how each thing I need to do affects me mentally was incredibly fun before I had to actually make it.

The making part was the part I hated the most and suffered the most in. I'm not an engineer and while I think I have a good sense of craft and general making of things, I didn't have the time or patience that this project required. Ran into a lot of road blocks through just scheduling times to be in the wood shop, getting parts like load cells, and finding parts to connect my axel bits together. But the bigger problem was the amount of things I needed for this project. I needed one thing that was dependent on another thing and dependent on another, and that made planning super hard for me mentally. I couldn't fully test the belt until it was in the platform but in order to get the platform built I needed to cut the pieces but in order to cut the pieces Zach needs to let me into the woodshop and by the time I'd finally gotten Zach to let me into the woodshop it was Friday before the project was due. It's just hard to balance. I think I need to be more sure of myself and advocate earlier to get critical pieces in and ready, rather than kind of waiting because I feel like "final fabrication" should be done as close to the deadline as possible.

I guess the biggest thing was just that I didn't build a lot of tolerances into my schedule. Every problem I ran into added hours onto the long queue of tasks that I had to do each day, and also in turn added to my stress. I guess this project became a representation of the madness that its own creation caused. So it is. Things I've learned/would do differently: Make a solid plan to get parts together early. Test and link together early. Build modularly. Don't do mechanical shit ever again.

//Keep Truckin'

//Made by Caleb Sun

//This program takes weight information from a load cell
to drive a stepper motor to certain positions

#include <AccelStepper.h>

#include "HX711.h"

//pin mapping

//motor

const int dirPin = 12; 

const int stepPin = 13;

//button

#define butt 10

int readButt = 0;

//scale

#define LOADCELL_DOUT_PIN 3

#define LOADCELL_SCK_PIN 2

//util

#define motorInterfaceType 1

AccelStepper myStepper(motorInterfaceType, stepPin, dirPin);

int moveweight = 0;

int done = 1;

int inbound = 0;

int outbound = 0;

HX711 scale;

float calibration_factor = -7500;

int weight = 0;

void setup() {

 //motor setup

 myStepper.setMaxSpeed(1000);

 myStepper.setAcceleration(50);

 myStepper.setSpeed(200);

 //scale setup

 Serial.begin(9600);

 Serial.println("HX711 scale demo");

 scale.begin(LOADCELL_DOUT_PIN, LOADCELL_SCK_PIN);

 scale.set_scale(calibration_factor); //This value is obtained by using the SparkFun_HX711_Calibration sketch

 scale.tare(); //Assuming there is no weight on the scale at start up, reset the scale to 0

 //button setup

 pinMode(butt,INPUT);

}

void loop() {

 readButt=digitalRead(butt);

 //if button is pressed, read scale and map weight to position

 if (readButt == 1){

   weight = scale.get_units();

   moveweight = map(weight, -14  , 0, 2000, -2000);

   if(moveweight >2000){

     moveweight=2000;

   }

   if(moveweight<-2000){

     moveweight=-2000;

   }

   delay(1000);

   outbound = 1;

   inbound = 1;

 }

 //drives truck to mapped distance

 if(outbound == 1){

   myStepper.moveTo(moveweight);

   while (myStepper.distanceToGo()!=0){

       myStepper.run();

     }

   if (myStepper.distanceToGo() == 0){

     inbound = 0;

   }

 }

//drives truck to original position

 if (inbound == 0){

   delay(2000);

   myStepper.moveTo(0);

   outbound = 0;

   while (myStepper.distanceToGo()!=0){

       myStepper.run();

     }

   if (myStepper.distanceToGo() == 0){

     myStepper.stop();;

   }

 }

}