Motorised Route Roller

A project I have been working on lately is motorising a ‘route roller’, which is a device which allows you to carry and view an A4 route sheet when on your classic motorcycle. Here is the image of the version sold by the VMCC:

I found the device a little clumsy to use, because you often have to let go of the handlebar and direct your attention to twiddling the knob at the side to scroll the map. I figured that there had to be a better way which would be quicker and would be less distracting, so decided to motorise one.

The idea was to build an extension to the existing route roller so that you could just add the motor unit with little modification. This first version uses two laser cut brackets from 3mm acrylic, two 3D printed plugs that fit into the end of the rollers and hold the two axles, three 3D printed spur gears, and a 3D printed cover. The unit is driven by a cheap stepper motor controlled by an ATTiny microcontroller and a ULN2003 darlington array.

Here are some photos of the unit:

Here’s a (pretty crappy) video of the unit working:

I’ll make the plans and circuit available on this blog when I have perfected the device a bit more and given it a good road test. But if you are interested in making one for yourself and trying it out, then email me and I can send you the necessary details.

Here is the Fritzing circuit for the motorized route map:

I used an ATTiny 85 microcontroller to send the signals from the switches to the ULN2003A (Darlington array) not because it was easier than creating a simple transistor circuit (it wasn’t) but because I have a box full of them, and they need using! Anyway, it’s kinda nice to use an ATTiny, as it opens up possibilities for mods later on (e.g. tap/hold the buttons to change speed).

The components needed for this crude (but simple design) are:

2 x 12mm push buttons

1 x ATTiny85 Microcontroller

2 x 10uF caps (for power supply – a bit overkill)

1 x 5V voltage regulator (to power the ATTiny)

2 x 10K resistors, 1/4 W

1 x ULN2003A Darlington array

12V stepper motor

Wire of various colours.

Stripboard

Note: the stripboard shown in the Fritzing circuit is just for illustrating the circuit, I actually used less than half of the full 9 x 25 board so that it would fit in the small space available.

The stepper motor I originally used was a cheapo 5V (and the one that you can see working in the video) but it was very underpowered and would regularly jam and stop working. So I upgraded it to a cheapo 12V, which was slightly better, but not perfect. See below:

The ATTiny was programmed using an Arduino Uno as a programmer. The Arduino code for the ATTiny is here:

/*
* 
* IN1 = pin 2
* IN2 = pin 3
* IN3 = pin 4
* IN4 = pin 5
* 
*/


#include <Stepper.h>

/*-----( Declare Constants, Pin Numbers )-----*/
//---( Number of steps per revolution of INTERNAL motor in 4-step mode )---
#define STEPS_PER_MOTOR_REVOLUTION 32

//---( Steps per OUTPUT SHAFT of gear reduction )---
#define STEPS_PER_OUTPUT_REVOLUTION 32 * 128 //2048

// Button for scrolling up and down
#define UPBTN 1
#define DOWNBTN 5

//The pin connections need to be 4 pins connected
// to Motor Driver In1, In2, In3, In4 and then the pins entered
// here in the sequence 1-3-2-4 for proper sequencing
Stepper small_stepper(STEPS_PER_MOTOR_REVOLUTION, 2, 3, 4, 0);

int Steps2Take;

void setup() {
  pinMode(UPBTN, INPUT);
  pinMode(DOWNBTN, INPUT);
  small_stepper.setSpeed(700);
}

void loop() {

  // Get thevalue form the up button
  int up = digitalRead(UPBTN);
  int down = digitalRead(DOWNBTN);

  if (up == 1 && down == 0) {
    small_stepper.step(STEPS_PER_MOTOR_REVOLUTION);
  }

  if (down == 1 && up == 0){
    small_stepper.step(-STEPS_PER_MOTOR_REVOLUTION);
  }

}

I will have a look around for the mechanical drawings. I have done many different designs, using lots of different stepper motors and plain electric motors, so will take a bit of time to locate the one above. I upgraded the design later on to use a plain geared 12V electric motor, as it was more powerful and simpler to design.