Moving to a Target Distance

Now that you have created the constant variables needed to calculate the amount of ticks per mm moved, you can use this to set a target distance. For instance, if you would like to have the robot move forward two feet, converting from feet to millimeters and multiplying by the COUNTS_PER_MM will give you the amount of counts (or ticks) needed to reach that distance!

Let's create two more variables called leftTarget and rightTarget. Add the and blocks within the if/then statement that will run once Play is selected.

Inserting our leftTarget and rightTarget variables

Converting from mm to Feet

Right now the main distance factor is COUNTS_PER_MM , however you may want to go a distance that is in the imperial system, such as 2 feet (or 24 inches). The target distance in this case will need to be converted to mm.

To convert from feet to millimeters use the following formula:

$$d_{(mm)} = d_{(ft)} × 304.8$$

If you convert 2 feet to millimeters, it comes out the be 609.6 millimeters. For the purpose of this guide, lets go ahead an round this to be 610 millimeters.

Converting Feet to Ticks

Next, multiply 610 millimeters by the COUNTS_PER_MM variable to get the number of ticks needed to move the robot 2 feet. Since the intent is to have the robot move in a straight line, set both the leftTarget and rightTarget, to be equal to 610 * COUNTS_PER_MM

Lastly, we need to change the so that both motors are set to the appropriate target position. To do this add the and blocks to their respective motor.

All of the blocks added to set a target distance