Ultrasonic Rangefinder
In this step we will install the Ultrasonic Rangefinder.
Note: For Spirit builds without the pan / tilt head, it is possible to attach the ultrasonic rangefinder to the front of Spirit's main frame. Instructions for this configuration will be provided in a separate section under Alternate Configurations.
Required Parts:
4x M1.4 5mm Screws (these are very slightly shorter than the other small screws used in other steps)
4x M1.4 ('small') Nuts
4x Small Metal Washers
1x Pan Head Upper Metal Frame
1x Ultrasonic Rangefinder
1x Eyes LED Circuit Board
1x Long Cable approx 6" / 150mm length
Two Options for Ultrasonic Rangefinder:
When connecting the ultrasonic rangefinder, you have two options. The rangefinders ship with the connecting pins pointing outward, as shown in the picture above. These pins go on the top side of the head. You can choose to mount this one of the following ways:
You can leave the pins as they are. This will work fine, except the connecting cable will extend upward off the top of the head. This may not look as "clean" as the second option.
The other option is to bend the connecting pins downward, so the cable connects from the bottom. This results in a more clean look, but you do need to take care when bending the pins. There is some risk of damage involved in doing this. If done carefully it should work okay.
We will follow the second option in our instructions below.
If you choose to follow the second option, use a set of thin pliers to very carefully bend the pins so they poke straight off the circuit board. Be careful to not damage parts on the board when doing this. I find it works best to pinch the pins right at the bend. By pinching at this point, it will help to straighten out the pins without adding as much additional stress to the metal. You want to be careful to not break the pins.
To complete the bend, press the pins down on a flat surface and gently rock the rangefinder down on top of the pins. This will cause the pins to fold up behind the rangefinder.
The board should look like this after the bend is completed.
Feed the cable for the ultrasonic through the opening in the metal frame.
Connect the cable to the pins on the rangefinder. Connect the blue wire to the pin labeled "Vcc".
VERY IMPORTANT WARNING:
Carefully check the direction the cable is connected. The blue wire needs to connect to the pin labeled "Vcc". This is printed on the blue circuit board. If you connect this cable backward, things may be damaged when powering up the robot.
Connect the ultrasonic to the metal frame as indicated in the pictures above. The thin metal washers should be used on the front side in front of the metal frame.
IMPORTANT NOTE:
Be sure the ultrasonic slides in BEHIND the front of the metal frame. Study this carefully in the images above.
Next, connect the cable to the connector on the LED circuit board. Feed this cable through the same opening used for the ultrasonic cable.
IMPORTANT NOTES:
Take note the direction of the LED circuit board in the image above. The LEDs should be along the front edge of the board.
Again, double check that the cable for the LED board goes through the opening on the metal frame.
Attach the LED board to the metal frame as shown above.
IMPORTANT NOTES:
It is suggested to use a thin screwdriver for this step. Be careful when using the screwdriver to avoid too much pressure on the sides of the metal openings on the ultrasonic. They are thin walls and can bend easily. This won't damage operation but will leave a visible dent.
Alternately, you may prefer to install the screws from the bottom. If you choose to do this, leave the thin metal washer on the top still to prevent the screw backing out through the LED circuit board. This method may be easier but the completed finish isn't as clean as the nut will be visible on the top. Either method will work fine.
The completed head assembly should look like the image above.
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