Introduction: Garage Stop Light

Are you tired of getting too close to the garage wall or afraid the garage door will hit your car?

No need to worry now with this handy little fix!

Step 1: Gather Materials

DISCLAIMER: not everything is shown in picture

LEDs (red and green)


Arduino Uno

Breadboard Jumper Wires

Small breadboard

Ultrasonic Sensor

Electrical Tape

Battery Pack (4 AAs)

USB type A to USB type B cable (printer cable typically)

Wood Sheet (used to make box)

Wire cutters


Electrical Conduit or PVC pipe


Step 2: Resistors for LEDS

Take two resistors, bend the wire on each side to use in the breadboard. Then shorten the ends but cutting them with the wire cutters. This will make your breadboard look neat and organized. Plug the resistor into the breadboard along a column. Each side should be in a different row. Take one of the jumper wires and plug it into one of the holes in the row at each end of the resistor. Do this for both resistors.

Step 3: LEDs

Take two LED ’ s (one red one green) and bend them at 90-degree angle. Then trim each on to fit into the wire harness better with the wire cutters again. Remember that the longer side is the positive side. The shorter end is connected to the negative wire.I represent the negative connections with a combination of black, gray and brown wires.

Step 4: Making a Bus

I created a connection for all the negative wires. This is called a bus, which is how to connect multiple wires to the same place. In figure 4, I have placed all the negative wires from the ultrasonic sensor and LED’s into a single row on the breadboard. There should be 4 wires connected.

Step 5: Ultrasonic Sensor

Figure 5 is the ultrasonic sensor and how the wires are connected to it. Notice the color of each wire to determine where the other end should be connected.

Step 6: Connect Outputs/Inputs

Next, connect the ultrasonic sensor and LEDs to the digital output side. I was using red wire for power, so to denote the red LED I used yellow wire. This yellow wire is coming from the resistor work we did early. The green wire is coming from the resistor connected to the green LED. The white and orange wires are coming from the ultrasonic sensor.

Step 7: Getting Power

Figure 7 is where the power and ground wires should be connected. The ground wire is coming from the connected grouping (bus) and the power wire is coming from the ultrasonic sensor.


Once everything has been connected it should look like figure 8.

DISCLAIMER: This picture was taken before I added in the breadboard for the resistors and negative wires. Reference the picture in step 2 for what the breadboard should look like.

Step 9: Connection to Computer

The next step is to use the USB cable (typically the one found from a printer) to plug into the computer.

Step 10: Get the Software

Go to the Arduino website and download the software for the Arduino for your OS.

Step 11: Get Our Code!

Copy and paste the text from into the Arduino window. Github is a great open source website to share code for DIY projects.

Step 12: Time to Upload

Click the upload button in Figure 10 and the system should be up and running!

BUT WAIT! There's more! IF you ever want to change the distance in which the green light comes on and when it switches to red, then all you have to do it change two simple numbers. Line 24 is when the red light comes on and 28 is when the green light comes on. These two numbers are in centimeters, so keep that in mind while measuring. Plug the Arduino back into the computer and hit upload again. Now you're ready to go!

Step 13: Making the Box

I used a 1/2 inch thick sheet of wood from the local hardware store. The dimensions I used to create the box were too small to fix all of the components. So I highly recommend that you place all the parts together and create accurate measurements. I cut out the sides, top, and bottom then cut the edges at 45-degree angle. This is to ensure the four pieces fit together nicely. For the front, I simply cut out another piece to entirely cover the front face. Then I glued together all the parts and used a pencil to mark out where the holes need to be drilled. Two holes need to be made on the front for the ultrasonic sensor and one more on the top for the wires going to the LEDs. It should look something like the last picture when completed.

Step 14: Placing the Components

Now it's time to fix the ultrasonic sensor and the LEDs. The first image shows how I used the two holes that were drilled in the front for the ultrasonic sensor. I decided to glue this as well so it would get consistent measurements. For the hole on the top of the box, I attached a 28-inch long piece of electrical conduit. You can also use PVC but this is what I had laying around. Once the pipe was glued to the box, I ran the wires for the LEDs all the way to the top. After making sure the LEDs were plugged in correctly, I drilled two small holes in the top of the conduit. With a small dap of glue in each hole, the next step was to poke the green LED through the bottom hole and the red through the top.

Step 15: Set It Up!

Place all of your components into your storage device. For this, I am just going to use the wood box and electrical conduit for the sensor and LEDs. I encourage you to use this part as a place to experiment with design. My solution for the housing of the components is not the most clever or appealing, so I implore you to try out your own design. Lastly, once everything is in place, put all the parks into the box and plug the battery pack into the Arduino.

Step 16: Mounting It to the Wall

This is also a step that can be higher user dependent. I chose to mount my garage stop light to the wall with velcro style command strips for very easy removal. This would be for changing the battery when needed. You can use any style of mounting that best suits your situation. When mounting to that wall, make sure the box with the ultrasonic sensor in it is at the level of your license plate. The pipe with the LEDs should be tall enough to that they are right in line with the driver's vision.

Step 17: Test It Out!

To make sure it works, compare it what we have!