Introduction: Jumbo-Sized Telescoping Light Painter Made From EMT (Electrical) Conduit
Light painting (light writing) photography is performed by taking a long-exposure photograph, holding the camera still and moving a light source while the camera aperture is open. When the aperture closes, the trails of light will appear to be frozen in the photograph! This can be used to create all kinds of unique photo effects, write text, and draw 2D or 3D objects!
Electrical (EMT) conduit can be outfitted with some simple electronics and a red-green-blue (RGB) light-emitting diode (LED) in order to create colorful paintings of light, for which the EMT conduit will serve as a low-cost telescoping pole. Two Cinch telescoping couplings from Elation Sports Technologies are used to connect three 5-foot long pieces of EMT conduit of sizes 1/2", 3/4", and 1". This creates a jumbo-sized multi-colored light writing tool with a fully-extended length of nearly 15 feet!
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3. 1 x 5-ft length of 1/2" EMT conduit
4. 1 x 5-ft length of 3/4" EMT conduit
5. 1 x 5-ft length of 1" EMT conduit
6. 3D-printed 5mm RGB LED cap
7. Various electronic components as listed in the other step of this article, including an Arduino Nano clone microcontroller board
8. Four colors of 28 gauge solid core wire, cut to length as needed for your telescoping pole (15 feet in this article)
12. Wire connector pin crimping tool (we used this IWISS crimping tool from Amazon.)
13. PC, USB-mini cable and Arduino IDE software to program the Arduino Nano
14. Battery bank or other power supply for the Arduino Nano
15. You will need a camera with long exposure photography capability to take the light painting pictures (we used the Sony Cyber-Shot DSC H300, which can take long exposure shots up to 30 seconds long)
14. (Optional) Zip ties to secure the wires leading to the RGB LED
15. (Optional) Hot glue gun
Step 1: Electronics
Construct your circuit following the schematic image.
The circuit works as follows:
1. One RGB LED (which is actually three LEDS in one package) is sufficient to create all the colors of the rainbow, from combinations of its red, green, and blue components.
2. When pressed, the pushbutton powers the LEDs according to which of the three switches are enabled. Note we used a normally-open (i.e. normally-off) pushbutton. In contrast, a normally-closed pushbutton would mean that the circuit is active (and the LED shines) while we aren't pressing the button.
3. The Arduino Nano can be programmed to set specific colors by sending pulse width modulation (PWM) signals to the red, green, and blue LEDs. Note that only certain pins are capable of hardware-driven PWM on the Arduino Nano. Software-driven PWM is still an option on the other digital I/O pins. For this example, we used pins 3, 5, and 6.
4. The smooth rainbow effect achieved in the final photographs is achieved using the Arduino code which is linked in the next step of the this tutorial.
The 2x15 pin 0.1" spacing female headers are included so that the Arduino Nano can be replaced in case it gets damaged or otherwise breaks.
The RGB LED must also be wired. Solder 4 x 28 gauge solid core wires to each of the four pins of the RGB LED. We used a common-cathode LED for this example, meaning that the ground pin is common to all three colors (red, green, and blue.) In contrast, a common-anode RGB LED would have just one positive voltage pin powering the red, green, and blue LEDs. We used clear/transparent heat shrink to prevent the LED wires from shorting one another close to the LED package, and also used colored (red, black, white, yellow) heat shrink to insulate and strengthen the wire connections.
To create the cables needed for this project, we used a IWISS crimping tool (see the Supplies section for a purchase link) plus the following components:
There are multiple cable crimping tutorials online, but, like soldering, the best way to learn how to crimp cables is just to practice doing it.
Programming the Arduino is done by connecting it to a PC with a mini-USB cable. Open the Arduino integrated development environment (IDE) software to flash your desired code to the Arduino. The code for this project can be found at this link on Github!
With the electronics completed, we are ready for assembly!
Step 2: Hardware Assembly
First, we created our telescoping pole from EMT conduit using 2 x Cinch telescoping couplings from Elation Sports Technologies, and three 5-foot pieces of 1/2", 3/4", and 1" EMT conduit.
We used two 3D printed parts to attach the circuit board and the RGB LED to our EMT conduit telescoping pole.
We used a custom 3D-printed cap to mount the LED and its holder, plus 2 x #10-32 x 3/4" long machine screws and nuts to attach the cap to the end of our 1/2" EMT conduit. The 5mm (T1-3/4) LED holder we used is linked here.
Insert the wired RGB LED through the 3D-printed cap and then install it into its holder. Push the LED + holder into the cap, and then bend the RGB LED's leads/wires so that they stick out through the slot in the cap as shown. Now the cap can be attached to the 1/2" EMT conduit.
Another custom 3D-printed mount was used to attach the circuit board to the 1" EMT conduit near the base of the telescoping pole, again with 2 x #10-32 x 3/4" long machine screws and nuts. The circuit board was attached to its mount using 4 x M2 x 6mm long machine screws and nuts.
To power the assembly, we used a portable battery bank with a mini-USB cable plugged into the Arduino Nano.
Step 3: Camera Settings
To create long-exposure photographs, you will need a camera with this feature. We used the Sony Cyber-Shot DSC-H300 camera listed in the Supplies section, above. To take a long-exposure photograph, set the camera to manual mode by turning the top wheel to the M setting. Press the center circle button near the screen to open the options menu. Use the four buttons around that center circle button to set the ISO (dependent on the lighting situation) and duration of the photograph (a maximum of 30 seconds.) You might need to play with these settings until your photographs come out the way you want!
With your camera prepared and your telescoping light painting assembly complete, you are now ready to create your own light paintings!
Step 4: Results
Here are some of our creations using our telescoping light painting pole created using EMT conduit telescoping couplings from Elation Sports Technologies. These paintings have a maximum height and width of almost 15 feet! For these photos, we used the smooth rainbow color feature which was set using the Arduino Nano's hardware PWM capability.
Check out our other Instructables articles:
- Accuracy-Sensing Sports Rebounder with ESP32
- EMT Conduit-Mounted Weather Station Wind Sensors
- Telescoping EMT Conduit Pole Extension Sensing Methods + Photoresistor Implementation
- Force-Sensing Telescoping EMT Conduit Pole
- Homemade/DIY Telescoping Pole From EMT (Electrical) Conduit
Our website's blog posts offer more inspiration for your next EMT conduit project!
- Telescoping EMT Conduit: A Technical Guide
- Five Electrical Metallic Tubing (EMT) Conduit Telescoping Pole Ideas to Boost Your Creativity
Austin Allen is the Founder and Owner at Elation Sports Technologies LLC, which specializes in the development of novel sports and recreational products.