Introduction: Instructable Robot Speaker at Pier 9
This 2m tall Instructable robot is a powered speaker sculpture with movable parts. I was very fortunate to be commissioned to create this sculpture for Pier 9 workshop. During my residency, I learned to operate laser cutter, industrial 3d printer, manual lathe, woodshop machineries, etc. I applied most of the technology to this sculpture.
A big thanks to Noah and Vanessa and shopstaff at Pier 9 for helping me with the build
Step 1: Design the Robot
I started looking for reference of the robot logo, it turns out there is no image of this robot from a different angle, therefore I have to come up with the side view. I also added some details, the body is more dynamic and feet are converted to tracks looking shape. I designed the model in 3ds max, the two eyes on the robot are tweeters, the 3 holes in the middle are mid-range speakers, the port at as speaker enclosure vent. the subwoofer is hidden above the legs. The plan is to construct the robot body shell with lightweight polymer material and the speaker core with MDF and wood structure. to make the speaker reproducing accurate sounds, I also eliminate many movable parts and avoiding using screws that can be seen from outside. the only movable parts are the 3d printed hands. The next step is break down the 3d model into 2d patterns.
Step 2: Make the 3d Model Patterns
I have used this technique on many of my sculptures. before I had access to laser cutter, I used to print letter size cardstock by stacks then painstakingly cut the pattern and score the fold lines. the whole process could take me days. Now with the aid of laser cutter, I can separate models to bigger patterns, the laser cutting bed is measured 24X 36in. After experiment with different kind of paper, I found a of white colorstock with the right thickness and good surface finish.
the process is to Import the 3d model to Pepakura，use pepakura to unfold and separate model to paper patterns. Once arranged to pattern to fit the cutting bed. export it to DXF then open in illustrator, assign cutting line and folding line to different laser setting. I used 8-10% power to cut , 2% to etch. first etch the folding lines, without moving the paper, run another path to cut the cutting lines. Once everything is nicely cut, carefully collect the paper , and start to glue them together.
Step 3: Construct the Body Shell
Sort of piles of parts, then carefully glue them together. I used contact cement for this application.
Step 4: Design the Internal Structure
Step 5: Assemble Robot Feet
To make the tracks on robot feet appealing. I applied kerf cutting technique to cut plywood. First of, water jet 1/2in plywood to make the base structure, Then I used laser cutter to cut 1/4in plywood, the kerf cutting technique was posted by former artist in residence Aaron Porterfield.
1/4in plywood is cut to wide stripes, then wrap around the curved edge of the base structure. the result it's a smooth curved surface with track marks. I sanded around the edges and it is ready to be painted.
Step 6: Reinforce Body Shell With Composite Materials
I used fiberglass mesh and e glass to reinforce on the inside of the body shell. The resin I used is a blend of epoxy resin with strained fiber, marble powder, graphite and dye pigment, the mixture has a honey consistency and good self leveling. the area brushed on with resin mixture will turn translucent with a red tint， this way it is easier for me to see if there is weak spot or area i missed to apply mixture. I let the resin fully cure for 1 week in the spray booth, then lightly sand the outside to get rid off join seams.
Step 7: Fabricate Small Parts
The antenna of the robot is lathed on the wood lathe, buffed with wood dust, the rings on the eyes are laser cut then formed with a table router.
Step 8: Prime and Paint
Due to many chemical restriction on the Pier, I decided to paint the robot with water based , less toxic paint. All the paints are first lightly sanded with 220 grit. I used a roller to apply 3 coats of primer. then follow by 4 coats of base color, finished with 3 coats of water based polyurethane. the finish is vibrant yellow with satin finish.
Step 9: Assemble the Electronic Component
The core of this sculpture is the speaker enclosure. the box is made of MDF, a common material to build DIY speaker box. The volume of the box is measured to suit the factory recommend volume for the speaker. the Middle 10 in woofer has a much larger box because it is a vented system. the two smaller 8in speaker has a closed box of 0.11 cubic ft. The cross over is a 3-way 300watts Dayton Crossover. the back of the robot is equipped with 250watts Dayton full range plate amplifer.
Step 10: 3d Printing Robot Hands
the only movable parts on this robot sculpture are the hands. there is little detail of the hands from the logo, so this is my interpretation of what it is suppose to look like in life. I got the reference from Baymax's balloon hands. all the joints are movable. the size of the hands are quite large for a desktop printer, so with the help of 3d print shop lead Gabe i printed them in Stratasys fortus 450m. The material hands are printed with is stratasys ultem 9085
Step 11: Complete
After the hands are installed, this sculpture is complete! the robot is standing on two trays to be moved around. plug into the amplifier and then test to sound of the speakers. The sound reproduction is decent and the volume is loud enough to be used outdoor as a PA speaker.