Introduction: DIY Phone Trigger Buttons (PUBG/ ROS/ Fornite)

3D print some Trigger Buttons for your phone! Play FPS shooter games & Battle Royale games like a pro on the go! Works really well with Fortnite Mobile, Rules of Survival & Knives Out and especially PUBG Mobile!

It simply clips and slides on the edge of your phone and instantly gives you that classic PSP Style L&R buttons!

Watch The Full Video Tutorial:

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Step 1: How It Works

I made this project for the Stick It! Contest here at instructables. So how does this project fit in? Well first the whole project heavily relies on Aluminum Tape! Not to mention that double sided padding also plays a huge role here.The 3D printed parts were just made to make the project look and feel more professional.

What's With The Aluminum Tape?

I recently discovered that Aluminum Tape actually existed. They can easily be found in your local hardware store in the roofing section. Apparently they relatively cheap and are really good conductive adhesives. Aluminum tape has a variety of uses, from housing repairs to doing minor repairs on aircraft and racecars!

Today I gave another use for it and it's by using it for capacitive touch conduction! I recently found out that you can use foil or aluminum tape on a phone screen to trigger it from a tiny distance. When you stick aluminum tape on a screen and touch it with your fingers on the other end, your phone still interpret it as a touch.

How Touchscreens Work: Here's a video explaining how touchscreens work. The whole project revolves around the capacitive touch concept.

This pretty much explains why the foil experiment worked. It's simply because most phones today have capacitive touchscreen panels. It detects a touch through a change in capacitance. In physics capacitance is defined as 'energy stored in electrostatic force' (ex: two metal plates with an insulator in between). Putting a foil on a screen only creates a tiny change in capacitance, but holding it with your fingertips would create a larger change. Just add a lever switch mechanism and you have a DIY Phone Trigger Button!

Step 2: My Simple Design

The Problem:

Ever experienced playing an open world shooting game on your phone? If you did, you must have hated the touchscreen experience. It's pretty hard having no phyiscal buttons to press, unlike the classic PSP.

My Design:

I tried to think of a simple but effective mechanism for my project design. I started to write it on a piece of paper the moment I figured it out. I didn't make it look good since I was going to 3D model it in a software anyways.

The Mechanism:

  1. The Lever - It is a conductive piece that touches your finger. Its conductivity is isolated from the clip.
  2. The Clip - On the other hand, the clip has a conductive pathway leading to contact point. The contact point is the area that touches your phones screen.
  3. The Pin - There is a pin that holds the lever and clip together.
  4. The Spring - I added a non conductive spring in the design. It goes in between the lever and the clip. It helps the lever go back to its original position when it isn't pressed.
  5. The Switch - The whole this basically is an open switch. My first design included a tact switch or a mechanical switch but I figured it would make the project much more complicated so I came up with the open lever design.

Mechanical States of the Mechanism:

  1. When Pressed Down - When the Phone Trigger is pressed down, your fingertips conducts with the lever. At this state the lever arm touches its conductive bottom (lump) with the clip's conductive surface. The clip has a conductive pathway leading to the contact point (metal plate touching the phone's touchscreen). Your phone then senses this as a 'tap'. The spring creates pressure to bring back the lever arm to its original position when pressure isn't applied.
  2. When Not Pressed - When pressure isn't applied to the lever arm, the conductive pathway isn't complete. Nothing will happen and your phone wont sense a touch even if your fingertips are touching the lever.

Step 3: Things You'll Need


  • Roll of Aluminum Duct Tape
  • Roll of Double Sided Padding Tape

Homebrew 3D Printed Parts:

  • 3D Printed R1 Clip
  • 3D Printed R1 Clip
  • 3D Printed Lever (2x)

Hardware Parts:

  • Metal Rivets (2x)
  • Heatshrink Tubing (2x)

Tools & Equiptment:

  • 3D Printer
  • 3D Printer Filament (ABS or PLA)
  • A Pair of Pliers
  • A Pair of Scissors
  • Kitchen Lighter
  • Cutting Knife
  • Metal File
  • 400 Grit Sandpaper

Step 4: Download the 3D Printing Files

3D Modelling The Project:

I applied what I've learned from the university and used Solidworks to design my plastic components. Did a lot of manual sketches before I 3D modeled it in the computer. I used a digital caliper to input the measurements. The whole design was based from my Galaxy S8, it was a decent choice since most phones today have almost the same thickness with it. Some of my designs failed, some were unstable but this was my most reliable and simplest lever action design among the six I did. The files are in the links below if you guys want to print your own or if you want to tweak and modify it.

3D Printing Files

The files can be downloaded from the links below. For those who are new to 3D Printing, download the STL files. STL is the commonly used 3D model file that most slicing softwares can read. If you want to modify my design, you can download the Solidworks files.

STL File Package: Click To Download

Solidworks Raw File: Click To Download

My 3D Printer Settings:

  • Layer Height (0.2mm)
  • Shell Thickness (1.6mm)
  • Fill Density (100%)
  • Print Speed (50mm/s)
  • Nozzle Temp (223°C - For ABS Filament)
  • Heat Bed Temp (103°C)
  • Support Type (None)
  • Platform Adhesion Type (None)

Step 5: Print the Plastic Parts

This is a 3D Printed version of my Capacitive Phone Trigger project. I'm also working on a non 3D printed version for those who doesn't have access to a 3D printer.

In 3D printing the parts, if you want to get good quality, I would recommend printing them one by one. It's faster when you print them as a set, like what I did here, but you're going to sacrifice a little bit of print quality. Overall, the printed set took me around 30 minutes to finish.

Step 6: Need a Good 3D Printer for Cheap?

I won an SLA 3D printer from the Full Spectrum contest here at ibles but the SLA resin was too expensive for casual prints. I use it often but I try to conserve much resin as I can. The print resolution was exceptionally smooth. I decided to keep it since SLA resin would someday become cheaper when SLA printers would become more common.

My First FDM 3D Printer (ANET A6):

A year ago, I was looking for an affordable FDM 3D printer with a reasonably big print size of 210x210x270 or above. Luckily introduced me to their website and I found this, a very decent 3D Printer kit under $180. Eventually we've made several collabs and they eventually gave me this for free. I've been using this FDM 3D printer for almost a year now and so far I'm enjoying it. Haven't gotten problems with it so far. My favorite part was the assembly. It came as a kit so I had to assemble it from scratch. It was a real learning experience! I got to familiarize myself with the working principles of an FDM 3D printer. Surprisingly the box included evrything I needed (literally EVERYTHING). To my surprise, it came with some Tools, a 16GB SD Card, a Card Reader and a 1KG Spool of PLA Filament! It really was the perfect 3D printer that got me into 3D printing. I can recommend this to experienced makers who want to get into 3D printing.

You can buy from this link to get a 20% discount:

They're having a Mid Year Sale this June 17th! If you're interested in getting up to 50% off in buying a 3D printer. You could visit the link below:

Step 7: Sand & Clean the Plastics

One of the distinct qualities of a 3D printed part is the layered lines. I chose to sand it to remove those lines so that the plastic would feel much smoother to the hand. Use a sheet of 400 grit sandpaper to smoothen the plastics. For the hard to reach areas, use your metal file.

There's also a better way to do this, it's called the "Acetone Vapor Method". The output would look as if the parts were injection molded. To see more, here's a tutorial done by "DIY Perks" on the Acetone Vapor Curing.

Step 8: Drilling the Lever Holes

The lever should move freely on the pin. If your rivet's pin has a larger diameter than the hole of your 3D printed lever pat, make sure to drill a larger hole through it so it could move freely.

Step 9: Cut a Strip of Aluminum Tape

Using your cutter and ruler, cut a strip of aluminum from your roll of aluminum tape. I'm showing this step to make the next steps of this tutorial clear.

Step 10: Wrapping Aluminum Around the Lever

The aluminum tape is like a sticker. Peel of the plastic to reveal the adhesive and wrap the aluminum strip around the lever. The aluminum tape here is used to conduct with your fingers.

Step 11: Let's Make Some Improvised Lever Springs

Making springs is really tedious, finding one that fits the project would even be more difficult. To save you some time, I have deviced I way to make springs out of the stuff you already have. It turns out staking those double sided padding tapes makes a really good spring! But be sure to get the spongy ones since the Red 3M automotive tape is too rigid.

Cut four squares of double sided padding tape and stack around 4-5 of them on top of each other, then cut it down to smaller strips. Using your tweezers, put your improvised springs at the bottom of your lever (between the two lumps/ curves).

Step 12: Sticking a Conductive Sheet to the Contact Point

  1. Stack two layers of double-sided padding tape and cut it down into a tiny little square.
  2. Use your tweezers and stick it at the very tip of the slimmer pillar.
  3. Cut down a thinner sheet of aluminum tape (1mm of width or less). The thinner the better! If you make it too wide, your phone could have trouble sensing your touches since a wider strip could cause an interference.
  4. Peel the plastic of the aluminum tape.
  5. Stick the thin strip of aluminum tape from the bottom part of the clip, to the pillar, up to the squishy spongy tape you added from step 2.
  6. Cut the excess strip using a cutter knife.

Step 13: The Contact Point

Cut a large square piece of aluminum tape and stick it on top of the aluminum strip that lies above the sponge. This part is where the your touch from the lever gets translated into touches on your screen. It must be considerably large in order for your phone to pick up a change of capacitance when your finger and lever touches the conductive path.

Step 14: Wrap Aluminum Around the Clip

Wrap aluminum around the base. This is done to continue the conductive path from the contact point to the lever.

Step 15: Adding Some Padding

Cut two rectangular pieces of double-sided padding tapes.

Beneath The Clip:

Put one beneath the clip, this one is really important. There are phone with metallic edges like iPhone 6/7/8/X and Samsung Galaxy S8/S9. The foil running underneath the clips must not touch the phone's edge, otherwise it would just trigger the touchscreen. To isolate this, use a thick pad of your double-sided padding tape.

The Pillar:

Another pad of double-sided padding tape must be added to the wider pillar. I did this so that project would fit snugly once you have clipped it to your phone.

Step 16: Using Some Heatshrink Tubing

I added heatshrink to protect the contact point (aluminum foil of the tips) so that it wouldn't get torn or creased when you're clipping the Trigger Project to your phone. It also prevents your screen from getting scratched by the aluminum. And yes, no matter how thin an soft aluminum is, it can scratch your screen without having rubber (heatshrink) on top of it.

Heat-shrink tubing is non-conductive so how exactly do you actuate the capacitive cells on the screen through it in your video?

In engineering physics, capacitance can occur when there are two conductive elements between an insulator. By definition, capacitance is the ability to store energy in an electrostatic field. This means your phone's 'capacitive' screen would still be able to pick up the changes in capacitance, thus interpreting it as your finger taps.

Step 17: Making Pins Out of Rivets

Grab your rivets and use a pair of pliers to snip them into segments (1.4mm long).

During My Designing Stage:

When I was in the process of designing the project's prototype, I used chicken wire as my pins but they turned out to be too soft (they bent too much). I found a way around this and it's by snipping a portion of the Rivet. Rivets have pins that are really strong and rigid, making it as an ideal source of pins for the lever mechanism.

Step 18: Inserting the Pin

After assembling all the other components, it's now time to put them together. Grab the lever and carefully align it to the clip. Insert a pin on each Trigger to join the two parts together.

Step 19: You're Finally Done!

You're finally done! Here's how the final product should look like. This project will hopefully give you a better aim and gameplay in FPS shooter games & Battle Royale games.

Step 20: Remap the In-game Controls

For your project to work, you must go to your game settings and remap your desired buttons to the upper portion of your screen.

Step 21: PLEASE VOTE! <3

If you like this project, please vote it for the "Stick It! Contest"

Really much appreciated!Hope you guys enjoyed the project!

Stick It! Contest

Second Prize in the
Stick It! Contest