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Museums and trade shows have a problem: how do you keep a physical exhibit engaging for the thousands of people who walk past it every day? Static displays get ignored. Touchscreens are a start, but they often feel disconnected from the physical object they are meant to showcase.

We were approached by a client who had exactly this issue. They had a beautiful, high-value product display for an upcoming exhibition. The problem? Visitors walked by, glanced at it, and moved on. They needed a way to pull people in and hold their attention.

Our solution wasn't just another screen. We built a custom interactive installation that felt like a physical product experience, not a webpage. Here is how we did it.

The Core Challenge: Physical Interaction

The client’s initial ask was simple: "Make it interactive." But we knew that a standard touchscreen mounted next to a product would only get us so far. We wanted to merge the physical and digital worlds.

The idea was to turn the display itself into a giant, functional button. We proposed a system where visitors would physically press a large, custom-built button on the plinth. This action would trigger a high-resolution video and an animated product teardown on a nearby screen. It’s a simple concept, but the execution required careful hardware and firmware design.

We needed a system that was:
- Reliable: It had to run for 10+ hours a day without crashing.
- Responsive: The feedback loop between pressing the button and the screen reacting had to be instant (under 50ms).
- Durable: It needed to withstand constant, sometimes aggressive, pressing from the public.

Why Raspberry Pi? Why Not an Industrial PC?

We get asked this a lot. For a project like this, an industrial PC is overkill. It’s expensive, bulky, and generates heat. A standard Arduino is too weak for the video playback we needed.

We chose the Raspberry Pi 4 Model B for a few specific reasons:

1.  Hardware Acceleration: The Pi 4’s VideoCore VI GPU handles 4K video playback effortlessly. We could run a seamless loop of high-quality content without stuttering.
2.  GPIO Pins: The general-purpose input/output pins allowed us to read the button press directly via a simple Python script. No complex serial communication or USB controllers were needed.
3.  Cost-Effectiveness: For a single installation, the Pi is a fraction of the cost of a dedicated media player or mini-PC. This kept the client’s budget focused on the physical build quality.

The Hardware Build: More Than Just a Button

The "button" was the tricky part. We didn't want a cheap arcade button. We wanted something that felt premium and substantial.

Our team designed a custom PCB (printed circuit board) in KiCad to handle the button's signal. Instead of a simple digital read, we used a capacitive touch sensor IC (the MPR121) to detect the press. This allowed us to make the entire top plate of the plinth a touch-sensitive surface, even if the visitor pressed slightly off-center.

The system architecture was simple:
- Input: MPR121 Capacitive Touch Sensor -> I2C Bus
- Brain: Raspberry Pi 4 (running a custom Python script using the `gpiozero` library)
- Output: HDMI to a 4K display

We also added a solid-state relay to control the ambient lighting around the plinth. When the button was pressed, the lights would dim, the screen would wake from sleep, and the video would play. When it finished, the lights would return to their idle state. This created a clear "start" and "end" to the interaction.

Firmware and Software: Keeping It Snappy

The software stack was built on Raspberry Pi OS Lite (the headless version). We wanted to minimize background processes to ensure the video playback had full priority.

Our firmware engineer wrote a multi-threaded Python script. One thread continuously monitored the I2C bus for a touch event. The other thread handled the video playback logic using OMXPlayer, which leverages the GPU directly.

The critical metric was latency. We measured the time from the physical press to the first frame of video. We got it down to ~80 milliseconds. That’s faster than a human’s blink, so the interaction feels instantaneous and magical.

We also implemented a watchdog timer. If the Python script crashed for any reason, the system would automatically reboot and relaunch the application. This was crucial for an unattended exhibition floor. We couldn't have a staff member manually rebooting a Pi every few hours.

Design for Manufacturing and Shipping

This wasn't a one-off bench prototype. The client needed this to survive shipping to the venue and be assembled by their own staff.

We designed the 3D-printed housing for the button assembly and the Pi enclosure in Fusion 360. The design accounted for thermal management—we added a small heat sink and a fan to the Pi’s CPU, as it was enclosed in a sealed plinth.

We also created a "plug-and-play" harness. The Pi was mounted on a custom acrylic plate with all the connections (power, HDMI, I2C) routed to a single breakout board. This meant the client only had to connect three cables to get the system running. We shipped the entire prototype to the US, and the client assembled it on-site in under 30 minutes.

The Result: A Crowd Magnet

The installation was a success. The client reported that the physical interaction significantly increased dwell time at their booth. People were not just walking by; they were waiting in line to press the button and watch the animation.

From our perspective, the project was a perfect example of vending machine development—not in the traditional sense of dispensing products, but in the core mechanics of a self-service kiosk.

The project required:
- Secure system control: Ensuring the device runs flawlessly in a public space.
- User-friendly interaction: Designing a physical interface that requires zero instructions.
- Remote management: We set up SSH access so we could monitor the system's health and update the content remotely if the client needed to change the video loop.

Final Thoughts

This project proves that you don't need bespoke, expensive hardware to create a high-impact interactive experience. The Raspberry Pi, combined with careful PCB design and clean firmware, can deliver a professional-grade installation.

If you have a product that needs to stand out at a trade show, or if you are looking for a partner to handle the hardware and software integration for your next kiosk or vending machine project, our team has the experience to take it from concept to a shippable prototype. We handle the firmware, the board design, and the 3D modeling, so you get a complete, working system—not just a collection of parts.