Project Overview
The real-world problem I wanted to solve is simple: outdoor tables look amazing with lighting, but cords, outlets, and battery packs are all annoying. They get in the way, they’re easy to trip on, and they don’t fit the premium look I want for ChippyCraft products. This project explores whether a lighting system can be powered using only the heat from the fire table itself.
Thermal Electric Generators (TEGs) work through the Seebeck effect, where a temperature difference across the module generates a small DC voltage that can be conditioned and used to power electronics. The system uses three TEG modules in series to harvest heat from a steel hot plate mounted above the burner. A boost converter conditions the TEG output to a regulated 12V DC bus. From there, a relay switches 12V power to a WS2815 LED strip, and a buck converter supplies 5V to an ESP32 DevKitC microcontroller. The ESP32 runs a red-white-blue demo pattern using the FastLED library and controls the relay with a dedicated GPIO pin.
Testing confirmed the control logic and wiring integrity (including correct data signaling to the LEDs), but it also exposed an important real-world constraint: addressable LED strips can draw a noticeable surge current at startup. Managing that startup behavior and ensuring stable power under real thermal conditions is the next refinement step as the prototype moves from “works on the bench” toward “works every time on a fire table.”
Demo Video: Thermo-Electric Infinity Table — live fire test
The Engineering Journey
Empathize & Define
I started by thinking about real users for this system: bar and brewery owners, and people who want a statement piece on their patio. Their main needs are clean aesthetics, simple operation, and “wow” factor at night. Cords running across the floor and battery packs sitting on top of the table both fight against that goal.
From that, I defined the problem as: “Create a self-powered infinity lighting system for an outdoor fire table that runs only when the fire is on.”
Ideate & On-Paper Design
I brainstormed several power options: hidden wall power, low-voltage landscape wiring, solar panels, and thermoelectric generation. Thermoelectric generators were the most interesting because they let the fire do double duty: heat and power. On paper, I sketched a basic block diagram:
Fire heat → steel plate → 3× TEGs (series) → boost converter (12V) → relay + buck → ESP32 + WS2815 strip.
I also drafted a “thermal sandwich” with TEGs clamped between a hot steel plate and aluminum heatsinks, plus rough pseudocode for the ESP32 to turn the relay on and drive a simple red-white-blue pattern.
The Messy Middle
The build process wasn’t a straight line. I fought with unstable TEG voltage, figuring out which ESP32 pins to use reliably, installing USB drivers so the board would even show up, and wiring the relay module correctly. I also accidentally ordered a 30A fuse instead of a 3A fuse, which forced me to slow down and double-check ratings and wiring.
Each time something didn’t work, I isolated variables and tested one change at a time: first verify the ESP32 and LED data behavior using known-good power, then confirm relay control logic, and only then bring the TEGs and boost converter into the loop. A key learning moment came during late-stage testing when brief LED flashes confirmed correct data wiring and strip integrity, but power sources shut down due to startup current spikes. That shifted my focus from “is it wired right?” to “is the supply stable under real load?” and reinforced the importance of testing systems under realistic electrical and thermal conditions.
Final Prototype
The current prototype ties everything together into a weather-resistant control box. The TEG harness comes in through a waterproof connector, feeds the boost converter, and then splits into the relay (for LED power) and buck converter (for the ESP32). All grounds are shared to keep the strip, the relay module, and the microcontroller in the same reference.
The ESP32 now reliably drives a 12V WS2815 strip using a static red-white-blue pattern at reduced brightness, and it switches the relay on a dedicated GPIO pin. The overall architecture is proven, and the remaining work is focused on consistent power delivery during LED startup and on optimizing the thermal stack so TEG output is robust across real outdoor conditions.
Technical Deep-Dive
Power Architecture
The as-built power flow looks like this:
The relay only switches the +12 V line going to the LED strip. All grounds (boost converter, buck converter, ESP32, relay, and LED strip) are tied together. This keeps the control side simple while still giving the ESP32 full authority over when the LEDs receive power.
Bench testing and connector rework confirmed clean 12 V at the LED pads and reliable data signaling, while later tests highlighted the impact of LED startup surge current on weak power sources. In the final configuration, the goal is stable operation from TEG-derived power with adequate conditioning and thermal performance.
Electronics & BOM
The main electronic components are:
- 1× ESP32 DevKitC microcontroller
- 3× Thermoelectric generator modules (TEGs) in series
- 1× Adjustable boost converter (TEG output → 12 V bus)
- 1× Buck converter (12 V → 5 V for ESP32)
- 1× WS2815 12 V addressable RGB LED strip
- 1× Relay module (5 V logic, opto-isolated)
- 1× Inline fuse holder with 3 A fuse for LED supply
- Assorted wiring, connectors, and a weather-resistant enclosure
A detailed BOM with part numbers, vendors, and estimated cost can be exported as a separate PDF or spreadsheet for instructor review.
Mechanical & Thermal Design
At the core of the power system is the Seebeck effect: when two dissimilar semiconductor materials in a thermoelectric generator experience a temperature difference (hot side vs. cold side), they produce a small DC voltage. By clamping the TEGs between a hot steel plate and cooler heatsinks, the system converts part of the fire’s heat flow into usable electrical power for the table’s lighting electronics.
Mechanically, the system is a steel plate that sits in the fire table’s heat zone. The hot side of each TEG is bonded to this plate with thermal paste, and the cold side is clamped to finned aluminum heatsinks. The goal is to maintain a strong temperature difference across each module while protecting them from mechanical stress.
In real outdoor testing, wind and ambient temperature made the thermal differential more challenging than idealized calculations. This reinforced that thermal management (heatsink performance, airflow, and consistent clamping pressure) is as important as wiring when the goal is dependable, self-powered operation.
Wiring from the TEG stack is kept short and uses appropriately sized wire to minimize voltage drop. All electronics live in a separate enclosure mounted away from direct flame, with cable grommets or glands to keep the box as weather-resistant as possible.
Controller & Software
The ESP32 is programmed using the Arduino IDE and the FastLED library. GPIO 18 is used as the LED data pin, and GPIO 14 controls the relay module. The Level 1 demo code below drives a static red-white-blue pattern and assumes the relay is active-LOW (which is common on many 5 V relay boards).
Future versions of the code will add brightness control, multiple modes, and a simple Wi-Fi web page so users can change patterns from their phone without needing a separate app.
About the Engineer
I’m Ryan “Chippy” Bostrom, a non-traditional Engineering Technology and Agricultural Business student at UW-River Falls and the founder of ChippyCraft LLC. My background is in welding, fabrication, and epoxy art, and I’m building a product line of infinity tables, patio sets, and lighting that blend industrial steel frames with custom lighting and epoxy work.
This project let me connect my hands-on fabrication skills with mechatronics: power electronics, microcontroller programming, and thermal design. It also serves a double purpose as both a graded E-Portfolio for GENG 389 and an early prototype for a real ChippyCraft product.
The process reinforced how much progress comes from iteration: breaking the system into testable pieces, proving wiring and control logic with simple experiments, and then chasing the real constraints that show up under load and outdoor conditions.
Skills Used
- Embedded systems: ESP32 setup, GPIO, and FastLED
- Power electronics: boost/buck converters and relay control
- Thermal & mechanical: TEG stack and enclosure layout
- Wiring & integration of 12 V LED strips
- Documentation and portfolio building on a live website
Where This Goes Next
Future versions will focus on polishing the thermal design, improving TEG efficiency, and hardening the power delivery so LED startup behavior is stable in the real fire-table environment. The long-term goal is to integrate this system into production-ready ChippyCraft patio tables and infinity lighting installs that can be sold to local bars, breweries, and homeowners.