My thermoelectric flashlight will emit light from my LED due to electrical power generated from my TEG. by using my own body heat from my hands, Along with heat sinks at the bottom to help with heat dissipation and cooling vents to help efficient heat transfer.

 

**MATERIALS USED**

1 Thermoelectric Generator - SP1848 27145 – 40 x 40mm 

1 Aluminium Heat Sinks - 80mm x 80mm x 27mm

XZCM2CRK53WA-8VF - Red LED

1 AstroAI Digital Multimeter - 2000 counts – AM33D

(V) 24 Gauge Silicone wire - Tinned Copper Wire

(V) Heat Shrink Tubing - Adhesive Lined 3:1 ratio

1 Boost Module DC-DC - XL6009

(V)  90mm x 3.2mm thickness Aluminium Round Tube - OD 90mm – ID 86.3mm

1 ON/OFF Switch - 12V 12mm Waterproof Latching Push Button/Silver

(V) Arctic Alumina Thermal Adhesive - 5g

4-6 WAGO Lever-Nuts - 221-412 –2 conductor – compact splicing

Copper Tape and Electrical Tape

**RESEARCH**

What is the Thermoelectric Effect?

Thermoelectric technology works by converting heat into electricity. This is done through two main effects: the Seebeck Effect and the Peltier Effect.

• Seebeck Effect: When two different metals or semiconductors are connected, and one side is heated while the other stays cool, a voltage (electrical potential) is created. The bigger the temperature difference, the higher the voltage produced. This is the principle behind thermoelectric generators (TEGs). The SP1848 TEG used in the flashlight converts heat into electrical energy by utilizing the Seebeck Effect.

• Peltier Effect: This is the opposite of the Seebeck Effect. When electricity flows through a junction between two different materials, one side becomes hot and the other side becomes cold. While the Peltier Effect is used in cooling devices (like thermoelectric coolers), in this project, it's not directly used, but the TEG works based on both effects (Seebeck for generating electricity and Peltier for cooling).

How Does the Thermoelectric Flashlight Work?

The thermoelectric flashlight uses a Thermoelectric Generator (TEG), which consists of a series of semiconductor materials. One side of the TEG gets heated (usually by a heat source like a campfire or body heat), while the other side is kept cool by a heat sink. The difference in temperature causes a flow of electric charge, generating a small electrical current that can be used to power a LED light.

In the case of the SP1848 TEG, it produces a small voltage when there's a temperature difference. For example, if the heat source is around 100°C and the other side is around 20°C, the TEG could produce a voltage around 4-5V, which is enough to power low-power devices like a red LED.

Key Components of the Thermoelectric Flashlight:

1. Thermoelectric Generator (SP1848 TEG): Converts heat into electrical power.
2. Heat Sink: Helps dissipate the heat, ensuring the TEG remains efficient and doesn’t overheat.
3. LED: A low-power red LED is ideal for this flashlight since it requires less energy to operate.
4. Boost Converter (XL6009): Steps up the voltage generated by the TEG to a level high enough to power the LED consistently.
5. Thermal Adhesive: Helps improve heat transfer between the heat source and the TEG to maximize efficiency.

Challenges and Solutions:

1. Inconsistent Temperature Gradient:

   • The temperature difference is crucial for generating power. If the heat isn’t applied properly, the TEG won’t work efficiently.
   • Solution: Use rubber caps to insulate the TEG, keeping the temperature gradient stable.

2. Low Power Generation:

   • A small temperature difference (like body heat) might not generate enough electricity.
   • Solution: Use a low-power red LED that requires minimal voltage to operate.

3. Heat Dissipation Issues:

   • If the heat isn’t dissipated properly, the TEG could overheat, affecting performance.
   • Solution: Use a larger heat sink to keep things cool and maximize energy conversion.

4. Voltage Problems:

   • The voltage from the TEG might be too low to power the LED.
   • Solution: Use a boost converter (XL6009) to step up the voltage, ensuring the LED gets enough power.

5. Wear and Tear:

   • The flashlight may get damaged easily with regular use.
   • Solution: Build the flashlight using durable materials like aluminum to make it stronger and more long-lasting.

Applications:

Thermoelectric flashlights are especially useful in situations where traditional power sources (like batteries) are unavailable. Some examples include:

• Camping and Hiking: Generate light using body heat, a campfire, or other heat sources.
• Emergency Situations: Provide a backup light source during power outages or natural disasters.
• Off-Grid Energy Solutions: Harness sustainable energy to power small devices without relying on traditional electrical grids.

Conclusion:

The thermoelectric flashlight demonstrates how we can use thermoelectric technology to convert heat into electricity and create sustainable, off-grid energy solutions. By addressing challenges like inconsistent heat gradients, power generation, and heat dissipation, this project shows how thermoelectric generators (TEGs) can be applied in practical and environmentally friendly ways. This flashlight could be especially useful in emergencies or outdoor activities where power sources are limited.

 

 

**CALCULATIONS**

Voltage = I * R = 200μV/K(Seebeck Coefficient)* 17K(Temperature difference)  = 3400 μV = 3.4mV

Current = V/R = 0.0034V/0.0257 ohms (resistance of my specific TEG) = 0.1323A =132.3mA

Generated Power from TEG = P = V * I = 0.0034V * 0.1323A = P = 0.0004498W = 449.8μW

Usable Power: assumed 70% so 449.8μW * 0.7 = 314.86μW

Thermal power input: 100 W (assumed value of heat transfer)

Boost Converter Efficiency: 314.86μW​/449.8μW​ * 100 = 70% 

Overall Efficiency: Efficiency = 0.00031486W/100W ​* 100= 0.00031486% (0.0003%)

Remaining Unused Energy: 449.8μW − 314.86μW = 134.94μW

 

Variables:  Independent: Temperature gradient

                  Dependent Variables: Voltage Output, LED Brightness, Power Output

                   Controlled Variables: TEG,  LED, Heat Sink, Wire type,  enclosure, surrounding area

 

1. First I use my thermal adhesive and apply it to the cold side of the TEG, then attach my heatsink to that side and wait for a few hours.
2. Then I connect the red positive wire of my TEG and connect it to the input (+) of the XL6009 boost converter. I then connect the black negative wire of the TEG to the input (-)
3. Connecting the output (+) to the ON/OFF switch, connect the other side of the switch to the positive pad on the LED, tape it using copper tape. Connect the output (-) of the boost converter to the negative pad on the LED
4. Use heat shrink tubing to clean up and protect the wires
5. Then I cut my aluminium tube to around 300mm as a starting length to try and fit my circuit inside. Once I find a starting length I then connect components to the tube using thermal adhesive and hot glue (not listed)
6. Attach the rubber cap at the end of my tube, for the flashlight side cut a square to fit the LED lens in place.

As I’ve been working on the thermoelectric flashlight, I’ve made a few key observations. First, the thermoelectric generator (TEG) seems to be responding well to the heat source. When I tested it briefly, I noticed that as the heat sink warmed up, the TEG started to generate some voltage, though not enough to fully power the LED yet. This shows the basic principle is working, but I still need to refine the system to make the energy output more consistent.

The heat sink is performing its job by dissipating the heat, but there’s a balance to maintain. If the heat isn’t sustained long enough, the TEG doesn’t generate enough power to keep the LED on. I’ve been experimenting with different heat sources to see how much time it takes for the TEG to generate enough electricity. So far, the heat sink is keeping things cool enough, but I think I’ll need to monitor its performance carefully during testing to make sure it doesn’t overheat.

The wiring and connections seem secure, and the silicone wire with heat shrink tubing is holding up well under the conditions. However, I’ll need to make sure everything stays tight once I start running it for longer periods, especially when testing the power output.

Overall, the observations so far confirm that the basic concept is working, but I need to optimize certain elements, like the heat source and power output, to get the flashlight functioning at its best.

For my thermoelectric flashlight project, the goal is to create a sustainable, off-grid power source by converting heat into electricity. I’m using a thermoelectric generator (TEG), specifically the SP1848, which works by converting heat differences into electrical energy. To ensure the TEG works efficiently, I’ve paired it with an aluminum heat sink to dissipate heat and maintain the temperature difference required for power generation.

Currently, I’m still in the process of assembling the components, which include a red LED, boost module (XL6009) to step up the voltage, and various wiring materials like silicone wire and heat shrink tubing to ensure proper connectivity. The TEG will generate power, which will be fed into the boost module and then used to power the LED.

At this stage, my focus is on making sure all the components fit together properly and that the wiring is secure. One challenge I’m facing is ensuring that the TEG generates enough power for the LED and doesn’t overheat too quickly. Since the system relies on a heat source, I’m paying close attention to the efficiency of the heat sink and the overall thermal management of the device.

Once the flashlight is fully assembled, I plan to test how well it works. Specifically, I want to evaluate how much power the TEG produces and whether it’s enough to keep the LED on for a reasonable amount of time. This project has the potential to be a useful, portable light source for situations where traditional electricity isn’t available. It’s also a great way to demonstrate the application of thermoelectric technology in everyday tools.

To sum up my project, its a portable thermoelectric flashlight that uses a thermoelectric generator to harvest body heat. A red LED is powered by a small voltage from TEG, boosted by a DC-DC boost converter. The heat sink efficiently dissipates heat, which means practically none of it (roughly 0.0004498%) escapes, so no discomfort is felt by the user. This provides an insight into body-powered electronics, where a wearable device could provide energy harvested from naturally occurring heat sources, thus cutting down dependence on conventional power sources like batteries. 

 

The thermoelectric flashlight has several potential applications, especially in scenarios where traditional power sources are unavailable. Since it generates electricity from heat, it could be used in off-grid situations, such as camping, hiking, or emergency preparedness. Imagine being in a remote area with no access to electricity; the ability to power a flashlight by simply generating heat could be a game-changer for providing light without needing batteries or charging devices.

This technology could also be useful in areas prone to power outages. During emergencies, the flashlight could be powered using alternative heat sources like a campfire, stove, or even body heat, making it a reliable backup light source when needed most.

Additionally, thermoelectric technology is being explored for sustainable energy solutions, and this project could demonstrate how thermoelectric generators can be used in everyday applications. It’s an opportunity to show that even small-scale, low-power devices can contribute to energy independence in certain situations.

While it’s not likely to replace traditional flashlights in everyday use, the thermoelectric flashlight could serve as an innovative, sustainable alternative for specific applications where battery power is unavailable or unreliable.

Error	How I’ve Fixed it
Inconsistent temperature gradient	Rubber Caps Both Ends
Electrical Connections in Circuit	Using Copper Tape
Heat Sink Heat Dissipation	Using a Large Heat Sink
TEG Low Power From Body Heat	Low Power Red LED
Bad Heat Transfer	High-Quality Thermal Adhesive
Output Voltage Problem	High-Quality Boost Converter (XL6009)
Wear and Tear of Flashlight	Aluminium Enclosure for High Durability
Measurement Errors	Calibrate Multimeter Often

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Inspired by Ann Makosinski 2013 Google Science Fair award-winning thermoelectric flashlight. I wanted to make one of my own. Instead of using a thermoelectric module like she did, I used a Thermoelectric generator which is made more specifically for converting heat into electricity. Instead of soldering the wires like she did I am using terminal blocks because of its more customizable traits. Most of my project was influenced by her so thanks to her and her original hollow flashlight.

**FULL CREDIT TO https://www.youtube.com/@amweekly1 FOR THE VIDEO AS IT IS NOT MINE BECAUSE I CANNOT MAKE A VIDEO BECAUSE I AM STILL BUILDING THE FLASHLIGHT** I HAVE GAINED PERMISSION TO USE IT AND WILL REPLACE IT VERY SOON** THANK YOU FOR UNDERSTANDING AND I AM OK WITH THE CONSEQUENCES I WILL FACE BECAUSE OF THIS**

IMAGE IS FROM https://www.instructables.com/Body-Heat-Powered-Flashlight-1/ FULL CREDIT TO THE HEADER IMAGE AS ONCE AGAIN THE PROJECT IS STILL IN PROGRESS AND I DO NOT HAVE A COMPLETE PROJECT TO DOCUMENT**