In this tutorial, the application of Biocompatible Ferroelectret Nano-generators (FENG's] within the wearable market will be tested. FENG's can generate energy when being bent or folded and therefore are being compressed. By attaching the FENG's to the human body, power could be generated by walking.
Because these FENG's are still in development phase and are therefore difficult to obtain, a regular flex sensor has been used in this intructable. With the use of regular flex sensors, we will be able to measure the size and frequency of the bends.
Step 1: Necessities
- Flex sensor [4.5"]
- Resistor [10000k]
- Arduino Uno
- Breadboard + Jumper Wires
- LCD screen
- Soldering iron
Step 2: The Circuit
Above you can see how we have connected the flex sensor. It is advisable to use a resistance of 10000 Ohm.
In this example it was decided to use an LCD screen, so that values can easily be read. This, however, is not necessary.
Step 3: Code
The following code is used to read out the data. In this example we choose to use a delay of 100ms.
Step 4: Soldering
Once the code is tested and the flex sensor succesfully reads out the angle and the corresponding resistance (In the case of the piezo sensor, it will be proportional to the generated energy), is it time to solder the sensor to the wire. Depending on the set-up, a length of two meters will be sufficient to keep moving freely
Step 5: Attachment of Sensor to the Subject
After soldering, the sensor is attached to the test subject. Make sure that the subject has flexible clothing (preferably thermo-clothes) and that the sensor is given enough space to bend.
In this case, this is done by attaching the sensor on one side and guiding it on the other side.
Step 6: Read Out Data
After attaching the sensor it is time to collect data. let the test person run a bit and measure the values.
The output of the data when the sensor is attached to the back of the knee gives inconsistent values. Because the fleximeter is only fixed on two sides, a lot of buckling can be seen. This could be remedied by interwine the sensors in the clothing.
The values on the outside of the knee show a sinusoidal graph showing that (at a normal running pace) the sensor is bent and relaxed every 0.8 second.
Based on our prototype, we are sure that the implementation of FENG's into the wearable market is a realistic option. However, because the nanogenerators are still in development and are therefore nog yet available for consumers, we can not make an estimation on how much energy there can be generated per sensor.