Lab Day 4

The idea I have for my final project is a leotard that will effectively regulate body temperature. The overall goal and function of this weareable technology would be to enhance ballet class and rehersal. I was also thinking about having a setting that you can turn on 5-10 minutes before class that will warm up your muscles, to allow for an even better class. This feature could also be used after a substantial break to avoid injury from jumping right into the material. I was even thinking that maybe it could regulate how much one sweats, and what the recomended dose of water is based off of that.

Preliminary Ideas (6/28):

  1. Nanotechnology sensors - smaller easier to attach to clothing
    • graphene is flexible
    • something lightweight
  2. Probably would just attach to the leotard in multiple places
  3. Protection - would like to somehow protect the device

Inspiration

  1. Polar Seals Wearable Technology

Final Project Progress - 6/28

During lab today, I built a circuit with a resistor and a thermistor. I also attahced three jumper wires to the ground, 5 votls, and A0. I then used a program in arduino that measures the temperature. My plan for this initial stage in the project is to show a change in brightness of an LED due to a change in temperature. I will do this initial protoype on a nano instead. From there, I plan to work towards replacing the LED with something that will change the temperature. I also have been thinking that I will possibily have manual and automatic componemts to this wearable technology. My idea is that the component that could heat the body up before class will be manual, and then the part that will cool the body down will be due to an automatic response of a certain temperature.

Make an Arduino Temperature Sensor

Code for Temperature Readings

Some things to keep in mind:

- The resistance of the thermistor must equal the resistance of the resistor
- The first jumper wire (yellow) goes to the 5V
- The second jumper wire (orange) goes to the ground pin
- The third jumper wire (green) goes to A0 pin

Circuit with Thermistor

Final Project Progress - 7/3

During lab today, I worked on soldering an arduino nano to a breadboard. Because this is going to be werable technology, I felt that it would be best to use a smaller circuitboard to make it more pratical. The key with soldering is to put the soldering iron on the metal ring which you want to solder. Then, you place the solder on the ring, but not touching the soldering iron. This way, as little solder as possible will get on the iron. Then, once the ring is hot enough, the solder witll melt and fill the gaps in the hole surrounding the pin, enabeling a strong connection. As you may be able to see on the image on the left, there is something around a couple of pins on the right side of the board. This is called flux. Essentially, if you ever put too much solder around the top of the pin, then there is a high chance that the electrical connection will be too weak. But if you squirt a little bit of flux on the pins where this is a problem, the flux will remove oxidized metal and prevent further oxidization, allowing a stronger connection.

Nano Arduino on Circuitboard
Nano Arduino Soldered on Circuitboard

Final Project Progress - 7/5
During lab today, I rebuilt the circuit above adding in a LED and with the arduino nano. For the arduino nano, you just have to place the pins in the same electrical line on the board rather than inserting them into the board as you do for an arduino uno. Circuit with LED, Resistor, and Thermistor
Next, I worked on loading the code onto the nano arduino (link to code above). However, I kept getting an error message that said there was a problem uploading to board. I made sure that under tools I had selected "Ardunino Nano" for the board, the Old Bootloader for the processor, USBtinyISP. For the port, however, the arduino nano was not an option, and all the other ports were hardware and did not work. In an effort to get my computer to recognize the arduino nano and create a port for it, I downloaded a serial driver. After downloading the software adn restarting my computer, there was still a problem uploading to the arduino nano. I asked around to other people who had used an arduino nano and both of them said that they did not have a problem. That said, they both had Windows computers and as I began to do more research, it seemed fairly likely that this was a mac issue.

Serial Driver Software

Ardunino Problem Uploading
Next, I used the multimeter (on the Ohm's setting) to measure the exact resistance of the thermistor and the resistors. For an accruate temperature reading, it is critical to have the same resistance as the thermistor. A higher temperature will be due to lower resistance. multimeter

I then used data points from a documentation of a typical resistance temnperature (attached below) to create a graph on Excel. I then inserted a curve of best fit with an equation. This way, I now have an equation that better models the conversion from resistance to temperature for the arduino code.

1974 Fenwal thermistors

Typical Resistance Temperature
Excel Graph Temperature vs Resistance

I then decided to use a digital thermistor. The readings that I got from that were much more accurate, although it was still slightly variable. I also added the LEDs to the circuit. I chose three colors (white, green, and blue), and programmed the arduino so that at the baseline temperature (around 24 C) all of them are turned off. Then between an additional 1 and 5 degrees, the blue one will light up. Then between an additional 5 and 10 degrees both the blue and the white will light up. And finally, above 10 degrees higher than the baseline, all three LED's will light up. The idea behind this prototype was just to show that I could use temperature change to affect another signal. As I have begun to explore it more, I am not sure that I will continue with trying to regulate temperature as the main ways taht I have seen this done has been through the use of carbon coated fabric that contracts when the wearer warms up and expands when the wearer cools down.

Code and Circuit Setup



I ran into quite a few problems getting this to work, however.
1. I could not get my computer (Mac Book Pro) to upload code onto the arduino - I kept getting the error message of "problem uploading to board" - I tried downloading a driver mulitple times - I tried rewriting the serial information in the software - But my computer would not recognize the arduino nano at all - For this prototype, the solution was to switch back to the Uno which worked well 2. The first (and old) thermistors I was using were not very accurate - I had to get the resistance of the surrounding resistors to match the resistance of the thermistor exactly - I tried using a multimeter to do this, but it required a lot of trial and error as long as some math and circuit diagrams as the resistance of the thermistor was about 360 Ohms - To solve this problem, I switched over to the digital thermistor 3. I also had trouble with the arduino code - This was because the code from the website that I was using had a differnet quotation mark and so my computer was reading this as a 342 stray error - By retyping this part of the code myself, I was able to upload the code to the arduino uno