I am thinking to use a Bioelectric Impedance Analysis(BIA) Sensor from a digital skin analyzer to analyze skin humidity and oil conditions.
A few weeks ago, I went to ‘The Body Shop’ (A cosmetic brand) to buy a moisturizer. And a staff used the skin analyzer to test my skin conditions. I have doubts about whether the data is true or not. I found this skin digital analyzer in Amazon.
I thought it was cool because it shows two values; skin humidity and oil, so I bought it. Frankly, I am not sure what I am going to do with this sensor, but I bought it. I was curious about continuous skin conditions depending on situation, time and applied moisturizer.
I wonder how it works and I started to disassemble it.
It comprises a BIA sensor, power/reset push buttons, an LCD & led panel, a battery holder and a buzzer.
I wanted to get the values from Arduino, but I could not do. So I unsoldered the only sensor part and connected to Arduino. I used the Arduino Graph example code with Processing.
I only check the skin moisture value from the sensor, I am not sure how to get skin oil value. This value could be same if I were used two conductive metal to get the resistor value.
< Test Result >
- fingertips show the most humid value. (50~500)
- Palms has the higher moisture value than other skin area.
- the back of hands (except palm area) shows around 0~5 (hardly sensing)
- Just after applying moisturizer, the figure increased and it lasts less than 1 min.
(Left) after applying moisturizer within 1 min | (right) 2min later – Physiogel Lotion 
<Problem>
- I am not sure how to get oil value from the sensor. ( I think I should use the processor chip inside of the original devices.)
- Getting more sensitive and fine value from Arduino. (Original LCD shows the more detailed value. )
- Checking this value constantly (e.g 24hours), but not frequently(e.g. every 30 min)
- Finding the best skin area to examine.
<Plan (…Hope)>
- Build a wearable or attachable device, accessory or chip
- Send the data wirelessly ( maybe NFC, Bluetooth …)
- Simple application to record where I am sensing and time
- Alarm the dehydrated condition
Frankly, I am not sure the result from the sensor, is moisturizing important? should I use the expensive and high nutritious cosmetics? How many times should we apply them? I am not sure but I hope to find any interesting data from my ROY sensor.