Data Logger (and using cool sensors!)

A lab report by Vini Tripathii

Part A. Writing to the Serial Monitor

a. Based on the readings from the serial monitor, what is the range of the analog values being read? 0 to 1023

b. How many bits of resolution does the analog to digital converter (ADC) on the Arduino have? 10 bits (2^10 = 1024)

Part B. RGB LED

How might you use this with only the parts in your kit? Show us your solution. Video: https://youtu.be/mDjBvPOfadM

Part C. Voltage Varying Sensors

1. FSR, Flex Sensor, Photo cell, Softpot

a. What voltage values do you see from your force sensor? Ranges from 0 (no force) to 1023(5V -- output for large amounts of force).

b. What kind of relationship does the voltage have as a function of the force applied? (e.g., linear?) The relationship is logarithimic as a small change in force corresponds to a large change in voltage (increase).

c. Can you change the LED fading code values so that you get the full range of output voltages from the LED when using your FSR? video 1 -- using force sensor to fade LED: https://youtu.be/spUxtUhEbzQ video 2 -- using force sensor to change LED color (it was hard to control the force to show the different colors): https://youtu.be/FZXDIQBEVHU The key function was map(value, fromLow, fromHigh, toLow, toHigh), map allows you to change the value range.

d. What resistance do you need to have in series to get a reasonable range of voltages from each sensor? I used two 10K resistors for a total of 20K

e. What kind of relationship does the resistance have as a function of stimulus? (e.g., linear?) Both are logarithimic though the in the photocell's case a linear approximation would also work well.

2. Accelerometer

a. Include your accelerometer read-out code in your write-up.

Graphic Display

Take a picture of your screen working insert it here!

Part D. Logging values to the EEPROM and reading them back

1. Reading and writing values to the Arduino EEPROM

a. Does it matter what actions are assigned to which state? Why? Yes, because if the "clear" action is state 1, the memory will be cleared on our way to read/write to memory.

b. Why is the code here all in the setup() functions and not in the loop() functions? Since only one operation (R/W/C) is performed at each switch state it would be inefficient to have everything in loop().

c. How many byte-sized data samples can you store on the Atmega328? 1024 bytes

d. How would you get analog data from the Arduino analog pins to be byte-sized? How about analog data from the I2C devices? Since the analog input ranges from 0 to 1023, and each byte of the EEPROM has a range of 0 to 255, divide by 4 or use the map function. For the I2C, data is sent in 8-bit bytes, and can be managed accordly.

e. Alternately, how would we store the data if it were bigger than a byte? (hint: take a look at the EEPROMPut example) If the data is too big for a single byte then multiple bytes should be used. The EEPROM procedures would have to be used several times

Upload your modified code that takes in analog values from your sensors and prints them back out to the Arduino Serial Monitor.

2. Design your logger

a. Insert here a copy of your final state diagram.

3. Create your data logger!

a. Record and upload a short demo video of your logger in action.