After testing 3 data logging devices, we came to a conclusion on which design we would like to implement into the final prototype MROC vehicle.
Here is an overview of some of the advantages and disadvantages of each device that influenced our decision:
Pros and Cons - Arduino Shield
- Easy Connection
- Minimal Space
- Most expensive
Pros and Cons - DS3231 RTC
- High performance
- Smaller parts
- Backup power supply
- Two separate parts
- Additional wiring
- Less portable
Pros and Cons - Nano Shield
- Lowest cost
- Simple build
- All parts included in kit
As shown in the cost analysis, the Nano logger kit is the cheapest at $46.28. This is mainly because the kit came with all the parts needed to test the logger.
The other two designs required components to be purchased separately, and it doubled the cost compared to the Nano.
After some thoughts and calculations, a 16 GB microSD card is not necessary for use and we can reduce the cost of both Arduino Uno designs.
- A text file created to gather data takes around 20 kB per 5 minutes (rough estimate) that the data logger is recording
- Multiply both values by 12 to get the amount of recorded data per hour = 240 kB per hour
- Multiply both values by 8760 to get the amount of recorded data per year = 2,102,400 kB per year
- A 16 GB holds 16,777,216 kB storage
- So, (16,777,216 kB / 2,102,400 kB) = 7.98 years of data the SD card can hold
The MROC will not be running for 8 years constantly, let alone a year. A 1 GB SD card (as included in the Nano kit) can hold plenty of storage for a text file. Also, SD cards are always replaceable.
Therefore, for the final data logger implementation, using a 1GB SD card is suitable.
Based on our first post under “Project Needs”, we wanted a design that was easy to build and economically beneficial.
By reviewing the pros and cons and the cost analysis of each design, we chose to implement the Nano design into the final MROC test circuit.
The Nano is the best option because it’s the most inexpensive, it’s feasible with setup taking less than an hour, and it is very user-friendly.
Also, the step-by-step instruction sheet that comes with the kit makes it easy to follow along, and there were no disadvantages!
Our next post will dive into the test circuit that logs data while the car is in motion.