teacher trying to learn

Hello--I am a physics teacher and I have bitten off a bit more than I can chew! My students are working on a project to design, build and program a 2L water rocket carrying an Arduino payload (Uno, accelerometer, pressure/force sensor and altimeter). We are hoping to be able to collect data regarding speed, acceleration and altitude, perhaps even being able to determine the amount of force with which the water rocket hits the ground upon landing. Do we need to have the SD cards on board to collect the data or can we program the Arduino to do that, or could we perhaps use a bluetooth?

Also, I have no idea how to help my students combine all this code. Is there anyone out there that can help me? Advice is appreciated.... thanks!

The Uno is too big and heavy for a water rocket. Use a Pro Mini or the Trinket from Adafruit instead.

To learn how to use Arduino and some particular device, like the ADXL345 accelerometer, google "arduino adxl345" for tutorials.

Get one device working at a time and by itself, and make sure you understand the code and the results, before putting everything together. Expect to take several months for this project, if beginning from scratch.

Both SD card and BT are options. Only I think an sd-card is more suited. Not limited by range and you don’t have to make software for the other end.

dinawingfield:
Also, I have no idea how to help my students combine all this code.

“Combining code” is already a terrible start. You need to write code and use examples to understand how stuff like libraries work. “Combining code” rarely gives nice code nor is it easier…

Agree that the idea of "combining code" as a bad start, although if device-specific functions are used, those can often be reused without modification in the final product.

For data logging I highly recommend the tiny, self contained Sparkfun OpenLog. You simply use Serial.print() to dump all the interesting data through either the standard serial port, or using any of several software serial libraries, through one other pin.

No libraries and no special coding required.

Some links that may help
Re-using code
Strategy for development
Troubleshooting

Well, it's easy enough to launch over and over, so start with the minimum. Be sure your water bottle rocket can lift the payload first. Top heavy loads on water rockets usually result in an unexpected trajectory. I'd recommend a pro trinket and a very small lithium battery. Put it all in a plastic bag and tape it near the nozzle, even out the weight.

Instead of a SD card, consider using the EEPROM that already built into the ATMega328p chip. Cause weight (and it's distribution) will be the enemy of success.

ChrisTenone:
Top heavy loads on water rockets usually result in an unexpected trajectory. I'd recommend a pro trinket and a very small lithium battery. Put it all in a plastic bag and tape it near the nozzle, even out the weight.

From my model rocket days I recall that the Center of Gravity (CG) must be ahead of the Center of Pressure (CP) to make a stable rocket. Adding weight toward the nose (or fins toward the tail) will do that.