I am teaching iStem next year for the first time and one of the units will be aeronautical engineering.
My plan is to buy some foam gliders from kmart and modify them.
The task for the students will be to create a parachute that slows the plane down when it is thrown from the top of a building.
To determine the success of their design, I want to be able to measure the speed of the aircraft or deceleration when it hits the ground. I have found some bluetooth data loggers online but the range will not be sufficient.
Can anyone point in the right direction for a data logger that records to an SD card or how to use an arduino with sd card to get it working?
I found this on the site:
Would this do what I need to do out of the box?
Additionally, I want to make a mechanism to release the parachute at a specific altitude. I am thinking about using a mini servo to release the parachute somehow. Would that be achievable or does anyone have a better way of completing such a task?
According to my brother who is a commercial pilot, if you balance the aircraft around the centre of gravity, it will still fly straight. I’m assuming it will just fall faster once it loses speed. Chances are I’m wrong about that but I’ll do some more research before I start prototyping.
The kmart planes are pretty big so hopefully they will still fly. The focus of the design for the kids will be the parachute so I’m ok if they fall pretty quickly. We will throw them from the top of a 4 storey building so I don’t really want them to fly too far. I will design the deployment system for the parachute, possibly using a spring loaded latch with a mini servo to release the parachute.
If I were to do this project, I’d be looking for a small microcontroller, probably something RP2040, a pressure sensor for altitude and an accelerometer.
I’d ditch the microSD since an impact might release the card loosing the rest of the data, micros these days allow for logs to be saved directly to the flash memory.
I’m not on my PC ATM but if I remember I can send through some links.
The openlog will do what you want off the shelf and might be worth a look in as these parts will require some soldering and programming to get working…
The items:
You’ll need some soldering experience and a soldering iron
I’d grab a small battery:
Make sure the battery is well protected and switched off when not in use.
Some time ago I designed a 3D printed monobloc to hold a Nano, a pressure sensor and SD card reader including the interconnecting wires. It was for someone on another forum who needed a robust lightweight assembly for use as a rocket payload.
I could be wrong but the open log artemis will only log the data without being able to use the data to make stuff happen. That would mean that I need the boards you are suggesting anyway. I am really not familiar with raspberry pi but I reckon I can get the physical parts to work with an Arduino Nano if I can get it to log data as well. Soldering is not a problem. The students will not be doing that part.
I would be surprised if an SD card was jogged loose by a foam glider hitting the ground, particularly if it has been slowed down by a parachute. If it is then I may have to go down the Raspberry Pi route you are suggesting.
Hi Mark.
It wasn’t my rocket project. I just designed a 3D printed monobloc to hold the three modules.
You’ll find the info you want from reading the full discussion here:
Another possibility to consider might be a flight controller for a miniature drone. These tiny PCBs have onboard accelerometer/gyros of course, and most of them use an open source platform called Betaflight or something. I believe they can log data out of the box too, if I remember right.
Would I need other sensors connected to it to get the data? Seems like a stupid question but I can’t seem to find an all in one solution other than the spark fun artemis. I may have to use an openlog solution if the artemis doesn’t give me a way of accessing the data that is is writing to release the parachute.
Most of what I learnt about drone FCs, I’ve forgotten in the last few months. But they have a little connector which you plug an adapter into, which you plug a USB cable into, and you can talk to them with a PC. I think they can log their sensor data to onboard flash memory, which you can read with the PC. Black box functionality, I think they call it.
But come to think of it, it’s probably just a whole other rabbit hole you can do without if you can help it
