So, I decided I wanted to build a flight computer. Sounds fancy, right? Like something out of NASA. Honestly, it started because I had a bunch of parts lying around from other projects that didn’t quite pan out. You know how it is, you buy stuff thinking you’ll build one thing, then get distracted, and end up with a box full of sensors and boards.
Getting the bits together
First thing, I needed a brain for this thing. I grabbed an Arduino Nano I had. Cheap, easy enough to find code examples for, figured it’d do the job. Didn’t need anything super powerful, just something to read sensors and log data. Then came the sensors. What does a ‘flight computer’ even need?
- Altitude: Grabbed a BMP280 sensor. Measures barometric pressure, you can figure out altitude from that. Supposedly.
- Movement: Found an MPU-6050. Accelerometer and gyroscope in one package. Tells you how it’s moving, tumbling, whatever.
- Location: Had a cheap GPS module too. U-blox something-or-other. Getting a GPS lock indoors is always fun, right?
- Storage: Needed to save the data. A little microSD card module seemed the way to go.
That was the plan, anyway. Just wire these things up to the Nano.
Putting it on a board
I started by breadboarding everything. Wires everywhere. Looked like spaghetti. Took ages just to make sure the power and ground lines were right. Didn’t want to fry anything on day one, though I usually manage to smoke at least one component per project.
Getting the sensors talking was the next headache. They all use I2C, this communication thingy. Sounds simple, just two wires. But getting them all working together, addressing them right… let’s just say I spent a lot of time staring at the serial monitor, seeing garbage data or nothing at all. Found some libraries online, mashed them together. Lots of trial and error. Mostly error.
Eventually, I got readings. Altitude seemed plausible. Acceleration numbers were flying around when I shook it. GPS… well, GPS took forever to get a fix, as usual. Especially near my window.
Once it vaguely worked on the breadboard, I moved it to a perfboard. Soldering time. My soldering isn’t pretty, but it usually holds. More wires, trying to make it compact. Ended up being a bit of a lump.
Coding the thing
The code itself wasn’t super complex. Read sensor A, read sensor B, read sensor C, write it all to the SD card. Repeat. Added some checks, like making sure the SD card was actually there and working. That tripped me up for a while; turns out my cheap SD card module was fussy about the card format.
Debugging was mostly printing stuff to the serial port. Is the altitude changing? Are the G-forces making sense? Is it actually writing to the card? Basic stuff. No fancy debuggers here, just good old `*`. It’s crude, but it gets you there. Eventually.
Did it fly?
Testing time. I didn’t exactly have a rocket handy. So, initial tests involved waving it around my head. Dropping it onto the sofa (gently!). Taking it up and down the stairs to see if the altimeter noticed. It sort of did. The altitude readings were noisy, jumped around a bit, but you could see the trend going up the stairs.
I stuck it onto a kite once. Got some data. Mostly just showed the kite bouncing around in the wind, GPS track was all over the place. The SD card writing worked though, logged a bunch of numbers.
So, yeah. I built a thing. Does it compute flight parameters? Kinda. Is it reliable? Probably not. Would I trust it on anything important? Definitely not. But it was a project. Kept me busy, used up some parts from the junk box. Learned a bit more about how fussy sensors can be. It’s sitting on my shelf now. Another project done. Ish.