Determining Acceleration on the Potato Gun My latest craze is potato cannons. I built an easy potato cannon powered with hairspray. I did not organize ratios of chamber volume to barrel volume, however i should have suspected pretty much since the potatos go far. Really far. I shoot them within an empty bean area plus they remain in the environment for ten seconds before striking the floor at things i guess is 300 yards away. I wish to measure it to be certain. I am most likely fueling the space from sheer amazement. However the potato goes really far. I acquired to thinking, though, which i may go beyond just shooting the taters, and really turn this into something helpful. If there is a method to determine the acceleration from the potato within the barrel, that might be super awesome. I have were built with a couple of tips on this to date:Probably the most complicated involves drilling holes on every side from the barrel. The holes could be every inch the whole entire barrel. On one for reds led’s could be installed and wired in parallel to stay on constantly. On the other hand photoresistors could be installed as well as wired in parallel having a microcontroller. Once the potato traveled lower the barrel it might block the sunshine to a few of the photoresistors and also the microcontroller would obtain a readout. If there is a method to program this complete system and obtain a graph on the computer from the acceleration/time curve, that might be awesome!! One other way would yield a less accurate number. Shooting the cannon upright and timing how lengthy it requires the potato hitting the floor would provide you with the initial velocity. Vf = Mire Gt, so: 2Vi = 9.81t . I’ve built numerous potato guns and also have since switched to air canons. By having an air canon you are able to control the inputs much better. Despite a potato gun the potato is departing the barrel at relatively extremely fast speeds much more than the terminal velocity from the potato because it returns to earth. The results of drag and also the Reynold’s number are extremely great. Essentially unless of course you shape the potato into an aerodynamic shape like a bullet the potato will quickly decelerate and can really start spiral and travel inside a path much like a corkscrew. Another issue is the muzzle velocity is a lot more than the terminal velocity so its speed rising is going to be considerably faster than its speed heading down.
Personally, i built the precise device you’re speaking going to measure it very precisely using IR LEDs and photo transistors. One factor you need to be cautious about is selecting the correct transistor. The projectile travels so quick that unless of course the go up and down duration of the transistor is extremely short 5 10 nS the transistor won’t really turn off. Initially when i first built the timer I didn’t know C and so i found a “pinewood derby timer” program online which i could use and capture the occasions and time them. Since that time I’ve learned C and Set up and also have created a program that enables you to definitely input all your cannon criteria (sensor location, chamber size, chamber pressure, barrel length, high power laser pointer,barrel diameter, projectile weight and size). Then your computer will explain the theoretical muzzle velocity after which appraise the actual velocity whenever you fire the gun.
Certainly one of my personal favorite items to shoot is table tennis balls and basketball cores. You’d be surprised about the harm that the table tennis ball may cause when departing the barrel at speeds locally of 450 miles per hour. Start recording on Audacity and shoot with the frames. Therefore Vf = Mire, after which mixing the 2 Vi’s produce 2Vi.
When the potato did not finish up below where it began (since the cannon takes place in mid-air), the equation deltaY = Mire(t) .5G(t2). The 2nd equation could be better, since it considers the modification in place (about 1m).
Would you like to measure acceleration within the barrel?
Or would you simply want the speed of teh spud because it leaves your device?
Should you simply want the speed, you will find things known as chronographs for guns that will work as they are. Google image look for chronograph skyscreen to determine what this stuff seem like.
The skyscreens seem like IR giving off diodes at the end from the V, and a few reflective tape in the bow. There’s likely a photograph transistor also calculating the reflected light at the end from the V, but I wish to stress that I have never witnessed one out of real existence. They must be homebrewable.
The very best chronographs use three skyscreens and average the outcomes.
For calculating the acceleration within the barrel, you have many options that gun individuals don’t.
To begin with, you will get obvious PVC tubing rather than the whitened kind. Also, IR light might pass through normal whitened PVC tubing. I believe your holes idea is a great one, except with no holes.
How about cheap laser pointers?
One factor Let me stress is by using phototransistors rather than the photoresistors you pointed out. Photoresisters, IIRC, Blue-violet Laser Pointer 1000mW don’t respond to light quick enough to determine precisely.
Then you need to determine the information. I’d offhand recommend an olde PC having a printer port, running FreeDOS or something like that. However, I’m unclear about how quickly you are able to sample the input ports around the parallel/printer port.