jimmy101 wrote:Technician1002 wrote:
Yes. On the t shirt cannon when scaling pressure/ speed and distance, we have lots of in barrel acceleration data. The variability is very little.
The shots became about as predictable as shooting the same rock over and over from a slingshot.
T shirt flight dynamics were all over the map, but Oranges become very predictable and repeatable.
Hey Technician1002, have you posted a description of your detection coil setup somewhere? Looks like it is working pretty well.
Ever tried using a laptop sound card instead of the storage scope? The scope's screen resolution is probably pretty poor compared to what the scope is actually logging. A sound card should be able to log the data about as well as the scope (at least for this type of fiarly low frequency data) and it is easy enough to extract more accurate readings once the data is on a PC.
Yes on both.
The write up on using the coils is documented on the official contest wiki.
From the home page, click on the barrel trim link in the menu on the left.
http://inteltrailblazerschallenge.wikispaces.com/
And yes again, I have used a sound card. It is documented on the same page.
Unfortunately my laptop screen is dead so it's easier to take the scope, shoot hard copy (uneditable results) and file them to pressure, projectile, and barrel groups. With the cursors on the scope, instant results were possible to view of all the coil crossings without math errors. Scope was used for convenience instead of precision.
If you do use a laptop, using Audacity gives very good results. If you can locate one of the inexpensive Behhringer USB interfaces ($40) they permit full 16 bit 44.1 KHZ stereo sample rate recording. (CD quality)
Other pages cover the construction and final game.
