I know many of you couldn’t sleep last night (and you may think it was over anxiety that UPS is going to pulverize your Glowforge into granules) but in truth that wasn’t it: You were worrying “how fast is my goat?” For those in the Boston area I am not referring to the speed of Tom Brady, but the 4-legged variety of goats.
So in reality this is a goat wearable. I know @Dan is now kicking himself right now thinking “damn, I could have gotten in on the ground floor of the burgeoning goat-wearable market, and instead I made a stupid laser…".” Well have no fear folks, your needs have been answered. This is the caprinometer 2000, capable of measuring goat acceleration in 3 axes with a range of 200g +/- and sampling around 500hz. The case is made of clear acrylic. And mounted inside is an Adafruit Feather M0 datalogger with a 3-axis ADXL377 200g accelerometer breakout board It records onto a 32gb microSD card.
Now I realize many of your are wondering WTF? Well have you ever wondered why goats don’t get concussions? Most of the neurologists I have spoken to do a bunch of handwaving that basically is summed up “evolution”. Thanks. But why. So there are 3 possibilities: they are smart enough to not hit their heads with more than 95g of acceleration (having been rammed by a goat, I don’t think this is true - it was like getting hit by a linebacker), second they could have some anatomic structure in their skull which prevents traumatic brain injury and finally they could have some magical biochemical process which removes the tau proteins. In a series of 30 goat brain necropsies published in the literature none had evidence of chronic traumatic encephalopathy (CTE like the NFL players). So the first step is to record how hard they do actually whack their heads and how much of the impact is rotational (higher risk for concussion). So hence the caprinometer 2000. There are holes in the side for the nylon wire-ties that will hold it onto the base of the goat’s horn. I am awaiting IACUC approval for animal research to start the project, which since this is a straight observational study of natural behavior in their habitat is pretty easy to obtain - in my casual interactions with this herd they whack each other around 10x/hour.
Actually one of each… The little goat is the aggressor in the herd (hence he is named Napoleon) he is the one jumped up onto m chest and Billy the white one next to me.
Years ago now at the Texas zoo was A lone Mouflan that had nobody to play with and would butt his head against a chain link fence. Seeking to learn how much force he could put into it I did a two-legged karate kick on my side of the fence and the ram did a perfectly timed hit on his. Even with the fence absorbing most of the force I could get about six feet distance from the hit. If I-phones were invented back then one could use the app, but sadly I was only able to have a subjective measurement
Curious to see if the acrylic can take the impact, I know its not taking the hit but still some serious forces.
Not sure if it was folk lore but my grandfather told a story of a mean ram that would ram the care taker, he got tired of it and stood in front of an apple tree, He moved out of the way in the last second, the ram hit the tree and dropped dead! Oops, He probably wan’t expecting that! Just wanted to “teach it a lesson”
I was worried about that too, and going to reinforce the joints with hot-glue for the case… The problem is I need a pretty rigid case to transmit the impact cleanly
Fastinating experment but from the things I’ve run across I think in the end you are going to need a sample rate at least twice what you have because the G forces that casuse injury and death tend to be quite low duration spikes.*
*don’t even ask how someone without a formal medical background knows this.
That is awesome! I’m definitely going to make one up for some of the engineering teams. it is cheaper than buying these: http://www.thepocketlab.com/
but the pocketlab units are pretty amazing for the cost. They are the swiss army knife of portable wireless DAQs, I have loved using mine for just about everything.
your design is cheap enough to do destructive testing in though, and can be made by the students!
.” Well have no fear folks, your needs have been answered. This is the caprinometer 2000, capable of measuring goat acceleration in 3 axes with a range of 200g +/- and sampling around 500hz. The case is made of 
clear acrylic. And mounted inside is an Adafruit Feather M0 datalogger with a 3-axis ADXL377 200g accelerometer breakout board It records onto a 32gb microSD card.
