As some of you know I have built a high flash trigger for high speed photography. As it currently stands I have the sound detector, a simple light gate and moisture detector that system uses fantastically. However as time goes by I think about the use of something a little more powerful than a sharp object or a hammer. I took a trip to a small shop that sells air rifles and air pistols and found that the low end models have a muzzle velocity of around 300-350 feet-per-second.
I thought this was great, it will make a noise to activate the detector or maybe break a light beam to activate the system. When I told him about my plan and why I needed to know the muzzle velocity (he looked kind of puzzled when I asked him) I found that it can vary depending on air pressure and a likes.
now I could use trial and error, the error getting bigger as air pressure went down I thought that must be a better way. enter the gun chronograph, two gates the projectile must pass through with the time taken being measured. at 64MHz and the gate being 4cm apart and the provision of the hard ware the projectile cold be going as fast as 64000m/s (0.04m/0.000000625s) on the pulsin command. once the time is known and the distance which will be known anyway from equipment setup the time for the projectile to arrive at the target can be calculated and a successful image captured (tall order I know)
other than coding issues with the distance time calculations (time here will be a factor as it will only take around 9ms to travel 1 meter) I am struggle with a design for the detecting small projectiles. and cant immediately see a way of using the pulsin for 2 gates.
I would be willing for the system to spit out a number and manually set the time for a second shot, difference should be minimal
it would be ideal if I could not use an extra picaxe as the system already has a 28x2 that runs at 64mhz for detection loop (and has 3 spare programme slots) but receives signal from the sensors through the ADC comparator - i know the adc pins can be used as digital so would be ideal if I can use those instead of adding extra hardware pins but i will not totally reject the idea of using extra pins as hardware interrupt pins are still free.
more info of controller
http://www.picaxeforum.co.uk/showthread.php?26768-High-speed-photography
here's a balloon shot I did with a 70ms delay after sound detection. I never realise that talc glitter and static electricity could make such wonderful images.
Talced-balloon by f2268d215cc925918731918f4efa0289, on Flickr
if you guys think this isn't going to be possible I may drop it and just use trial and error. but this would be something that would be pretty darn cool to have
I thought this was great, it will make a noise to activate the detector or maybe break a light beam to activate the system. When I told him about my plan and why I needed to know the muzzle velocity (he looked kind of puzzled when I asked him) I found that it can vary depending on air pressure and a likes.
now I could use trial and error, the error getting bigger as air pressure went down I thought that must be a better way. enter the gun chronograph, two gates the projectile must pass through with the time taken being measured. at 64MHz and the gate being 4cm apart and the provision of the hard ware the projectile cold be going as fast as 64000m/s (0.04m/0.000000625s) on the pulsin command. once the time is known and the distance which will be known anyway from equipment setup the time for the projectile to arrive at the target can be calculated and a successful image captured (tall order I know)
other than coding issues with the distance time calculations (time here will be a factor as it will only take around 9ms to travel 1 meter) I am struggle with a design for the detecting small projectiles. and cant immediately see a way of using the pulsin for 2 gates.
I would be willing for the system to spit out a number and manually set the time for a second shot, difference should be minimal
it would be ideal if I could not use an extra picaxe as the system already has a 28x2 that runs at 64mhz for detection loop (and has 3 spare programme slots) but receives signal from the sensors through the ADC comparator - i know the adc pins can be used as digital so would be ideal if I can use those instead of adding extra hardware pins but i will not totally reject the idea of using extra pins as hardware interrupt pins are still free.
more info of controller
http://www.picaxeforum.co.uk/showthread.php?26768-High-speed-photography
here's a balloon shot I did with a 70ms delay after sound detection. I never realise that talc glitter and static electricity could make such wonderful images.
Talced-balloon by f2268d215cc925918731918f4efa0289, on Flickr
if you guys think this isn't going to be possible I may drop it and just use trial and error. but this would be something that would be pretty darn cool to have