LED lighting for chrono
- Thread starter Jerry H
- Start date
M
mks
Guest
Jerry,
I bought some LED light sticks for this purpose (actually for cloudy outdoor conditions), but haven't tried them out yet. Would be interested to know if anyone else has already tried this.
Cheers,
Keith
I bought some LED light sticks for this purpose (actually for cloudy outdoor conditions), but haven't tried them out yet. Would be interested to know if anyone else has already tried this.
Cheers,
Keith
HuskerP7M8
Member
Dr Geoffrey Kolbe of Border Barrels said the following at this link:
http://www.border-barrels.com/articles/rimfire_accuracy/tuning_a_barrel.htm
“It was important that the 'jitter' on the measured muzzle velocity was minimized. In an attempt to minimize the jitter of the chronograph, an LED array forming a 'light bar' 6 inches long and of width 0.08", was placed 8 inches above each sky screen. This formed a thin light source above each sky screen of uniform and constant brightness along its length.”
Landy
http://www.border-barrels.com/articles/rimfire_accuracy/tuning_a_barrel.htm
“It was important that the 'jitter' on the measured muzzle velocity was minimized. In an attempt to minimize the jitter of the chronograph, an LED array forming a 'light bar' 6 inches long and of width 0.08", was placed 8 inches above each sky screen. This formed a thin light source above each sky screen of uniform and constant brightness along its length.”
Landy
M
mks
Guest
Interesting. I thought the 60 Hz AC was supposed to cause noise.
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4Mesh
Guest
Not all florescent lights are 60hz any more. Of course that's with an inverter. Usually if the frequency is higher, the voltage is lower. Considerably. Your LCD monitor probably has a florescent backlight running at 400hz or so.
The chronograph will probably be much less finicky if you use a decent power supply for the lighting, and power with DC. Just try to find one that doesn't have a lot of ripple. A crappy wall wart with a 1/2 bridge rectifier might work, but I'd think it would cause too much noise for the chrony to pick up shots every time.
I think the light screens for the CED's are all LED. Powered with batteries, which is the preferred method.
The chronograph will probably be much less finicky if you use a decent power supply for the lighting, and power with DC. Just try to find one that doesn't have a lot of ripple. A crappy wall wart with a 1/2 bridge rectifier might work, but I'd think it would cause too much noise for the chrony to pick up shots every time.
I think the light screens for the CED's are all LED. Powered with batteries, which is the preferred method.
A
AlanaOkumu
Guest
Sounds like a great idea! I've been meaning to try incandescent bulbs. Let us know how it works. FWIW, even though it's not supposed to, I have set mine up inside under florescent lights in my shop, and it did seem to work fine too.Led Strip Lights can also be used for this purpose.
The use of IR LEDs is definitely a plus because most of the sensors used to pick up the light are mainly sensitive in the infrared. Most light sources give off some infrared light that is why bright lights of about any kind work.
goodgrouper
tryingtobeabettergrouper
Jerry, I don't think LED's will work. At least, it didn't when I tried it years ago. I found out the reason it didn't was because a photocell used by most chronographs needs a constant light source, and as you may already know, LED's are not constant. They actually blink thousands of times per second. It's so fast your eye can't see it but the photocell can. If the bullet passes over the photocell in between blinks, there will be no shadow for it to see.
Since it was crucial for me to use my chronograph at night, I looked into how I was going to accomplish this. After talking with Dr. Oehler about it, he informed my why my LED experiment failed and sent me his "indoor/night" kit for my Oehler 35. It utilizes special "showcase" 40w bulbs placed in brackets on the top side of the diffuser allowing constant, bright light to shine through the orange diffusers.
Of course, all of this will be going away with the horse and buggy as soon as the new wave of RADAR operated chronographs come to market......they will read a bullet night or day, rain or shine, and they don't even need to be lined up with the bullet path to work. It's a definite game changer.
