GTA
All Springer/NP/PCP Air Gun Discussion General => Air Guns And Related Accessories Review Gates => All Air Gun Accessories Gate => Topic started by: Novagun on May 20, 2022, 05:05:41 PM
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I have just bought Caldwell chronigraph from Amazon It came to me from Las Vegas . So the label says . It works well in natural light but
I can't get it to work inside my workhop either day or night i have tried led and incadescent lights and made sure no fluorescent light is running. I have seen the same machine running on you tube with just an ordinary table lamp. Any hints would be appreciated.
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I tried the same on my pro chrono.. I bought a light kit and they are infrared... No missed shots.. I bought the Caldwell light kit which is all led.. Let me know if you want the Caldwell lights..
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Yes please. I would like the Caldwell light kit The Amazon site says they are not available and will not be for some time.
Trouble is that I am in New Zealand ; far from the USA so cost might be a lot.
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Try this, get a sheet of white foam core board. Lay it on top of the diffuser supports and light it from the bottom. Use an incandescent or led laid on the table and pointing up at the board.
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These chronographs need to "see" two events (pellets passing over sensors under diffusers). They measure the time between the two optical "blips" to determine projectile velocity.
My suggestion:
Tape a piece of OPAQUE cardboard BETWEEN the two diffusers and then backlight the diffusers (from above) with the brightest incandescent lamp you have (>100W).
The front optical sensors will only see a bright front diffuser and the rear sensor will only see a bright rear diffuser as there will be a dim area between the diffusers. Without the "cardboard shade" the sensors may see both the diffusers and the direct light from the bulb which will confuse the device.
As the pellet passes each diffuser the corresponding sensor will detect the slight light change from ONLY that diffuser and should give a correct and consistent velocity reading. If the unit cannot get a velocity reading under those conditions it may be defective.
My Pro Chrono worked flawlessly with that setup for over three years... until the 500W worklamp burned out.
I then changed to DIY LED backlight for each diffuser and that has been error/miss free so far.
https://www.gatewaytoairguns.org/GTA/index.php?topic=198050.msg156309396#msg156309396 (https://www.gatewaytoairguns.org/GTA/index.php?topic=198050.msg156309396#msg156309396)
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I have just bought Caldwell chronigraph from Amazon It came to me from Las Vegas . So the label says . It works well in natural light but
I can't get it to work inside my workhop either day or night i have tried led and incadescent lights and made sure no fluorescent light is running. I have seen the same machine running on you tube with just an ordinary table lamp. Any hints would be appreciated.
Welcome to 60Hz and chronographs. LED lights that run on 120v are turned on and off 60 times a second and your chrony sees that flicker and you get all sorts of strange numbers. Even with incandescent lighting, a LED fixture in the room will still cause this.
The solution I found was to use LED strips that run on DC power, it works day or night, inside or outside, cheap and easy to do. Just peel off the liner and stick them under the sky screens. I use a battery pack to power them but a transformer or a car battery would work as well.
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not to hijack,
but the fx radar chronograph does away with ALL the problems of a regular chrono.
you can chrono in the dark if you wish lol
wish i had got one sooner!!
something to think about.
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Well it works. Pretty cool here today so I retreated to the workshop and made a light wooden frame and glued so opaque oven cooking paper to it. Shining 3 x 100 watt bulbs onto the paper over the light sensors and it worked on the bench in the daytime.
Thank you for your suggestions, they worked.
Radar chrony. Might be a bit exspensive here in the antiodes .
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Glad you got it figured out.
Just out of curiosity, may be relevant or not...
Over there in New Zealand are you 240v 50Hz?
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Glad you got it figured out.
Just out of curiosity, may be relevant or not...
Over there in New Zealand are you 240v 50Hz?
Its the sine wave that messes with the chrony, the actual Hz doesn't matter. DC provides a constant stream to the LED's, AC provides light 60/50 times second.
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Yep,
I was wondering if the change of Hz from 60 here to 50 there was making it more prone to error. ::)
But then I also thought Light Emitting Diodes were the solution because there didn't flash 60/50 times a second...
My Caldwell light kit has an AC to DC transformer and thought it would be the solution..... shows what I know.
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I have had good luck with the free Harbor Freight light ( two ) held with elastic strap to the sunshade.
https://www.harborfreight.com/144-lumen-ultra-bright-led-portable-worklightflashlight-63878.html (https://www.harborfreight.com/144-lumen-ultra-bright-led-portable-worklightflashlight-63878.html)
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Glad you got it figured out.
Just out of curiosity, may be relevant or not...
Over there in New Zealand are you 240v 50Hz?
Its the sine wave that messes with the chrony, the actual Hz doesn't matter. DC provides a constant stream to the LED's, AC provides light 60/50 times second.
Yes and no... there are exceptions.
Sine wave and PWM light pulses will mess with a chronograph reading.
FL light bulbs flicker A LOT actually at 120Hz (=2x60Hz) but most folks eyes don't notice. Incandescent HOT filament bulbs ALSO pulse at 120Hz but the THERMAL TIME CONSTANT of the hot filament is very large so the optical flicker is actually VERY SMALL. I've not had any interference from any incandescent bulb while using my chrono.
LEDs on steady DC diet are also GOOD! However, some "dimable" LED systems chop the DC into a PWM voltage/current to dim the LEDs. THAT high frequency pulsing of the LEDs looks continuous to our eyes but can provide even more interference than FL bulbs to optical electronics like chronographs.
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We are 230 volts at 50 hz. I thought that the incandescent filament didnt know that and didnt have time to cool off between current oscilations so steady light. Now after reading this thread I know different .
The important thing is that I didnt know and the opaque paper works well. Bit of a bugger really because I have found some guns a little tired.
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BUT.... now you know it.
That is the Beauty of a Chrono.
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Woops duplicate post.
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I have the Caldwell chronograph, and bought the LED shades because I was getting too many errors. When I started shooting my air rifles indoors I had all kinds of problems, and through the process of elimination I figured out I had too many competing light sources in my kitchen and it would give error after error even when I wasn't shooting. Then I got the bright idea to drape a dark bath towel over the LED lights and that cured the constant error problem. Works well now.