A Few Projects

Show and tell for your homebrew nv projects. DIY 'Stickies' here too.
phoenix
BRUCE ALMIGHTY
Posts: 4497
Joined: 09 May 2012, 14:40
Location: Aberdeen

Re: A Few Projects

Postby phoenix » 04 Jan 2018, 19:48

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Last edited by phoenix on 04 Jan 2018, 19:51, edited 1 time in total.
LAND ROVER - THE WORLD'S WORST 4X4 BY FAR

phoenix
BRUCE ALMIGHTY
Posts: 4497
Joined: 09 May 2012, 14:40
Location: Aberdeen

Re: A Few Projects

Postby phoenix » 04 Jan 2018, 19:50

phoenix wrote:Yep, wire it as a voltage divider, and maybe try a slightly higher resistance than 1K if your 1k fixed resistor didn't dim it enough.

Even if the LEDs are driven by PWM, lowering the upper voltage limit of the pulse using some sort of resistance between the pcb and the LEDs will also reduce the effective current going to the LED and hence control their brightness

Cheers

Bruce
LAND ROVER - THE WORLD'S WORST 4X4 BY FAR

Trackerman
Posts: 85
Joined: 30 Oct 2017, 19:22
Location: ireland

Re: A Few Projects

Postby Trackerman » 04 Jan 2018, 19:54

Excellent (in Smithers voice) :thumbup:

hutty33
Posts: 48
Joined: 05 Oct 2013, 19:29
Location: Houghton Regis, Bedfordshire

Re: A Few Projects

Postby hutty33 » 04 Jan 2018, 20:24

Texan wrote:I am going to build a raspberry pi scope with GPS, 9dof imu, maybe barometric, light sensor to trigger ir cut, etc. as close to ATN as I can get without dropping frame rate to low.


I started making a raspberry pi night vision scope a while back but managed to break the camera with improper handling (they are pretty delicate) and haven't replaced it yet. I don't know if you're aware but the camera modules aren't brilliant for this kind of thing (1/4" sensor) so range will be a lot more limited in comparison to the cameras normally used for night vision. If you are going to use a usb camera there will likely be latency/lag or if you use a camera with composite video and a usb video converter then lag will again be a bit of an issue.
The possibilities with a rpi for a nv scope are endless - multiple reticles and colours to choose from and from your own design, decent digital zoom by changing the usable resolution of the camera, live streaming, a variety of sensors for all manner of things and photos/video at the touch of a button. Depending on knowledge a laser rangefinder could maybe be used to auto adjust elevation of the crosshair for the given range, I was about to start playing with this when I broke my camera.
Something else to overcome is trying to build it 'bare metal' so only the software needed for the build is loaded, making for a faster boot time.
I reckon rpi's will start a new level in homemade night vision with all the possibilities they bring, good luck with it mate.

Texan
Posts: 17
Joined: 30 Dec 2017, 22:49
Location: Texas

Re: A Few Projects

Postby Texan » 04 Jan 2018, 20:35

Yes, I was hoping to use a usb security cam, but two problems with that. One, pi only has one serial port and I have not been able to find an i2c or spi gps module. Two, pi camera uses the gpu, so much higher frame rate.

Works well with a 950nm torch at the ranges I want.

hutty33
Posts: 48
Joined: 05 Oct 2013, 19:29
Location: Houghton Regis, Bedfordshire

Re: A Few Projects

Postby hutty33 » 04 Jan 2018, 20:44

Texan wrote:Yes, I was hoping to use a usb security cam, but two problems with that. One, pi only has one serial port and I have not been able to find an i2c or spi gps module. Two, pi camera uses the gpu, so much higher frame rate.

Works well with a 950nm torch at the ranges I want.


I'm only at amateur at best with rpi stuff and I tend to forget things quicker than I learn them lol, but could you use 2x rpi zero's linked/stacked to give an extra serial? The zero is cheap enough and small enough for 2 to be used if it could work.

Texan
Posts: 17
Joined: 30 Dec 2017, 22:49
Location: Texas

Re: A Few Projects

Postby Texan » 04 Jan 2018, 20:56

I had not thought to look, but there are usb to i2c converters. I will grab a low light usb security cam and see how bad the lag is.

lightmesser
Posts: 468
Joined: 09 Jan 2014, 01:19
Location: Eastern Europe

Re: A Few Projects

Postby lightmesser » 05 Jan 2018, 01:01

phoenix wrote:It significantly sharpened up the image during daytime by blocking visible light and allowing me to adjust the lens of the scope for IR only, and for NV use the IR filter passed the IR from the illuminator and the scope worked perfectly


Bruce you are really Almighty...

Why I never thought of that? That method will be tested on my mirror build. No need to wait for the night... I will put 850NM pass in front of the scope and adjust camera lenses at daytime :thumbup:

However I have dilemma 16 mm or 25mm for mirror build? 16mm seems to have missing edges and 25 has full image but little cropped? What did you used in your near eye mirror build and you promised to re upload pictures of your mirror build. I really need them...

Texan
Posts: 17
Joined: 30 Dec 2017, 22:49
Location: Texas

Re: A Few Projects

Postby Texan » 05 Jan 2018, 03:00

hutty33 wrote:
Texan wrote:Yes, I was hoping to use a usb security cam, but two problems with that. One, pi only has one serial port and I have not been able to find an i2c or spi gps module. Two, pi camera uses the gpu, so much higher frame rate.

Works well with a 950nm torch at the ranges I want.


I'm only at amateur at best with rpi stuff and I tend to forget things quicker than I learn them lol, but could you use 2x rpi zero's linked/stacked to give an extra serial? The zero is cheap enough and small enough for 2 to be used if it could work.


Just read an article about connecting two pi’s together. I think you may have solved my frame rate problem and maybe allow this to work on pi zeros. If I can get it to work on pi zero, it will significantly reduce the size of the whole build. If it works, I can take all of the sensors and the code that runs them and have one pi handle that. Then have that pi pass the data only over to the second pi that is handling the video in and out. Taking all that code out of the video pipeline should help a lot. In fact, with one pi just handling video and a little code to overlay data on the video stream a usb cam will probably work just fine.

THANK YOU!!

Trackerman
Posts: 85
Joined: 30 Oct 2017, 19:22
Location: ireland

Re: A Few Projects

Postby Trackerman » 06 Jan 2018, 15:11

lightmesser wrote:
phoenix wrote:It significantly sharpened up the image during daytime by blocking visible light and allowing me to adjust the lens of the scope for IR only, and for NV use the IR filter passed the IR from the illuminator and the scope worked perfectly


Bruce you are really Almighty...

Why I never thought of that? That method will be tested on my mirror build. No need to wait for the night... I will put 850NM pass in front of the scope and adjust camera lenses at daytime :thumbup:

However I have dilemma 16 mm or 25mm for mirror build? 16mm seems to have missing edges and 25 has full image but little cropped? What did you used in your near eye mirror build and you promised to re upload pictures of your mirror build. I really need them...


By pure coincidence I just tested the difference between 16mm and 25mm myself.
My scope has a native zoom of 3 to 9 x 42mm which is 'ok' but sometimes I find the x9 zoom to be a bit short and I would prefer a x16 zoom for the 130m fox shots.
So by changing the board lens from 16mm to 25mm it effectively crops in by a factor of 1.5
Yes the dark edges disappear as we are now looking at the middle of the projected image.
The effective zoom range on my scope is now 4.5 to 13.5 x 42mm with the 25mm board lens.
I think I prefer this and will try it out on next hunting trip.

And from examining the 16mm lens and 25mm lens I think the 25mm lens has a lower f stop too! It seems to let more light in!
It has a much wider input and exit glass elements. From my experience in SLR work I feel this 25mm will have better light transmission.
Not sure but just my opinion from looking at both lenses.

This is my 25mm lens, claims to be f1.4
http://www.cctvcameradvrs.com/25mm-cctv ... board-lens

This is my 16mm rated at F2
http://www.cctvcameradvrs.com/16mm-f2.0 ... _name=16mm

So on paper it's gathering twice the light.

Tracker


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