A Few Projects

Show and tell for your homebrew nv projects. DIY 'Stickies' here too.
Trackerman
Posts: 134
Joined: 30 Oct 2017, 19:22
Location: ireland

Re: A Few Projects

Post by Trackerman » 24 Jan 2018, 14:34

Other way round Bruce, it passes 850 but blocks 940...
Agreed , I was surprised too.

I'll check to see if the underside is blue coated .

T

Trackerman
Posts: 134
Joined: 30 Oct 2017, 19:22
Location: ireland

Re: A Few Projects

Post by Trackerman » 24 Jan 2018, 17:27

Just checked the glass and it's only red no sign of a blue tint.

T

lightmesser
Posts: 540
Joined: 09 Jan 2014, 01:19
Location: Eastern Europe

Re: A Few Projects

Post by lightmesser » 24 Jan 2018, 19:42

Ir filter on sensor sucks no matter weather is it 940,850,UV,etc... It needs to be removed. It yields for that :)
Some manufacturers as I told in previous post recognized that and have distributed camera sensors without IR/uv fitted filter and with that they gave us choice color mode + night vision mode with easy lenses swap.


Sensor sees more clearer at the night and passes more IR light and if someone need it for daytime use(color rendering) it is also easy to add either IR/uv filer fitted lenses or simple filter addon in front of scopless, futon build or spotter build.

I currently use 5V cameras with 3,7-5V step up dc dc and I am running on single 18650 which is fairly large so for more professional look I plan to go to 1S 3,7V battery and same dc step up setup.

The biggest problem I have with mirror build is resolving eye relief of new small display. Nothing else... Everything else is piece of cake.

Trackerman
Posts: 134
Joined: 30 Oct 2017, 19:22
Location: ireland

Re: A Few Projects

Post by Trackerman » 25 Jan 2018, 12:59

Folks,

Something new... not for the non-technical folks, but some might attempt this if your soldering skills are good.

I found that the basic variable resistor mod to the LCD display was not good, when the LCD was dimmed the current draw went up!!!
mine went from 350mA ro 600mA when dimmed.

I investigated and found out why, the additional resistance was forcing the inverter circuit to drive harder thus pulling more current, the extra current was being dissipated as heat in the variable resistor.

So I have come up with a better mod which breaks the inverter feedback loop and dimms correctly.

Now the dimmer current draw is 200mA and full bright is 350mA (measured with camera also connected to battery, it also draws about 100mA alone).

So.. this is the circuit before the mod
Image

and this is the mod, cut the feedback line, add a 47k 1/4 watt resistor to the 19v rail and a 1k pot in the feedback loop as follows:

Image

and this is how it appears when implemented, cut the track between the white and black wires, i.e.the track between the 8.2 Ohm resistor and the IC.

Image

hope this helps someone...

PS, I should add that the range of dimming with this mod is smooth/linear across the whole pot travel. Not like the older mod which dims out completely in the first 1/3rd of a turn.

The LCD screen I am using is the standard type:
https://www.ebay.co.uk/itm/New-5-800-48 ... 2749.l2649

And the POT is from Maplin:
https://www.maplin.co.uk/p/1k-andohm-mi ... eter-jm69a

Cheers
Tracker

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MrNewbie
Posts: 298
Joined: 22 Dec 2012, 21:28
Location: Grafton, Ohio USA

Re: A Few Projects

Post by MrNewbie » 25 Jan 2018, 17:16

Why ???????????

The standard monitor..the one you pointed to above has its own menu, set it then forget it

(The brightness, contrast, and color are adjustable through buttons at the back of the monitor)

Trackerman
Posts: 134
Joined: 30 Oct 2017, 19:22
Location: ireland

Re: A Few Projects

Post by Trackerman » 25 Jan 2018, 19:01

MrNewbie wrote:Why ???????????

The standard monitor..the one you pointed to above has its own menu, set it then forget it

(The brightness, contrast, and color are adjustable through buttons at the back of the monitor)
Have you ever used one in a dark field?
Ask someone to look at your face when using it... the bright screen lights up your face and can be seen by the critters.
Some folk choose red or green filters to reduce the glare, this is just a way to dim the screen without filters...
Being adjustable it's more versatile for all conditions.

And the standard brightness adjustment only adjusts image intensity, does nothing for the backlight which causes the face glare.

Test it in a darkroom , stand in front of a mirror, you will see what I'm talking about.

T

phoenix
BRUCE ALMIGHTY
Posts: 4752
Joined: 09 May 2012, 14:40
Location: Aberdeen

Re: A Few Projects

Post by phoenix » 25 Jan 2018, 19:10

Trackerman,
Nice job - well done - that's a big improvement over the simple pot control.

Cheers

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

Trackerman
Posts: 134
Joined: 30 Oct 2017, 19:22
Location: ireland

Re: A Few Projects

Post by Trackerman » 25 Jan 2018, 19:20

phoenix wrote:Trackerman,
Nice job - well done - that's a big improvement over the simple pot control.

Cheers

Bruce

Your welcome Bruce, least could do is to share it after I've learned so much from you guys.

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snoopy
Posts: 2619
Joined: 22 Jun 2012, 23:22
Location: NER NER LOL stoke on trent

Re: A Few Projects

Post by snoopy » 26 Jan 2018, 17:25

i may be missing a bit but wouldnt it be easier/simpler to just use a single olson and star with a dimmer? they dim down a fair bit.

(asuming the multiple leds on the diagram were the through the hole types)

eather way limit the current and dim away

https://www.ebay.com/itm/DC-New-1-8V-3V ... 100623.m-1
'who is that masked man? its the kemosabby der..the bloody injun tells you every week!'

Trackerman
Posts: 134
Joined: 30 Oct 2017, 19:22
Location: ireland

Re: A Few Projects

Post by Trackerman » 26 Jan 2018, 17:45

Yeah I think your missing it.

The LCD display has a backlight, it illuminates the LCD screen, this light is bright and lights up the users face.
Its got nothing to do with the image or the IR source.


T

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