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Would I need to use resistors to run this mini cam?

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  • Member since
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  • From: Long Island
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Would I need to use resistors to run this mini cam?
Posted by robkoz on Friday, November 03, 2017 11:57 PM

Was looking into this mini cam to record my layout and live stream it to my devices/pc. Was going to put this on a powered flat car. Not good with electronics but would I have to use a few resistors? My layout is run by a NCE 5 amp power system?

If I'm right the NCE 5 amp puts out 14 volts

The mini cam's power requirements:

  • Power consumption: 260mA / 3.7V

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Posted by speedybee on Saturday, November 04, 2017 6:52 AM

No, resistors will not suffice. Resistors lower voltage by an amount that depends on how much current is passing through them. They are fine for simple things like LEDs, a more complex device like a camera should be given its rated voltage.

Your best bet is just battery power. A single rechargeable lithium cell like a 18650 delivers 3.7v; probably not a coincidence that this is what the camera is rated to expect. Or three rechargable NiMH cells in series deliver about 3.6v, which is close enough.

The problem with track power is that you have to bring it down to 3.7v and also ensure that a small interruption in track power due to a turnout or whatnot doesn't shut off your camera. You could rectify your DCC signal with diodes, put a big capacitor on it to filter the power and essentially be a keep-alive, and use an inline regulator like a LM317 to output 3.7v. All in all, easier to just stick some batteries to it.

  • Member since
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  • From: Long Island
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Posted by robkoz on Saturday, November 04, 2017 3:03 PM

Thank you. I figured it wasn't easy. This camera comes with a battery so I should just leave well enough alone and create a way to mount it.

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Posted by RR_Mel on Saturday, November 04, 2017 4:14 PM

robkoz

Thank you. I figured it wasn't easy. This camera comes with a battery so I should just leave well enough alone and create a way to mount it.

 

I went berserk building a camera car.  I had more problems obtaining a working camera than I did doing the fabrication on the flat car.
 
Depending on which USB connector is used on the camera it is doable to power it from the rails.  The USB charging voltage at the connector is 5 volts.  A simple bridge rectifier and a 7805 voltage regulator chip with a couple of small filter caps will easily keep the camera battery charged.
 
I’m working on post for my blog to show the entire project.  It took 5 cameras before I got one that would work over a four month period (China's slow boat 3 times US snail mail twice).
 
If you are interested send me an IM through the Forum mail.  I can send you the wiring diagram and parts needed to power your camera from the rails.  Piece of cake!
 
 
Like I said I went berserk.  The camera will rotate 180° powered by a remote controlled servo over Arduino Blue Tooth from my control panel.  The camera battery usage is not alwasy correct.  The Q7 and MD81S camera specs state 90 minutes record time per charge but with the WiFi on its a stretch to get 20 minutes on either camera.  For me that meant battery power on my flat car to power the Blue Tooth, servo and camera to obtain more time.
 
I use the WiFI as a view finder to a Android mounted on my control panel, the WiFi viewing software allows remote on and off record mode on the camera.
 
 
Mel
 
Modeling the early to mid 1950s SP in HO scale since 1951
 
My Model Railroad   
 
Bakersfield, California
 
I'm beginning to realize that aging is not for wimps.
 
  • Member since
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  • From: Western, MA
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Posted by richg1998 on Sunday, November 05, 2017 12:07 AM

You could probably do it with a small full wave bridge rectifier, SMD filter cap, LM317L, 200 ma voltage regulator, two SMD resistors and two SMD caps. I made a few circuits like that many years ago.

The SMD filter cap would be 22 ufd, the same used in decoders near the full wave bridge. They are small, square yellow caps with an orange stripe for the positive terminal.

Four one amp diodes with make a bridge rectifier. 1N4000.

No idea how much current the camera draws.

Using leaded components might make it slightly larger but not by much depending on your abilities.

Solder it all on a piece of Vero board.

The LM317L is a three terminal voltage regulator the size of a small transistor.

Online calculators with give you the resistor values.

Radio Shack use to sell the small full wave bridge rectifiers but you can find all this online.

Jameco Electronics and Alltronics are a couple online sellers

Rich

N

  • Member since
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  • From: Long Island
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Posted by robkoz on Wednesday, November 08, 2017 10:36 PM

I appreciate the in depth ideas but this is way beyond my expertise for the moment.

  • Member since
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  • From: Bedford, MA, USA
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Posted by MisterBeasley on Wednesday, November 08, 2017 11:24 PM

I put together a camera-car for my subway using a camera and DCC power supply.

I did this quite a few years ago, and the whole system is very far behind today's technology, but it still works.  It transmits a wireless signal to a receiver box that can be plugged directly into a TV or video recorder.

It needs more light than I have available in my subway tunnels, so I added LEDs both to the tunnels and to the front of the camera car.

There is a big problem with signal dropout as the train runs around the layout, even on the surface.  This can be remedied by using an onboard camera that records directly to a memory chip, but then you would lose the real-time aspect that mine provides.

But, y'know what?  I very seldom use it, as I don't show off the layout very often.  When I do run it, this is what it looks like:

 

It takes an iron man to play with a toy iron horse. 

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