Passive POE trick to save a buck

Kenjusticejr

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one of my favorite tricks is to wire up the RJ45 with the blue and brown pairs...I leave them hanging out...Then, I grab the power supply for whatever device I'm powering, chop it in the middle, strip the wires, and splice them onto the blue (for positive) and brown (for negative) to send passive POE down the cable... Works pretty good...only had one problem with a lack of volts/amps at the powered device....It's a nice alternative to true POE and cuts down on extension cords, and ugly wires hanging around the cameras......... IF anyone wants to know more about this trick, a simple google search will work to provide sufficient information... OR, just find out the size of your power jack and buy a passive POE splitter for (usually) less than $5.


An alternative to this is to modify an existing cable and add passive POE is to grab a razor blade and slice open the protective cover on the cable VERY carefully and expose the pairs about an inch back from the connector... With everything unhooked, cut the blue and brown pairs and cut the cable shield a few inches back to give you a few inches of blue and brown wires to work with... The blue is typically used for the positive connection and brown for the negative (in standard POE).. Then take your power supply and cut it at least 6 inches from the jack and strip the wires back to expose the positive and negative. Now, grab our favorite roll of electrical tape, or soldering gun, and connect the power supply at one end, and the power jack at the other end... Depending on the rating of your power supply, and the rating of your camera, switch, router, IR light, sensor, or what ever it is you are powering, it should work...

*** caution. TOO long of runs and not enough voltage/amperage = not enough watts to power your device...so, may take some trial and error to figure out if your (for example) 5 volt 1000 milliamp power adapter will provide enough juice to power your foscam at 50 or 100 feet...

volts/ohms = amps
volts * amps = watts (1000 milliamps = 1 amp)

voltage drop over long distances of wires is normal... an alternative to buying an expensive POE injector is to hop on ebay, or go to your local junk computer store and find a laptop, printer, phone, or any other power adapter with the same voltage, or slightly more, and put it to use...

One example is: for standard POE, find a 48v power supply that is rated at 500 milliamps...this will provide 24 watts... and chances are your POE camera doesn't use 24 watts... Then use the "splice" procedure above to add the 48v on the blue/brown pairs and you have considerably cheaper POE...

Another example is: something similar to my junk foscam that has a 5v 2000 milliamp adapter... can check ebay, or junk computer store, and find a 9 volt power supply with a comparable amp ratting, or more amps.... (even a 12 volt power supply will work but be careful, some cams might fry with too much voltage so do some research before you fry a cam trying to save $20)...... The 9 volt power supply spliced in the cable in the passive POE manner will work just fine on a long run... the reason is that the voltage drop over the distance cuts the 9 volts down and as long as you have enough amps to keep your wattage rating within specs, it will work perfectly.



So, to make use of all of this garbled theory/knowledge, i'll share my personal POE setup with you.. I was able to find a 48V power adapter that came from an unknown piece of equipment at my local junk computer store, gave them $10 bucks for it, even though they should have given it to me for about $2, considering they had $10-$15 each marked on about 1000 different mix/matched power supplies and they would never sell them...But hey, everyone has to make a buck... and I didn't have to wait for shipping.... I digress.... anyway, 48v 1amp is the rating...that = 48 potential watts of power... SO, I'm going to use it to power at least 2, maybe 3 of my 3mp bullet cams that will be running on between 25 and 100 feet of cat6 cable. I'm going to get a $1 power strip/bus common at radio shack or just about any electronics store, and put the 48v form the power supply to it, then grab the juice and run it into the blue/brown pairs on the cat6 cable, and have POE on those cameras for about $12.


BTW, there are several youtube videos that you can find relatively easy regarding DIY POE....

And to clarify, some of my success/failure... running a nice 2mp cam with IR's on the front of my house...powered in the attic with an outlet...RJ45 spliced for passive POE with standard provided power adapter over a 40 foot run of cat5..works perfectly... AND, I have the Ethernet cable plugged into an actiontek powerline 500mbps adapter.... I would have used standard POE with this cam, but I didn't realize it wasn't a true POE cam when I bought it...oh well..live and learn... Passive poe is working just fine... and there is a lot less mess in regards to wires going all around my house..... (would have just went wireless with this cam like it used to be for the previous 2 years, but got addicted to the better frame rate of wired connections).....


not sure how this post ended up being so long, but hopefully someone out there benefits from my ramblings.
 

Kenjusticejr

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Ohh, and obviously, from a professional point of view, a POE switch is the easiest, safest way to go.. Even an inexpensive POE injector works good... I suppose my thread is geared toward taking a camera that is Not POE and using POE to reduce the need for extension cords... So, you can take a non-POE camera and give it POE characteristics to help with installations in remote locations, or long cable runs.
 

pal251

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Not sure if I would use it but thanks for the helpful knowledge sir
 

vector18

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I'll stick to POE, and if POE is not available, than a local power supply on a seperate wire. But neat trick though.
 

Kenjusticejr

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ehh, not as scary as you think...for example, I'm getting ready to mount an old 640x480 leftover cam from my recent upgrade at my house... Putting it at my business, will be about 20 feet from the switch and power supply. Rather than run a 20 foot extension cord, I'm going to patch in the power for the camera (not a poe camera) into the blue and brown wires of the ether net cable. This will allow me to power the camera using the Ethernet cable and not have as many wires running through my rafters. I'll post a pic of the cable and setup (maybe later today if I can get my damn FTP server setup) shortly so you can see.

- - - Updated - - -

http://www.ebay.com/itm/Power-over-Ethernet-Passive-PoE-Adapter-Injector-Splitter-Kit-5v-12v-24v-48v-/121100493562?pt=LH_DefaultDomain_0&hash=item1c3226e2fa

basically, what I'm doing (for free) takes the place of the splitter listed above.
 
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Kenjusticejr

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Quantity: 1 Kit = (1) Injector + (1) Splitter Injector: RJ45 Male + Power In to RJ45 Female
Splitter: RJ45 Female to RJ45 Male + Power Out
Passive PoE - means that input and output voltage are equal.
Works with all DC powered non-PoE devices
Supports 5V, 12V, 24V, 48V
Power supply required for power input - simply use the power supply (wall transformer) that is provided with the device you are trying to power.
Uses industry standard 5.5mm x 2.1mm power plugs Can work up to 150ft (depending on the quality of the cable and the power draw of the device)
 

Kenjusticejr

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for whatever reason, I'm having difficulties getting snapshots attached... more to follow
 

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Kenjusticejr

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if the pic posted, this is the finished product...saved a few bucks...
 

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Kenjusticejr

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oh, anyway, that cam is up and running 45 feet away from the power supply with the "poor mans passive POE" method I have described...

My next venture is the 4 hikvision cameras I got in the mail today...2032's.... going to run true POE to them, except I'm going to use the same method of getting the 48 volts to the blue and brown wires.. I'm using the $10 48 volt 1 amp (1000 ma) power supply I got from my local junk computer store... chopping the end off and putting the positive on the blue wires and negative on the brown wires.. It's got enough amperage that i'll be able to power 2-3 cameras off of it, just by patching in the voltage from the power supply to the blue/brown wires.


Moral of the story is: I'm a thrifty person that would rather save a few bucks and do it myself than pay someone else..so, my DIY POE isn't for everyone, but if someone benefits from my posting, then good....If not, then ya all can just think I'm crazy...lmao...
 

hmjgriffon

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oh, anyway, that cam is up and running 45 feet away from the power supply with the "poor mans passive POE" method I have described...

My next venture is the 4 hikvision cameras I got in the mail today...2032's.... going to run true POE to them, except I'm going to use the same method of getting the 48 volts to the blue and brown wires.. I'm using the $10 48 volt 1 amp (1000 ma) power supply I got from my local junk computer store... chopping the end off and putting the positive on the blue wires and negative on the brown wires.. It's got enough amperage that i'll be able to power 2-3 cameras off of it, just by patching in the voltage from the power supply to the blue/brown wires.


Moral of the story is: I'm a thrifty person that would rather save a few bucks and do it myself than pay someone else..so, my DIY POE isn't for everyone, but if someone benefits from my posting, then good....If not, then ya all can just think I'm crazy...lmao...

And hope you don't burn the house down lol.
 

framednlv

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I hacked my Cat5 cable for the first camera I bought. It worked great but the cost of the TP POE switch was affordable so I switched it out after a couple weeks. I do have one camera that doesn't support POE so I'll buy one of the adaptors for it.
 
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