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pinter75

Need a bit of help with voltages.

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Hi,

I am looking to reduce weight on my aerobird challenger wireless video setup. I have tried to get the plane airborne with this setup:

RECON_SETUP.jpg

RECON_UNDER.jpg

The 9v Cell is a tad too heavy I think. I would like to power the cam from the availabe power from the X-Port. The wireless camera takes 8v 200mw. I have an 8.4v 1000mAh NiCad pack that would provide enough volts, but I am a little fuzzy on current etc.

Would plugging the wireless cam directly into the X-Port power pins destroy the cam with over current?

Thansk for your help :-)

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The wireless cam almost certainly has a five volt regulator build into the connector. (see if there is any warning not to remove this connector from the cam and replace it with another...) Then replacing the 8 volts with a 8.4 volts supply doesn't matter to much. What the current concerns: this is only determined by the actual demand of the cam while in use. It will only be sligthly higher on 8.4 volts compared to working on 8 volts. But do remember that a freshly charged battery will have a higher output voltage than the stated 8.4. It can go as high as 1.6 volts per cell in the pack for a short period of time!

In my experience most of these cams are rated for a voltage of up to 9,6 volts. SO read the manual carefuly and see if you can find any comment on this. DO you know the make of your cam? I have a similar one and maybe we could compare our findings. IF the slight voltage difference is still causing you to worry, then place a 1n5001 diode in series with the plus line and this will drop the voltage by 0,6-0,7 volts.....

(b.t.w. how did you get the type of letteringon the pictures? I am looking for this type of font to make lanyards with "aircraft text" on them)

Hans Delemarre, www.delemarre.ciscon.nl

the Netherlands

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Hi,

Everyone I have spoken to thinks that an 8.4v Nicad will poer the cam ok. I had a wireless cam that worked except the cmos was dodgy. I plugged the cam into the xport (pins 1 + 4) and the camera got hot! Hence my concern with plugging the new camera in, alothough I think it may have been shorting out inside. I did double check the voltage on the X-port and it was around 8.2v

The cam has the regulator in the plug. First time I took it out I managed to strain and break one of the tiny wires from the output to the cam. I stripped back the top of the plug with a sharp knife to expose the PCB, then re soldered the wire. The plug is now a strain proof contraption made of heat shrink tubing and hot glue!

The font is USAF Stencil- free ttf from here: USSAF Stencil Font It has lower and uppercase variations also.

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Keep in mind that the 7-cell pack will be over 10 volts hot off the charger. Furthermore, when the motor is running, the voltage will quickly sag down below 8 volts and will be full of commutating ripple current from the motor load. This will cause video quality problems.

Another solution would be to keep the 9V battery and reduce the weight of your video system. For example, the wiring and connectors are heavy -- upgrade it all to lighter hardwired connections. Even the outer jacket of the battery can be removed to save weight. There may be other things you can do; Every little bit helps.

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