RC Model Reviews

Tnx Thumond!

Truly minimalist. Trying to cram all the smoothing caps, for all the voltage regulators, in is a real headache.... but if it works without them this is the answer.

Love the heatsink. Off to the shed to dig up an old 'puter.

Phil

Kampala69 wrote:Tnx Thumond!

Truly minimalist. Trying to cram all the smoothing caps, for all the voltage regulators, in is a real headache.... but if it works without them this is the answer.

Love the heatsink. Off to the shed to dig up an old 'puter.

Phil

Thanks Phil,
In this case the 3.3V BEC takes care of providing the "clean" power for the transmitter module and a separate 2S LiPo battery powers it and the camera so there is no connection to the plane's (or other flying objects) power system.
Careful routing of wiring away from ESC's and motor is all that is required, however, flight test have not yet been done.

Thurmond

Per Bruce Simpson: "Under extensive testing at elevated operating temperatures I found that there original 3-terminal regulator was getting too warm -- so I've ditched it in favour of a charge-pump setup using a diode and capacitor (don't worry -- unless you have a background in electronics your eyes should have glazed over just then)."

Well, my eyes haven't glazed over. I'd just like to know the specifics of the charge pump setup. What are the exact parts needed, and exactly how are the parts connected to make the charge pump circuit? Does anyone with knowledge of electronics circuits know how to do this? This seems to be the only thing holding up the completion of this project for those willing to make their own circuit boards. With no ETA from Bruce, I would like to get this done before winter, as I'd rather not have to buy a bulky and inferior commercial setup with my limited funds.

With the FPV backpack project dragging on, no mention has even been made of the similar video receiver that Bruce uses, with a Foxtechfpv receiver module. Has anyone tried coming up with their own yet, or have you just bought one or two video receivers?

Had a look in the shed and dragged out a cremated Acer motherboard, and rescued a heat sink.

Also on the board were a couple of small ferrite torroids, and lots of dinky DIL pinouts, in several colours. These had not had the pins cut too short, so could be used to colour code connections on a stripboard set-up. They match with the pitch of stripboard and servo plugs - around 2.5mm.

Never thought I would get in to this recycling thing!!

Phil

sloperdude wrote:With the FPV backpack project dragging on, no mention has even been made of the similar video receiver that Bruce uses, with a Foxtechfpv receiver module. Has anyone tried coming up with their own yet, or have you just bought one or two video receivers?

My Take on the rest of the system:




Unused wires are Audio and Signal Strength.
5V UBEC from RC Timer for about $4.00
Module was part of a Transmit / Receive set from GoodLuckBuy.com but is the same as Foxtech.

Thurmond

I have to report that I started getting some "herring bone" lines in my video in bench testing my setup. I ended up adding a 470uF 35V capacitor across the output of the 3.3V UBEC to minimize them to imperceptible. I wish I had a O-scope so I could look at the output but I have not sprung for one yet. I did some more testing with some old Motorola cell phone Lithium Ion hardpacks (800mA). They run at a nominal 3.6V but freshly charged they are 4.1V. There was not any excessive heating of the transmitter module with a 4V supply and the picture was crystal clear and rock steady. I will test both power sources to see what is best for actual flying. I built a 2S pack equipped with balance plug from 2 of the cell phone batteries to power the camera itself. I really like lithium ion. I have 18650 size lithium ion batteries stripped from laptop battery packs that are still going strong after 15 years that I use in led flashlights.

Thurmond

What capacitor did you use on your receiver, Thurmond?

rotorz wrote:Hi pprioverde

That looks very interesting, I can see the fan sandwiched in there, does your camera run vey hot?

Wonder if you have a block diagram of what is in there and what voltages you are using?

Thank you for posting another interesting FPV AV unit.

Hey Rotorz

The camera does not run hot at all. The fans help to hold it together and help to cool the tx and regulator. Especially while I am testing my FPV gear. Those TX5823 modules get hot!. 9v is supplied by a hobbyking ubec and 3.3v is done with a linear regulator. I had experimented with a 3.3v ubec but out of two one was dead on arrival and the other only put out 3.2 volts which is below the spec of the tx module. The 9v ubec is not very accurate either. Fans are 5v each and are run in series off the 9 volts.

I am thinking next version I will just use linear regs around a central aluminum core that will also serve as a heatsink. Yes it is a waste of power but they are cheap and make less noise than switching regs.

Marc.

sloperdude wrote:What capacitor did you use on your receiver, Thurmond?

470uF 25V.

Thurmond