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lgcirrus

I'm Hooked with Problems

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OK, I bought the cheapest camera from Heli-Hobby, and it has the unanticipated for me but anticipated for all of you problem of lines correlating to electric motor speed on my Slow Stick park flyer. What is the next step up for me - must be light. The video I did get with the motor off was awesome, and as we race these Slow Sticks, I really want my plane to be Race-Cam equipped. Any thoughts?

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Your best bet is to use a small LiPo just for the camera, I use a tiny pack that was ok on a plane half the size of a Slow Stick.

You could go down the route of switching regulator/filters but often for a plane this size it will be just as heavy and may not work as good.

Terry

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Is there any hope that ferrite rings or beads will solve my problem?

If your experience is anything like I have run into, you will need a combination of ferrite donuts, inductor chokes, and big value caps to clear out the power supply noise. But, YMMV depending on the situation.

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Your Mileage May Vary - in other words, every setup behaves differently, the only thing is trial and error. Give it a go and see the result.

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Thanks all. I will go for a small separate LiPo and ferrite beads. I wish I knew if I was beating a dead horse with an ordinary Speed 400 brushed motor with Electrifly C-12 ESC. Don't have the knowledge yet what size caps on the motor might help - what are "large" values? And what the heck is a flux capacitor, Oh I mean inductor choke? I'm e-challenged, but am always up for a challenge. LG

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Don't have the knowledge yet what size caps on the motor might help

That sort of solution would be a plan of attack if this was simple EMI/RFI. But it is not. Instead, the video "noise" is caused by motor commutation ripple that is superimposed on the battery supply. This is low KHz ripple, synchronized to the RPM, that often puts the Tx in a "brown out" sort of situation during the peak motor currents.

If you are using a good 3-Cell LiPO on the motor, and your airborne video equipment is rated at 5V (not higher), then you have a good chance for success. You will need to use a LDO Vreg (not a LM7805, but perhaps a LM2940T-5), with suitable caps (per data sheet). A high current 22uH choke on the Vreg input, and larger caps, may be needed too. Beyond that, a bit of experimentation, and luck, will complete the task. And the fine print: YMMV.

A dedicated battery supply nearly always solves the problem. A 2-cell 600mAH LiPO is just a few grams. Glad to hear that is what you plan to use.

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The latest news is that testing with a separate battery improves the signal significantly compared to the tap into the motor battery. Plus, vibration mitigation has significantly improved the signal. So there is progress!

I notice I run out of range rather quickly. For these little CMOS cameras with a 1.5" antenna, has anyone found that a Dean's antenna carefully installed will yield improvement on range?

Videos Improving

LG

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No a Dean's antenna is not designed for this frequency. The next step would be to improve the receiver aerial. Maybe a patch type like the GPP on this site.

Terry

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