Packing it all into the Syma’s body shell was fairly straightforward as there’s plenty of space for everything with no need for internal mods, and getting power from the switched side of the battery was simple thanks to easily accessed and well marked power pads atop the FC.
It all fit so nicely that the single modification I had to make was adding a radiused cutout beside the battery compartment door for the camera wires. The camera itself is held onto the body with two layers of 3M VHB. It’s a simple non-permanent solution that also lends some vibration damping.
It’s worth mentioning that placement of the video signal wire, the video antenna, the video transmitter, and the upconverter are all critical to keeping EMI interference to a minimum. The Syma uses brushed motors and they generate crazy amounts of noise. Allowing the video signal wire or transmitter to come close to a motor wire can make the transmitted video image virtually unwatchable.
I photographed a live video feed directly off my 854×480 resolution FPV monitor to give some idea of the video quality when using the smaller ultra-wide camera. The left half of the photo was taken with the Syma’s motors running (you can just make out a blurred prop) and the right half is with the Syma turned on but the motors off (the moiré pattern is a result of my focusing on the monitor pixels and has nothing to do with the video signal.)
As you can see, the motor noise is negligible and even at full throttle the video is still pretty darned clean (see below for sample video.)
All-up weight for the FPV components comes in at just 12g and while that may sound ridiculously light, for a machine like the Syma X5 that’s still a hefty payload — surprisingly the copter can still do flips on a fresh battery! Speaking of batteries, the X5 comes stock with a 500mAh battery but I discovered that Amazon sells a 600mAh upgrade for the X5 which effectively offsets the added drain of the FPV gear.
‘AB’ left a comment suggesting I try the Turnigy nano-tech 750mAh batteries so I picked up a couple to test. Three problems:
- There are two versions available from Hobby King and they virtually identical except one comes wired backwards [with regard to the Syma] which means you first have to remove the leads from the connector and swap them or you’ll destroy your X5. The ‘correctly wired’ version sold by Hobby King is identified as PRODUCT ID: 9210000105 and is intended for use in Walkera products.
- They’re much thicker than the standard 500mAh or even 600mAh batteries which means you’re forced to modify the battery compartment of the X5
- They are heavy. At 19.5g they are so heavy that when combined with the FPV mods the X5 is barely maneuverable. My advice would be to stick with the lighter 500mAh batteries.
This demo shows how the video looks when being received through an exterior wall — usable but a bit noisy. Note that when the video receiver is used through interior walls (i.e. flying indoors) or LOS outdoors the video quality is excellent.
|Watch the complete video|
I haven’t measured the actual range but I did find the video transmitter greatly outperformed the Syma’s transmitter. So much so that while flying inside the house I totally lost control after flying up a flight of stairs, down the hallway and into a bedroom. The video remained noise-free and crystal clear but the Syma was no longer receiving commands. A quick fix that resolved the problem was to open up the Syma’s transmitter and replace its little stub antenna with a full wave antenna. Nothing fancy, just a length of 20 AWG stiff copper wire cut to 122.6 mm.
To sum up I’d say overall the project was a technical success and [probably] the waste of a Sunday but hey, good times!
Major Parts Used:
- 1258MHz Pico Video Transmitter
- DC-DC 3V to 5V Upconverter
- Miniature video camera (lowest price)
- Miniature video camera
- Alternate miniature video camera
Minor Parts / Consumables:
- 15 ohm to 22 ohm 1/4-watt carbon resistor
- 470uF 10V electrolytic capacitor
- 10uF 10V electrolytic capacitor
- Heat-shrink tubing
- 3M VHB tape
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Original post date 02/08/2015