Quadcopter Build 6: Finishing and Adding FPV

Introduction

In the last instalment we installed and configured the software into the model and took our first test flight. The model is a basic quadcopter with the flight controller, ESCs, motors, receiver and battery all setup and working.

The last couple of steps are to now add the last few things onto the model to finish it off. In this article we will look at the selecting and adding the FPV camera and video transmitter (Vtx).

Adding a video camera and transmitter will allow you to fly the model using a set of FPV goggles or screen. It’s become one of the most popular ways to fly and the main reason that most builders make a model.

Why not add these items as part of the build before the test hover? It’s something I get asked about a lot and the answer comes from experience – the less there is on the model the less there is to consider as you troubleshoot any problem. Let’s have a quick look at trouble shooting if your test hover didn’t go as planned...
 
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New builders guide to troubleshooting.

For those builders of a certain age, methodical problem finding and repairing was something that was learnt fixing things round the house and tinkering with computers, electronics, machines, cars and motorcycles when they ‘went wrong’. With modern machines so much is removed from the user that the answer is often to simply restart it and hope the problem clears. If a ‘reboot’ doesn’t clear the problem then call in an ‘expert’.

Trying to understand the root cause of a problem with a quadcopter model can be overwhelming for a new builder so here is a few tips to help you find a problem;

Remember that what you are seeing on the model is the ‘symptom’ of the problem, not the ‘root cause’.

If you see that one of the motors isn’t starting with the others then the immediate thought is that it’s the motor at fault. It may be but then it also may be the connections to it, the ESC settings, and the signal connection from the ESC to the flight controller, the power connection to the PDB, the settings on the flight controller itself or a software problem on the ESC. Each of these things needs to be investigated and eliminating one by one to find the one that is causing the problem.

A visual inspection will normally give you a good idea...

One of the most common problems when testing a new model is that it flips on take-off. This is normally due to either two of the motors being connected the wrong way or one or more of the props installed incorrectly (upside down/on the wrong motor). All of these things can be checked just by looking at the model and tracing the wires and making sure that everything is as it should. Use build videos and troubleshooting videos on places like YouTube to help see what things should look like and don’t be afraid to ask – a polite, well thought out question will normally get a similar response.

Change one thing at a time...

It’s tempting to start swapping things as soon as you see the problem. Stop, think. Consider what it might be and search on the web for others who may have seen the same thing. Sometimes it’s not the obvious things that can cause the problem. I’ve had issues with the version of BLHeli and Betaflight here and that was stumbled on when I started to update things after a visual inspection showed that there wasn’t a problem with the wiring. So change one thing at once to see if it fixes the problem and keep a track of what you’ve tried as after half a dozen things you’ll start to loose track.

Make sure you have some basic test equipment

I was helping a fellow pilot via a phone call recently and we managed to narrow the problem down to two things – either the voltage out of the Vtx was below what his camera needed to work or the Vtx itself was broken. The fastest way to test this (without swapping the Vtx for another) would have been to simply measure the voltage out of the Vtx using a Voltmeter. A multi-meter/voltmeter can measure things like resistance, current and voltage is a valuable tool in case you need to check that what you think is happening – is. Invest in one if you are building or troubleshooting.

Keep all of this in mind when we look at adding the FPV gear to the model we’ve just made.
 

Choosing your FPV camera and transmitter.

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The two main considerations here for these pieces are 1) the available space to mount them into the frame and 2) how much you want to spend. Most frames are now designed to have space for both pieces but sometimes the frame design will only work well with a certain size of video transmitter and a certain size of camera enclosure.

FPV kit is often broken in a nasty crash so taking time to mount it securely and avoid smashing or snapping pieces off is well spent. It’s worth making sure that the camera lens isn’t protruding from the front of the model as this is often the part of the frame that takes the hardest hits. Recent frames we’ve built here have offered mounting holes that allowed you to mount the camera in several places so that no matter what you use you can mount everything securely and have the lens not sticking pact the rest of the frame.

The FPV transmitter usually gets warm in operation so a little airflow will be needed around it to help keep it cool. The most common problem with crashing is the antenna being bent so violently that it snaps off the SMA/RP-SMA connector from the Vtx itself. Many frames let you mount the video transmitter so that some of this force is absorbed by the frame and that helps save your Vtx from disaster. If you are even unlucky enough to rip the connector/antenna from a VTX whilst it’s powered on then even if you solder the connector back on then the transmitting electronics are probably damaged as they are designed to work with the load of the antenna attached.

Choosing the Camera

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Traditionally there are two main options – lower priced CMOS cameras that were slower and prone to ‘Jell-O’ effects (where the image looks wavy) or more expensive CCD cameras that were faster and handled light better. The price of CCD cameras has dropped in the past 6 months so you can now get a great CCD camera for about the same price as a CMOS camera.

Lots of pilots like the HS1177 Sony CCD based cameras; they provide great images, provide good colour saturation and light handling and also have an inbuilt menu so you can change how the camera performs to meet the needs of the flying location. These cameras now cost a lot less than they used to.

Many cameras now come in standard sized enclosures that fit nicely into the supports designed into modern frames. This makes installation a breeze.
Lots of other camera manufacturers have cameras that come with similar sized cases. RunCam have a number of cameras for different uses (low light, widescreen, narrower field of view) and Fat Shark have a number of cameras too for both traditional and widescreen goggles/screens. 

You can also try one of the cheaper options if space or money is tight. Our favourite if the Eachine 1000TVL CCD camera. It’s small and lightweight, had no menu or options you can change but works well and reacts to light changes quickly while providing a good saturation.

So what would I use? For me if it’s a cheap camera I want I’d use a Eachine 1000TVL, if I want a nice 4:3 camera I’d get a genuine HS1177 camera (some are now sold without the genuine Sony CCD sensor in them) and if it’s a 16:9 camera I want then it’s a Fat Shark 960 or RunCam Eagle we’d choose.

We’ve chosen a HS1177 camera here as we want to fly with a 4:3 goggle set. I’d reccoment looking at the RunCam Swift II and Eagle cameras, both are great and not too expensive.
 

Choosing the video transmitter

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The main thing to consider is how much space is there on the model. Many modern video transmitters support a full 40 channels (Bands A, B, E, F, and Race Band) and come in very physically small packages. Most have dip switches or a button to change the band and frequency they transmit on and have a LED display of some kind.

Some transmitters come with pigtails for the connection to the antenna so it can be screwed into the frame securely. This is a great way to avoid snapping the connector off the Vtx in a crash. I’d always consider this as an option if you have room in the frame you are using.

Some video transmitters now also let you select the power they transmit. This is a great feature that means that you can select the right power level for the country and location you fly in. Many race organisers will check the power of your FPV equipment and if you have more than 25mw you won’t be able to fly. Being able to select the power you are allowed to use is a very useful feature.

Check what voltage does the camera you are using run on. Most cameras will run on 5v or 12v but some, like the HS1177 and the RunCam cameras will support a wide range of voltages. Fat Shark cameras usually like just 5v so choosing a Vtx that provides the right voltage for your camera will make the cabling a lot easier.

Make sure that the SMA connector on the Vtx is the right one for the antennas you want to use too. RP-SMA connector on the transmitter will have a pin in the middle, for SMA connectors the Pin is in the antenna.

We have chosen the small Quanum Elite 40 channel Vtx that fits in the frame here.
 

Choosing the Antenna

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If you’re starting out with FPV then we’d always go with the Aomway antennas. They work well, are inexpensive and lots of places sell them.

When you get your video transmitters, you’ll find a whip style dipole antenna in the package with it. Put this in the spares box as it’s only good for testing, not for flying with.

There are lots of much more exotic and expensive antennas that you can use as you progress in the hobby. There are innovations coming out all the time with better performance and lower prices.

One of the latest ones that is causing a lot of buzz is the ‘Pagoda’ style antenna from places like MenaceRC. We are fans of them too..

Wiring them all up..

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Check what voltage the video transmitter needs and connect the power leads from it to the right places on the PDB. On ours here we will be using a 3s battery that will be great for the 12v the video transmitter needs. There are 12v pads on the PDB so we’ve simply connected our Vtx to that.

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If the camera is also a 12v capable camera then you can also connect the power wires from the camera to the same 12v output from the PDB. We did that here.

If the camera needs 5v then you can either use the 5v and GND out from the Vtx to power it (by far the easiest and the way we prefer if we have a 5v camera), or you can power it from the 5v pins on the PDB.

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The last cable if normally the yellow one from the camera and this sends the video image. It plugs into the video input on the Vtx, the video signal is the same on camera running on different voltages so you don’t need to worry about that.

TIP: Do make sure that you have the video goggles and camera set to the same video standard, PAL or NTSC. Most goggles have will auto select but on those that don’t it will mean you will not see the image.
 

Before you start installing to into the model..

Before applying any power to the video transmitter always install the antenna as powering the transmitter without one in will damage the transmitting circuity.

TIP: I’d always wire it up on the bench before installing it to make sure it works. I’ve had a few times when I’ve carefully routed cables, made connectors, soldered wires and found there was a problem! Check it all works then you can break it all down again and install it into the model.
 

Summary

By now you should have added your FPV equipment to the model and be able to fly line of sight and FPV successfully.

Pilots that fly models that have made themselves can usually repair the model faster as they know how it all went together and what was needed to get it flying in the first place.
Flying a model that you’ve made yourself is a wonderful feeling and allows you to create a truly unique model. Upgrading is easier too if you know how to take it all apart.

Pass on the lessons you’ve learned through the build to others, that’s how our video channel on YouTube started, we wanted to show others the problems we’d had and fixed so they could get back in the air faster.

Have fun, fly responsibly and be an ambassador for the hobby. Thank you for staying with the series and happy flying!
 
 
 
 
 
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