Chapter 12. Expanding Your Drone’s Abilities

Congratulations! You have done it. You built your first drone, and you have learned a number of valuable lessons along the way. It is our hope that at least some of these lessons will resonate with you in a way that encourages experimentation in the future. This chapter gives you a few suggestions for modifications that you can make now that you’ve mastered the art of building drones.

Add a Camera and First-Person View

If you built the autonomous kit, it did not come with an FPV package or camera. Now that you are comfortable building these aircraft, it’s a great time to add a live video feed to see what your drone sees in real time. To do this, you will need to add a video transmitter on the aircraft and a video receiver to a ground station with some type of monitor (goggles or small screen) to view the feed (see Figures 12-1 and 12-2).

FPV Installation

The drone model, the Little Dipper, that we used as the build example for this book is a 300-class quadcopter, which is small compared to other drone designs. For this reason, to add FPV to such a compact quad, we recommend that you remove another component (that’s not vital for flight). If you have added everything shown in this book, there is already a good deal of electronics loaded onto your drone. For best flight performance, battery life, and overall stability, it is best to avoid trying to carry too much on your drone’s frame. If FPV is a must for you, perhaps removing the telemetry radio is the right way to go.  

Installing an FPV system can be an entire chapter of a book, and falls outside the scope of this one. However, if you are interested in the topic and would like to learn more, feel free to check out our online FPV page.

Figure 12-1. 5.8 GHz video transmitter with a right-angle adapter and right-handed Skew Planer antenna.

Figure 12-2. The Mobius action sports camera—a great option for an aircraft the size of the Little Dipper—is very popular due to its light weight and high performance.

Collect More Data with Other Sensors

APM is able to incorporate a number of additional sensors. Because this is an open source platform, you can even alter the firmware to react to certain sensor input any way you like. Perhaps you would like to use a wind speed sensor to slow down forward flight once a certain speed has been reached, or perhaps a proximity sensor to detect when you are a certain distance from the ground. This is all possible with a little research and some clever code. The fantastic DIY drone community that has sprung up online can serve as a very valuable resource for such projects.

Great Web Resources

A great way to get started writing custom firmware or incorporating custom sensors is to find others who have already experimented in this area, and build on what they have done. DIY Drones serves as a great community to link up with other developers.

If you are interested in writing custom firmware or software for your newly built drone, look into Drone Kit; it’s a new middle layer that sits on top of the original code base and allows you to easily write custom code in the Python language.

Altering Speed: Ready, Set, Race!

One of the first mods that we are always asked about when it comes to drones is how to make them faster. As you have already learned in this book, getting the desired performance requires a fine balancing act among all the components and the design. That same theory applies to speed as well. The major things to consider when trying to increase the speed of your quadcopter include:

Weight

As with anything that is built for speed, weight is the very first thing you should look at when trying to improve performance. Anywhere that you can shave a few grams will allow you to see some increase in your aircraft’s capabilities. The more you can shave off, the better you will be in the long run, even if it’s just a few grams here and there. Consider removing any parts that aren’t mission-critical. Do you really need that telemetry radio just to fly fast? What about the GPS? Maybe you want to replace the autopilot altogether with something that is much lighter. These are all things to consider when trying to reduce weight.

Prop size and pitch

As we learned earlier, the props are much like the tires on a car and can greatly affect the real-world performance of our aircraft. If you want to increase the speed of your quad, try experimenting with different props. The higher the pitch, the more air you will move through the prop, which generally equals a higher rate of speed. Be warned, though: there is such a thing as too much pitch. You may notice a decrease in stability of your aircraft at a certain point. Props are a fairly inexpensive part of this equation, so we will often buy several different types to play with and find out exactly how they perform on our own gear rather than taking advice online. Something that doesn’t work for someone else may work great for you, and vice versa. On the Little Dipper, a 6-inch prop is the largest that you can fit, so try experimenting with different pitched props of that size.

Battery voltage

In Chapter 3, we talked about how you can calculate the RPM of your motors by multiplying the battery voltage against the KV rating of your motor. In those equations, we only discussed a three-cell battery that has a voltage of 12.6 with a full charge. Each volt, as we already learned, has about 4.2 volts of power when fully charged. What we didn’t explore was the vast array of battery types out there. What if you changed your three-cell battery out for a four-cell? Now you are talking about a maximum voltage of 16.8 and an increased motor speed of 9,660 RPM! That can make a huge difference when building a racing quad!

Increasing Battery Voltage

Increasing the operating voltage can have an effect on your other components. Make sure that everything in the power train is rated to work properly with the voltage you plan to use. The ESCs, motors, and autopilot all need to be rated for the voltage that you are looking for.

Maybe the winning combination comes in the form of a smaller capacity (for lighter weight) higher-voltage battery (for higher RPM) combined with shorter props (for quicker response) that have a higher pitch (to move more air). Experimenting with all these different options is what we consider to be the fun part of building these aircraft.

Increasing Flight Times

The general rule of thumb for increasing flight time is to go with a longer prop that has a lower pitch. In the case of the Little Dipper kit, we have already bundled it with the 6-inch (largest that can fit on the frame) prop at a pitch of either 4.5 or 3. There may not be a lot of upgrade room left, but it is possible to experiment and see what you can do. At the time of writing this chapter, 6 × 2 props are just starting to hit the market, and they are a good possibility for longer flight times. Of course, decreasing the weight of the aircraft will also gain you a little more flight time, so look at that as another option to improve your air time.

Troubleshooting in the Drone Community

Our final recommendation in this book is that you come to terms with the fact that as long as drones are in your life, repairs and problem solving are as well.

Troubleshooting issues that arise and affect flight performance are a normal part of being a small UAV enthusiast. You will be completing routine maintenance and systems checks before each flight to minimize unfortunate events while flying, but repairs are inevitable. Luckily, you are not alone. As mentioned in Chapter 1, there is an entire, well-established online drone community that we encourage you to get involved with.  

Helpful and popular online forums include:

• DIY Drones is a really great resource if you are using APM components.
• MultiRotorForums.com is a fantastic resource filled with experienced pilots and beginners alike.
• YouTube has a multitude of drone tutorial videos. Check out the FliteTest crew.
• UAV component manufacturers may also provide helpful information. DJI has incredible print and online instructional information.
• There are a multitude of UAV Facebook groups for specific frame designs and manufacturers, including a wonderful group for female builders and pilots called the Amelia Droneharts.
• Maker Media has a phenomenal lineup of instructional publications including Make: magazine and the entire series of Getting Started books.
• We also invite you to share photos of your drone builds to our website’s gallery. We would love to see how you took the concepts in this book and ran with them. Use the incoming-only email address to send in pics of your multicopter builds: userbuilds@gettingstartedwithdrones.com

Thank You!

Speaking of the online drone community, we would like to say thank you to everyone from DIYDrones and MultiRotorForums who has shared any tidbit of information they learned the hard way, and was generous enough to share with us over the last almost six years. 

We must also thank a special group, our fellow flight-obsessed bunch who started out with us in a local Baltimore MeetUp group. They never fail to graciously contribute their time and talents toward our endeavors. They’ve kept us laughing too through all of the shaky takeoffs and hard landings.

We appreciate you: Brian Kraus, Chris Meaney, Tom Minnick, Ian Wollcock, Beresford Davis, and Elliot Greenwald (who was our awesome hand model)!

Finally, many warm thanks to you, the reader, who have made the investment in time, money, and effort to challenge yourself to get started with drones. Hope to see your builds in the gallery! We wish for you many years of learning and happy flying!