For an engineering project for high school, I have chosen to build an automated delivery drone, capable of carrying 1 kg of cargo, in addition to the dropping system we are going to build.
I need help optimizing this build for flight time, flight range, durability, and low cost (under $300 at most).
I think the props need to be large, and motors at low kv, for decreased power draw as a trade off for maneuverability. However, I know little of how to select motors and props and I know there is a lot of complex factors in that choice. This is where I need the most guidance.
I envision a quadcopter being a good choice, but it does not need to be a quadcopter.
As for a transmitter, I will be buying a cheap one, if at all. The drone will be automated, so a controller will only be needed for the initial testing phase and will not be as important once it is up and flying.
Heres my hobby king shopping list:
Quantity Stock Product description Price Weight
4 OK 171000436-0 - NTM Prop Drive 28-30 800KV / 270W Brushl.. $60.20 320
3 OK 017000065 - 12x4.5 SF Props 2pc Standard Rotation/2 .. $13.08 240
5 OK HKz30A - HobbyKing 30A BlueSeries Brushless Speed.. $55.30 235
1 OK HKz-Prog - HobbyKing Programming card for BlueSerie.. $3.28 17
1 OK HK-T6A-M1 - Hobby King 2.4Ghz 6Ch Tx & Rx V2 (Mode 1.. $25.06 998
1 OK FS-L001 - Hobby King 2.4Ghz 6Ch Tx USB Cable $2.85 60
1 OK 015000095 - XT60 to 4 X 3.5mm bullet Multistar ESC P.. $3.36 34
4 OK SHT007 - NTM Prop Drive 2830 Series Replacement Shaft $3.28 52
4 OK NTM28-ACC - NTM Prop Drive 28 Series Accessory Pack $7.40 88
TOTAL: $173.81 2044g
Sky Tools 127 Piece Heat Shrink Tubing Assortment $6.99 1
Vktech 40x 3.5mm Gold-plated Bullet Banana Plug Connector RC Battery $3.99 1
SunFouder 2 pcs Ultrasonic Module HC-SR04 Distance Sensor $8.99 1
NEEWER® Useful HJ MWC X-Mode Alien Multicopter Quadcopter Frame Kit Red/White $16.99 1
Hobbypower Top Pin APM2.6 External Compass APM Flight Controller w/ UBLOX NEO-6M GPS $69.89 1
FTDI Cable 5V VCC-3.3V I/O $17.95 1
Hobbypower Power Module V1.0 for Pixhawk Apm2.5 Apm2.6 Ardupilot Mega Flight Controller $11.101
Neewer Servo Tester CCPM Consistency Master Checker 3CH 4.8-6V $6.95 1
Subtotal (8 items): $142.85
I am going to use a VEX robotics motor to drive the dropping mechanism, they are
reliable geared motors and it will cost me nothing. I will wire voltage from the battery and
servo signal from the APM, they never draw more that 5A so it shouldn't affect anything.
FTDI cable is to set baud rate and name of bluetooth module (JY-MCU slave)
-Can the APM 2.6 take serial input coordinates and route to them? (I am willing to code it myself)
I already have a battery and charger, so that saves ~$60
The Turnigy nano-tech 4500mah 3S 25~50C Lipo Pack is what I already have, and seems like a good choice to maximize flight time to increase delivery range, but is pretty heavy.
I have a mix bag of those little plug wires, and 3 wire ones at the school I can use.
The distance sensors are for collision avoidance, is there any reason not to use those?
-Can I add code to stop and rotate until it is clear of obstruction? We do that in vex with robots, any reason this would be hard on APM?
The frame is inexpensive, if it does break, then we will build a H frame, but I want something to start with.
(also it looks cooler than any welded aluminum frame I could make)
Anything I can cut cost on? $316 subtotal + ~$40 for hobbyking shipping (yikes!) is within the budget.
Anything I forgot?
Thank you for reading my post, if you have any knowledge that can help me succeed in this project, I would love to hear from you.
I agree having a smaller size would be better, what size would you recommend for carrying one kilogram one kilometer away, dropping it, then flying back unburdened, and costing ~$300 to $400?
Do you know if any cheaper flight controllers than the APM 2.6 could support multiple waypoints and low level programmability? We need to fly to GPS coordinate, turn a servo, fly to another, turn a servo, then fly back to home. APM can do that for sure, but at nearly $300, it's way out of budget.
Before we start, how about you tell us a few details:
1. What is the targeted flight time?
2. What is the targeted range?
3. How is the drop mechanism mounted? Rails or hard mount?
Essentially, suggest you work downwards from an objective-oriented approach. Let us know the objectives and we can give some suggestions.
For electronics, all you need is an apm, a gps, a 5v reg, and data radio set. Forget the sonar they are next to useless. Invest in a better gps for higher accuracy if you wish.
The rest are extras you don't need. Even the bullets. Solder your connections.
I'll come up with a list next.
I did feel like I had come up with a lot of unnecessary parts but I wasn't sure what to strip.
The frame was also something I had trouble finding, I was trying to minimize radius but I realize that is probably pointless.
Thank you for all the help, the judges at our pre-project presentation seemed to think we were going to fail, most of the projects at my school are far simpler. I was worried that the constraints we had set were too hard for the budget, I'm glad to hear that they are doable.
I can't wait to see the list.
We have to do a lot of data collection on our projects, so I'll contribute all of our data here, and I'll get a copy of the presentation after we present in March.
Going by this the target, you'll need to build a quad that can fly for about 8min, carry 1kg load for the first 3 min, then fly back. Let me work out some calculations and get back to you in this thread.
Thank you for the insight!
-Our minimum range is one kilometer.
-We need enough flight time to make it that far comfortably, but I don't know what ground speed to expect.
-The drop mechanism is a motor with a hook, bolted to the frame. A box with a metal eyelet is held by the hook, when the motor rotates, the hook slides out of the eyelet and drops the box. The motor we have weighs 60 grams.
What I need help with: build a drone that can fly 1 km, and back, using coordinates and a gps, and perform a dropping action at the coordinate.
What frame size is best for this?
What kind of motor and props will be most efficient for this?
What size battery?
Is the APM2.6 and UBLOX gps a good controller for this objective?
I have not built a drone before, and I understand this is not a good build to start with, but it's definitely feasible.