Newbie Help! , Need parts info for a quadcopter

Hi Tony,

Thank you for all the pics, i see that you have got a good amount of experience , this is i want to gain a good experience in design of making a drone and then understanding the software/hardware working together.

I am almost done with the ordering of the first set of components. Now need to wait until i get these.

My plan to to get started now and i am sure that i will run in to a lot of issues , for which i would come back here and ask all you kind people for some help.

Finally I have ordered the first set of components for starting the Drone project.

  • Some of the items from HobbyKing are backordered , Hence ordered these from Ebay.
  • Some of the items are avaliable in the international warehouse in Hobbyking , not sure what would be the import duty charges for ship to USA.
  • Battery zippy 2800mah ordered from eBay. http://www.ebay.com/itm/141597857900 , Hopefully this is good for a start.

Raspberry Pi 2 (ordered)

Navio+ and accessories (ordered)

FPV250LH Frame: (ordered)
http://www.hobbyking.com/hobbyking/store/_61388__FPV250LH_Low_Hung_Clean_and_Dirty_KIT.html?strSearch=250lh

Baby Beast V2 Motors, 12A ESC and CW/CCW prop adapters combo: (ordered)
http://www.hobbyking.com/hobbyking/store/__66977__MultiStar_Afro_Combo_Pack_2206_Baby_Beast_Motor_and_12A_Afro_ESC_Set_of_4_CW_CCW.html?strSearch=multistar%20combo

Pixhawk compatible PDB (built-in volt+amp sensor, fits perfectly in top/centre of FPV250): (ordered)
http://www.hobbyking.com/hobbyking/store/_68696__HK_Pilot_Power_VI_Module_Distribution_Board_And_Dual_UBEC_ALL_In_One_120A_and_10s_UK_Warehouse.html?strSearch=hk%20pilot

props : ordered from eBay , http://www.ebay.com/itm/231381935797

Battery : zippy 2800mah ordered from eBay. http://www.ebay.com/itm/141597857900

Battery charger: ordered from eBay , http://www.ebay.com/itm/131149071190

Power supply : ordered from eBay , http://www.ebay.com/itm/351396684565

cheap soldering gun: ordered from eBay, http://www.ebay.com/itm/360992748741

cheap soldering gun stand: ordered from eBay, http://www.ebay.com/itm/131483056320

soldering tin: ordered from eBay , http://www.ebay.com/itm/271819395250

extra struts: ordered from banggood, http://www.banggood.com/Diatone-M337mm-Aluminum-Standoff-8pcs-For-RC-Multirotors-p-973469.html

Pending items:

  • Radio control, Need to understand.
  • Female XT60 connectors.
  • Extra wires.
  • Connectors.

Hi Tony,

Finally i have received all the basic parts and have started to assemble the quad.

I finally ordered

  • Fr-Sky x8R and Taranis-Plus

Below are some of the questions i have:

  • I completed the PDB wiring as shown in your pic.

  • Hooked up the Afro ESC to the PDB

  • Hooked the power supply to PDB

  • I get a beep from the ESC with no LED , every second. ( is this normal ?)

  • When i hook up the a single ESC to X8R, bind it to Taranis-Plus , if throttle is applied , the motor works properly and i can see ESC green LED color, no beep are head when connected to X8R and led is Green.

  • Is it possible to hook all the ESC to X8R and upon throttle from Taranis-Plus , all the motors should spin (just as test)

  • Do we need to connect the motor wiring in such a way that 2 motors spin clockwise and 2 motors spin anti-clockwise?

  • I have not yet received Navio+ boards (already shipped), Do i need to connect the 4wire connector from PDB to Navio+ for power or do i need to use the Navio+ power supply cable?

  • Do you the pictures as how the connections form ESC and PDB are done to the Navio+ board?

Attached is the pic of my partial done setup…

Thanks in advance for all your help and guidance.

–Cheers,
Deepak

Looks good!

Beeping ESC is normal, it means “lights on but nobody at home” :slight_smile: If the props were on you might see them “twitch”, I think it does a few milliseconds of power to show the rotation. Same effect after a crash when APM disables itself for safety (something I learnt the hard way).

To power the Navio+ you use the supplied (in the PDB box) 6 wire “Pixhawk/APM” power cable from the small white “DF13” connector and plug this straight into the power connector of Navio+. Besides powering the flight controller it also sends voltage and amperage information (you don’t need that optional power/voltage cable from Emlid when you have this PDB, but if you’ve ordered it anyway you should find it useful for bench testing).

To power the receiver, you go via the servo rail. Leave ONE of the four ESC red wires connected. That means you MUST disconnect the other three. It’s all covered in detail in the Emlid docs link below. Note the tiny crosses X over three of the four ESC wires (a bit hard to see but the text clearly warns you about it):

http://docs.emlid.com/Navio-APM/hardware-setup-navio-plus/

By the way if you had OPTO ESCs (no BEC) you would take the 5v from the PDB down to the servo rail. So you have lots of options. Oh remember you need the FrSky SBUS to CPPM converter between your receiver and Navio+ because the X8R speaks the newer SBUS language which is not supported yet by the Navio+ drivers.

There are two calibration procedures you should do when you get the Navio+ and have everything connected:

  1. ESC calibration. Follow the APM:Copter docs for “all at once calibration” but read the Emlid docs/forum on how to do this by setting parameters instead of using the Pixhawk “arm switch” (which we don’t have on Navio+). Still easy, just a slightly different technique.

  2. Voltmeter calibration. As documented (with no changes) in APM:Copter web site, but take note that you have to generate about 10A of power before you’ll get an accurate ratio. And don’t worry about readings at low amps, none of the boards are accurate at low amps. That’s why you have to take the setting at about 10 amps.

On that subject there is one thing I forgot to add to the list. Everyone with a battery powered RC model should have a multimeter. I like this one from HobbyKing because it does all the combinations of reading voltages (battery balance lead checking, battery load/performance checking and more) plus it has nice features (at the same cheap price) like a servo tester and RPM meter.

http://www.hobbyking.com/hobbyking/store/_31499__Turnigy_8482_7in1_Mega_Meter_Battery_Checker_Watt_Meter_Servo_Tester_EU_Warehouse.html

The other thing which is useful when you are playing around the first time, is to have a beeper when the battery is low. Sure the built-in telemetry and other features are supposed to prevent that. But when you’re getting everything setup you’ll easily forget. Then your drone drops out the sky and your battery will have had a dangerously low voltage (not good for health/potential fire in extreme cases). So just get any one of these an hang it off the balance lead, secure it with velcro somewhere, e.g. back on top of the battery strap works well for me. This is the one I bought but there are others which also show the voltage which I’d probably get the next time:

http://www.hobbyking.com/hobbyking/store/_18987__HobbyKing_8482_Lipoly_Low_Voltage_Alarm_2s_4s.html

Finally to answer your other question, yes for testing you can easily get all the motors to spin. Just create a “mix” on your Taranis, which takes the throttle input and sends it out on all four channels of the receiver. You couldn’t fly with that as there would be no levelling. But it would help you test the prop rotation and ESCs.

p.s. one other part you need in the toolbox later is an ESC programmer. No worry because Hobby King always flash the ESCs to some recent SimonK build and in a combo box like you bought they should all be the same version. But later you might want to learn how to update your ESCs with this:

http://www.hobbyking.com/hobbyking/store/__39437__Afro_ESC_USB_Programming_Tool.html

p.p.s. The legs fall off that frame quite easily so what I do is loop the three motor power wires through them and cable tie. That way when they fall off they just dangle down (not lost in the grass).

Hi Tony,

I am able to figure out how to get all the 4 motors working using the taranis-plus , i needed to just do the proper settings in the Mixer settings, and i also figured out that we need to remove the middle power cable from the ESC and keep only one ESC middle power cable, Now i can get all the 4 motors to spin.

Do we need to connect the motor wiring in such a way that 2 motors spin clockwise and 2 motors spin anti-clockwise?

also i had questions regarding the mounting of the Raspperry pi2 + Navio board on the frame, so you have some special arrangements as a mounting plate?

also the low voltage checked for the battery , my battery is 3S, 11.1V and the one you mentioned in the link has a low voltage threshold of 3.3v per cell, i am wondering in a balanced charge mode , if each cell has 3.6V(as max i guess), so does the 3.3v per cell threshold seem bit too early to warn? or probably i am missing something here , Please correct me.

Cheers,
Deepak

##Motor Directions##
Yes the motors needs to be connected so they are turning in opposite directions as you go around the clock. It’s documented here:

http://copter.ardupilot.com/wiki/initial-setup/assembly-instructions/connect-escs-and-motors-pixhawk/

You have a Quad-X frame, so looking at the top with the drone pointing forwards away from you:
Channel 1 is top right and rotates Counter-ClockWise.
Channel 2 is diagonally opposite 1 at the bottom left also rotating CCW.
Channel 3 is to the left of channel 1 and rotates ClockWise.
Channel 4 is diagonally opposite 3 at the bottom right also rotation CW.

##Propeller Mounts (CW/CCW Adapters)##
Regarding your self-tightening prop adapters you got with the Multistart combo. You use the threads/caps with the opposite direction so they tighten as the motor moves. That is when a CW threaded adapter is on motor 1, it rotates CCW so the inertia/friction/torque of the motor pushing hard to rotate will make the cap nut force itself to tighten DOWN against the CW thread.

You can test this, hold the prop adapter top then rotate the outside of the motor in the direction it turns, the propeller should be tightened. It’s so easy and when you are used to them, you can just quickly spin them down to as tight as your hand can make without too much stress, then let them tighten themselves completely when you spin up the motors to take off. Worst case if you left them lose the props skid a bit until they are tight. but they will never come off.

##Mounting in Frame##
When you build the lower case of the Low-Hung FPV250, leave one set of those red support spacers out, the one in the middle offset towards the back is best, leaving the front bay separated for FPV equipment. There are slots along the sides, to start with use cable ties to mount the board. Later if you can get hold of a 3D printer or order a print online you could mount the Pi and Navio+ inside one of the custom cases posted here:

You could also use only the bottom half of any standard RasPi case if you want a stronger base. With any case it’s probably best to velcro it down as they don’t normally have fixing loops for cable ties. In the long run I’m thinking of modifying the base of the LH to make it fit aound the Navio+ (and even Pixhawk was a squeeze) without removing any spacers and with optional cable tie loops.

##Batteries##
Caution you need to know about Lipo safe voltage ranges. For each cell, it is 3.0v to 4.2v and below 3.3v is “dangerous”, below 3.0v “critical” meaning it may catch fire or explode. Hence the Lipo bags for storage and transportation. In fact your charger may refuse to work with batteries where any cell is below 3.3v (there is a trick to charge briefly up to 3.3v per cell as a NiMH but you’ve still taken some life out of it so want to avoid this). The normal level for the cells battery is 3.7v and the further below this you fly the more stress on the battery.

With a 3S (cell) battery we have the following tables to consider:

Cell Voltage Ranges
3.3v per cell empty (danger)
4.2v per cell full
= 0.9v range discharge (100%)
0.7v range used (80% rule) = warning land now!

3 Cell Battery Voltage Ranges
9.9v 0% empty (danger)
11.4v 20% empty (safe) = warning land now!
12.6v 100% full

It’s all explained here:

p.s. for the Hobby King PDB volt and amp sensor I used these values in the APM configuration:

ArduPilot Battery Settings
Voltage Divider 10.125635
Amps Per Volt @ ~10.86A = 20.5530

##Motor Mounts##
The M3 screws in the FPV250LH box are too long for the motors, they will touch the windings. Use a washer to space them back a bit. With the power off the motors should turn freely, just braked a bit by the magnets inside. If it’s stiff then you might have the screws too far in.

##Frame Legs##
To stop the legs falling off without using permanent glue, use something easier to remove like hot glue then mount the ESC wires around and through them like this:

Hi Tony,

Thank you for all the info and especially for the safety tips for handling the battery. I have ordered all the battery safety equipment and battery safe storage as well.

But its also mentioned that never expose the battery to direct sunlight , but if we fly the drone then its bound to get some direct sunlight , how do you tackle this, do you have some protective cover over the battery?
on ebay i see the below
http://www.ebay.com/itm/Lipo-Safe-Charging-Bag-Safety-Fireproof-Charging-Sack-/161594849714?pt=LH_DefaultDomain_3&hash=item259fcdb9b2
do you think its a good idea to use this cover and then mount the battery on the drone , of course this might add to the weight.

For the Mounting of the Navio+ i had seen the 3D design box , i have asked one of my friend who works in Product design to help with the 3D printing of the mounting box.

I now understand the Motors rotation configurations.

I can say that i am half way thru the drone assembling and i am still awaiting for more parts to arrive, i am sure that i will be having more questions as i approach my final assembly and software configurations.

Thanks again for all your kind help and tips.

Cheers,
Deepak

The battery is not so sensitive to sunlight during normal RC/hobby usage. I guess the point of the warnings you read about sunlight was for storage, like fuel or anything else sensitive to overheating. If you lived in a hot country and the sun was focused through a window in your garage for example, the battery could overheat and catch fire. None of the outside temperatures would cause concern, not unless you leave somewhere like Death Valley :slight_smile:

You have a Lipo safe so there is enough protection to start with, store it away from stuff which catches fire just in case. If a battery were to ignite the fireproof bag will contain the flames, but of course a lot of smoke and heat will be around the area until it burns out so you should position it somewhere sensible, or in something you don’t have to worry about (e.g. small garden shed which you could live without). Storing some sand with a shovel and a smothering fire extinguisher type would be super smart if you’re really worried about this. I guess a lot of people like me just stick the bag in a corner of a garage. I bought a metal tool case to put mine inside. I have a friend who uses an old ammunition storage box.

Drawing power from the battery also causes heat, but none of our tiny RC models will be overheating the battery though, not so long as we bought batteries with the correct C rating and don’t go beyond the burst rating when doing crazy flying. Anyway the quad is flying around in the air with four “fans” (propellers) right next to it so it would never overheat in the air. I imagine it could be important on industrial drones where many/larger batteries are packed inside would have to worry about battery cooling. Electrical faults and flying in rain would be exceptional cases of course. All of the advice I’ve heard about drones catching fire in the air was to do with ESC problems or power cables shorting across carbon fibre frames.

Best practice is just to check your batteries regularly and make sure you rotate their usage so you don’t forget to cycle them. I had one battery which was just left 1 day after 80% usage and one of the cells had already dropped dangerously low. I think this is because it’s left below the nominal 3.7 volts. The storage voltage is not fully charged by the way. Your charger probably has a storage mode, which will charge or discharge it down to a lower voltage than full (can’t remember the voltage but it’s probably something like the nominal voltage).

Regarding the landing gear , I plan to fix the low hung frame below the quad arms.(quad arms with motors on top, below is the low hung frame).

I plan to fit the battery and X8R receiver on the low hung frame, this configuration would provide a low clearance between the low hung frame and ground.

Do you have any suggestions for any other landing gear for such a configuration?, which can provide a good clearance between the low hung frame and ground.

also i see from your pics , you have labelled some wires as 12V and some as 5V, are these from the PDB?

currently i have connected all the output wires to below of the PDB and i suppose i am getting 5V output per motor.

Yes you have the right idea, the “low hung” is mounted below the arms. There is less than 1cm clearance. For that reason I 3D printed longer legs. Check-out my Thingiverse collections, I bookmarked almost all the useful stuff I could find on quadcopters into useful categories. There are enough people who have made legs and even complete replacement parts specifically for the FPV250 frame.

http://www.thingiverse.com/CodeChief/collections

And here is my remix of the landing gear, stretched to 8cm:

Normally the battery won’t fit inside the lower frame because you’d have FPV gear up front, flight controller in the middle and radios at the back. With the Navio+ and Raspberry Pi camera we have more room, but I still would not expect the battery to fit. You won’t have much clearance on top because of 6 inch props and even 5 inch props are close to the middle. I wouldn’t fit the Navio+ on top because the whole point of this frame is to vibration isolate the flight controller, it makes a big difference.

To mount the battery you have two options. First as I described before, use additional spacers to create a cage around the centre piece and put your battery in there. That is also good because you have a balanced vertical weight distribution. The other option is to use my extended landing gear or a helicopter skid (I think that is better in the long run) and mount the battery below.

p.s. I plan to do a load of alternate builds and document them together with the flying characteristics. I’d expect the performance to be just as good with the battery below but a bit longer to turn corners and lumpy doing rolls/acrobatics.

I see from your pics , you have labelled some wires as 12V and some as 5V, are these from the PDB?

currently i have connected all the output wires to below of the PDB and i suppose i am getting 5V output per motor.

Just want to make sure that i am not missing anything from the PDB side wiring.

On that drone I was using OPTO ESCs so had no BECs on the arms, which is why I used the 5V from the PDB. The 12V was necessary for my FPV transmitter. That drone is not the Emlid drone, it’s a Pixhawk drone, about 80% the same though. I’m hoping the lag on the wifi won’t be so bad, so I won’t need FPV equipment, then the 12V wouldn’t be used on the Navio+ drone.

As you have ESCs with BECs (non-OPTO) you have more than enough 5v outputs. I’m not sure though if the PDB output is cleaner, because it appears to have some small SMD ferrite cores on there (I presume the bigger cubes on either side are filters). Maybe somebody who is an expert at electronics could clarify. Hobby King documentation is always limited, even for their popular devices.I don’t think there will be much difference, especially with digital video (Pi Camera).

Anyway you have the option to try both sources as you have a good PDB. Then just remember to disconnect all the ESC power lines so there is only ever one 5v source active.

I was a bit delayed on the Linux wireless networking, a total pain. I’m trying to build a mesh network with multiple drones and the ground station all talking to each other without requiring a master. Once that is out the way (or I give-up on a mesh and use the GCS as an access point/hub) I’ll be completing all the documentation and tests.

Hi Tony,

Writing back after some time now , I finally received all the components and was busy setting up the quad.

I finally managed to setup it up entirerly , and i am able to ARM the ad from APM planner 2.0.
the SBUS to CPPM works fine and the throttle now starts the quad.

but the issue i see is that the qaud only has a lift of left had side and right hand side does not lift

  • is it because of weight issues in my quad?
  • do i need to calibrate the ESCs?

I am not sure what could be the case here, if you got any idea/info as how to debug this please share.

Thanks,
Deepak

Hi,

yes you should calibrate the ESCs, no matter if it is the reason for your problem or not.
If you built a conventional X or + quad, it would be hard to build it so much out of balance that one side would not lift.

  1. Check motor turning directions and motor connection order.
  2. Check your props, are they all mounted with the right side facing up?
  3. Check your ACC calibration in APMplanner, is the horizon level in the main flight screen? If the ACC is not calibrated correctly, it will try to reach what it thinks is level.
  4. Do not move the quad during startup of the software.

I hope you get your problem solved!

Hi,

I verified all of these, but still face the issue, i can see that the quad gets a lift that the back side , but the front side never lifts.

The front side is bit heavier that the back side, but its not that heavy.

  1. Check motor turning directions and motor connection order. ( Yes they are in correct order)

  2. Check your props, are they all mounted with the right side facing up? ( used 3 blade props, they are all facing properly)

  3. Check your ACC calibration in APMplanner, is the horizon level in the main flight screen? If the ACC is not calibrated correctly, it will try to reach what it thinks is level. ( ACC is calibrated properly, i can see in APM Planner animation that on ground level its horizontal.)

  4. Do not move the quad during startup of the software ( Tried this as well)

I had a couple of questions

  • I am using the stabilize flight mode ,i ARM the quad from the APM Planner , is there a way to ARM the quad using the radio controls, i see that that if we hold the throttle to down and rudder to left for 5 mins it should ARM and the motors should start spinning , is this the same for Navio+ as well?

  • are there any other methods to debug this issue ?

Thanks,
deepak

Arming is throttle down and rudder right. Disarm is down and left.
Did you calibrate the ESCs?
Check the channel out values for channel 1-4. Are they all increasing when you raise the throttle (props off or quad tied down) and are they more or less the same?
Are all motors turning freely?
Other things I can think of are electrical problems, like a broken cable connection or a cold solder joint.

Finally i got the drone to take off…

The issue: I had wrongly mounted 2 of the 3 blade props , which was hard to notice.

Well now the issue is behind me and the drone now hovers , but does not stand still in one place , this might require some more tuning.

Thank you all for all the inputs which helped me make my first drone assemble and take off.

as i work on to stabilize and make it more reliable , i would need more inputs.

Some of the other questions i had:

  • Are 2 Blade props more efficient that 3 blade props ?

I am glad it was a minor error.
The quad will not stay in one place in stabilize mode. Stabilize just keeps the quad level, or at the attitude commanded by the TX stick position.
It will always drift with external influences.
You get GPS assisted flight with loiter or poshold mode.
If it always drifts in one direction, there were two methods to tune level flight. I do not know if they are still valid in the latest APMcopter versions, because I did not use them for a while.
The first way to do it, was to hold the arming sequence for 15sec untill the LEDs startet to flash red blue continously. Then you must lift off and fly in one place with as little movement as posibble for 30sec. Land and disarm. The correction values will be saved. During the next flight, hover should be more stable. This is the method I used. For the other method you have to assign a function to CH6 and trim the copter with the TX trim buttons. I can not remember the procedure, I never really used it.

Yes 2 bladed props are more efficient then 3 bladed props. But to get the desired thrust with a limited maximum diameter, like on a miniquad, you have to add blades or blade pitch. Pitch only works to a certain point and you want as little blade pitch as possible on a multirotor.
Some peoplle also prefer 3 bladed props, because they cause a higher frequency vibration compared to two blades. The higher frequency is less prone to cause the jello effect in cmos camera sensors.

Happy flying!