Time to build a Baby Tricopter. This is a 170mm motor to motor crazy 7:1 thrust to weight ratio beast of a tricopter. It’s small and durable and a real blast to fly. So lets get started.
Before we start mounting stuff, I highly recommend finishing off the carbon fiber in the kit. There is a crescent shaped diamond file included in the kit for this purpose. File the edges lightly. Wear breathing protection and be outside when doing this. Carbon fiber dust in pretty nasty stuff.
The reason why you should do this is mainly that the edges become smoother (duh), this keeps zip ties from snapping prematurely, tape wrapped around things last longer, battery/camera straps lasting much longer and recedes the chance of you cutting yourself when handling the copter.
Now we can mount the BabyPDB using the 10mm long nylon screws, fiber washers and standoffs.
The fiber washers are there to keep the BabyPDB from touching the frame. There is no exposed pads or anything on the bottom so it should be fine touching the carbon, but better be safe than sorry.
You’ll be needing a pigtail with the battery connector you plan on using. I’m using the 5cm XT60 pigtail, which I stripped back a bit to get more surface contact on the pads.
Screw the nylon standoffs down to hold the board in place.
The wire on the BMS210 feedback servo is quite a bit too long, so we’re going to steal a piece to use to connect the PDB to the flight controller.
Solder the wires to the correct pads on the flight controller. The pads are quite clearly marked.
If you plan on powering anything power hungry through the flight controller I recommend moving this resistor over to the “BEC” position. This will bypass the built in 5V regulator on the flight controller. Instead the BEC voltage will power the board and all pads marked “5V” will output the BEC voltage.
Strap down the servo. You’ll be needing 2 zip-ties connected together to reach all the way around the servo. This also gives better strap down force as you have 2 places to apply force. Again alternate the “knots” not to get all force on one side. The groves for the tilt block extend backwards which will let you slide the servo back later when doing the servo alignment.
Baby tricopter electronics kit include thick black heat shrink lined with a kind of hot glue. When shrunk the hot glue melts and if you squeeze the edges properly when the heat shrink is still hot, the ESC’s will be water resistant and very durable.
To screw down the motors use the included 6mm long screws. If you use longer screws you might damage the motor windings and smoke your motor and ESC. Always use blue locktite when screwing anything metal into metal.
This is so that there is plenty of slack in the wire to allow for smooth, unhindered moment throughout the whole servo range. You can also see in the picture why we soldered the wire at an angle. Things get tight otherwise.
The back ESC should be soldered to the back ESC pads. Do not solder the ESC wires to the battery connector pads as this will bypass the current sensor and your current draw and mAh draw will be off by around 33%.
To protect the receiver I’m going to use some liquid electrical tape. It’s fantastic stuff which makes stuff water resistant and creates a rubbery kind of coating. If you plan on using it I highly recommend testing that the receiver works properly before putting the stuff on. It’s a real pain to get off. It’s also a good idea to take a picture of the top and bottom side of the board just in case something doesn’t work, you can go back and inspect your work.
The reason why I’m using the X4R is that I had one laying around. If I would built another copter I would use the XSR receiver, which is smaller and lighter and fits in the stack without modification.
While we have good access to the power pins we might as well solder in the FPV system. I’m using a HS1177 camera and a Eachine TS5840 with a 90° antenna connector mounted on this build. Not super happy with this video transmitter though. Will probably switch it for a TBS Unify pro HV, which is a much better quality.
Soldered the signal wire between the camera and video transmitter.
I’ll be powering the camera via the 6V BEC on the BabyPDB. This will take load of the built in 5V regulator on the video transmitter, which will keep the video transmitter a lot cooler. The BabyPDB BEC also has a cleaner output as well as it protects the camera from voltage spikes. The video transmitter I’ll be powering straight from the flight battery.
I soldered the video TX + to the VBAT pad. The – to GND, the camera + to the BEC+ pad and the camera – to GND.
Schematic. The reason why I don’t power the video transmitter from the built in BEC on the BabyPDB is that the minimum operating voltage on the videoTX is 7V. If you have a VTX that can handle 6V I recommend powering it from the BEC as it will significantly reduce the heat generated in the VTX.
It’s a great idea to have a beeper hooked up to your flight controller. This will greatly help when doing the tail tune and it will also help you find your copter when you crash it in tall grass and such.
I bent the – pin of the beeper to 90° at the base and then 90° again further down to be able to reach the pads.
Now we can start soldering signal wires to the board. The red and brown servo wires are connected to the pins on the edge labeled BEC + and GND. This will power the servo with the 6V from the babyPDB.
The orange servo wire is soldered to the pad labeled number 2 and the yellow to the “FB” pad. If you’re using a servo that doesn’t have a servo feedback wire you only need to solder the servo signal wire to the “2” pad.
Now the ESC wires. This is the way the signal wires should be connected:
Pad number 1 = Tail motor
Pad number 2 = Servo
Pad number 3 = Front Right motor
Pad number 4 = Front Left motor
Time to connect the receiver. I connected my receiver in the following way; – to -, + to +, SBUS output to R3 (RX pin on UART3) and SPORT to T2 (TX pin on UART2). Also mount the nylon standoffs at this point.
Mounting the camera is really simple. The bracket that is included with cameras such as the HS1177 and the Runcam Swift fit into the milled down grove. This grove prevents the mount from turning and holds it firmly in place.
Use a 6mm screw to mount it. If you’re using a Runcam swift use the 2mm screws that comes with it to mount it. You might need to file slightly on the HS1177 bracket as the manufacturing tolerances on those brackets are far from perfect.
Congratulations! The build is now done! Don’t forget to load the firmware onto the board and do all the setup. This process is the exact same as on the Tricopter V4 and Mini Tricopter, so you can look on the setup videos for either and set this thing up without any problem.
This is one crazy fast and super agile tricopter. I really look forward to seeing your builds and FPV videos! Please post them in this section of the forums. Good luck with your build!