"Sally"A fully autonomous quad under 255 grams, programmed with a cellphone over bluetooth.
2-1-16: Systems integration. Thinking a third deck might provide the real estate for the bluetooth board. There's enough room, and it might protect the flight controller. Painted liquid tape on the radio, bluetooth, flight controller, esc to motor connections, and power busses on the PDB. Have to get more 5mm nylon standoffs for the third deck, which is made of scrap plastic just like "Marcie" and "Lucy".
Have to admit that my enthusiasm has faded a lot since the hobby was equated with terrorism. Imagine having to register as a sex offender because you have a penis. We are outcasts among other radio control hobbiests, and personna non gratta at fields we used to fly at. Everyone I know is flying in "secret" locations, some in the dead of night. All the RC hobby shops are going broke. None of these laws will prevent any hostile or dangerous activity using radio controlled aircraft, just as ever stricter gun control laws have no effect on gun violence, and auto registration and licensing have no effect on the 40,000 fatalities every year. Perhaps I'll drop little flying toys, and look at larger, more interesting robotics, until a hysterical public demands "something be done" about that too. But it's already too late. They're running everything already, and we can't live without them.
1-23-16: Working on the sub-assemblies. Removed all but the 4 esc pins on the Pixhawk. Also removed pins on the Bluetooth and OrangeRX radio, after binding the radio to the Walkera Devo-10 transmitter. Mounted the GPS unit on the top plate with the tape it came with. The radio will hang out the back just like "Marcie", but it's a smaller radio. Thought about mounting it atop the flight controller, but concerned about heat. This is the same radio used on "Lucy", I stick with what works. In this case the radio doesn't need much range, if she's flying "missions" independently. I've seen videos where the aircraft flies out of radio range just fine. Plan is to integrate the bluetooth board into the GPS connector, and use the second telemetry (serial) port for the OSD. I'm going to try using the regulators on the CCC3D power distribution board for the video system. With three different voltages involved flying a separate video battery is more difficult. Why did I switch video transmitters, when my usual model works so well? Because someone gave me a gift card for Christmas that won't work in China so I ordered this one from a US source, at twice the price.
The notes are for the GPS cable rewire. The tick marks are empty holes, which the bluetooth board will use.
1-23-16: This is the shakiest build I've ever tried. I really don't know if I can get away with this one. Most of the parts are in so I got busy using the familiar Diatone ET 150 frame. The side standoffs block ports I need. And the pins on the Pixhawk Mini hit the back standoffs, so I cut some off. I want to use the ESC connectors, at least at first, so I can program the ESC's. I installed the motors and ESCs and tested with a servo tester. Then I put the Pixhawk back on just to see. Removed Pixhawk and connected to Mission Planner, it's config program. Seems to be OK. Plugged the GPS in, should have measured voltages first. Pinout is REVERSED on the Pixhawk lite. No damage done, gets 9 sats indoors.
1-12-16: Tonight was motor test night. Below are the inductance tests, performed with the little unit on Ebay. These motors from MYRCMART.COM averaged closer than Marcie's. After that each was test-run with a 40 amp esc connected to a bench power supply and a servo tester. Each sounded fine, and nothing exploded. For a change. Still waiting on the Pixhawk mini flight controller, a Diatone ET 150 frame, a better power distribution board, and another camera. Already have lots of batteries and rotors. Just like "Marcie", I want the top plate to be easily removable for modifications. Except for the GPS / compass, everything will be on the bottom deck.
1-11-16: Crap! Wired up the video system, blew out all but the transmitter. Turns out I wired the voltage regulator backwards. Total damages: about $25. (Back) ordered replacement cameras from BANGGOOD.COM. Uploaded backup image to another Micro MinimOSD. Tested another step-down voltage regulator, this one outputs 3.3 volts, for the replacement camera. Learned how to program ESC's with BLHeli and a USB stick. Turns out you must connect power to the ESC. Looking into using SimonK. Next up: motor testing.
1-10-16: Tested the HC-06 Bluetooth uart, which was much harder than expected. Finally got it obeying commands from the arduino programmer over the FTDI, changed it's name to Sally, changed speed to 115,200 bps, and changed the pin. It's connected just like everything else, with power, ground and tx / rx reversed. The FTDI was set to 5 volts. It defaults to 9600 baud. Getting the phone to bind was no problem, but getting stuff to appear on the (Linux) computer was another matter. Ended up using GTKterm, using /dev/ttyusb0, at 9600 8,n,1. On the phone I'm using "bluetooth terminal", an Android app. But nothing I typed on the computer appeared on the phone. The Arduino IDE program sends it AT commands OK, provided the phone is NOT connected or paired with it. Without the Pixhawk I can't tell if the "Droidplanner" app will actually talk with it. At least I haven't blown it up yet.
1-7-16: Looking for something to do while I wait for parts. Decided to make another video system bracket like "Marcie's", but since every gram is a big deal, thought I might lighten it with some holes, like hot rodders used to do with their frames. This aluminum angle material makes the video system self-contained and easily removable. Maybe I can add an adjustable camera angle also. Weight is 3.3 grams. I use 3M Dual Lock (up-scale velcro) to attach removable stuff like this to the frame. It was a tiny little project, but now I can build and test the video system. And it keeps me off the streets.
1-6-16: Ordered Pixhawk lite ($62), a CC3D 5 and 12v PDB (four bucks), and another Diatone ET 150 frame ($20) from BANGGOOD.COM. May end up using the Diatone frame instead.
1-5-16: Ordered RCX 1604 3100 motors, 20a little bee ESC's, a programmer for the ESC's, a GPS / compass for the Pixhawk, and some power filters from MYRCMART.COM. These are the same motors used on "Marcie" and they work very well. Tinkering with the ESC's will be new for me. Continuing to wonder about this frame. If the battery is mounted in the frame as they suggest, an impact could drive it into the electronics, or the nylocks, which might set it off.
1-3-16: Trying to figure out how to lay out the electronics. It's a nightmare. The flight controller wants to be in the center of gravity, but it can't be. The antenna holes, fore and aft, block the camera aperture. So the video transmitter must be mounted at the opposite end, running long wires past the batteries and ESC's to pick up lots of noise. There is no good place to mount the ESC's, the decks are both too narrow, so I'll have to use lower powered controllers. Mounting them on the arms would present even more area to the wind, so I want to mount them on the lower deck. Mounting them atop each other would overheat them. The battery also generates noise. You can't mount it below because the gear don't extend down beyond the bottom plate. Mounting it inside the frame as advertised puts it closer to the flight controller and video system. I don't like mounting it atop the upper plate, because it makes the unit top-heavy. But it's the only place left. At least initially I want to leave the aluminum landing gear struts in place for torsional strength. If I put the battery underneath I may cut the landing gear off since it's just dead weight. None of the bulkheads can be moved or removed, because they support the motor mounts. To mount the VTX close to the camera and OSD I may drill another antenna hole just behind the first bulkhead.Want to keep all the sensitive electronics at the opposite end from the power systems.
Link to YouTube video of torture test HERE
1-2-16: Frame kit found in PO box today! Took about half an hour to put it together. No instructions are needed or provided, however it takes some juggling to assemble. It's held together with small hex screws and nylon lock nuts. All the hardware is the same size, so no sorting, and there were a few spares in case something ends up in the carpet. All the plates are 1.5mm thick. The top and bottom deck are 24mm wide. The arm width at the thinnest section is 9mm wide. I use a cheap plastic caliper so I can't be exact. The weight as completely built was 55.8 grams for mine. Moka's site advertises a lighter weight "without hardware", do they mean glued together with CA (superglue)? It didn't come with any, but will need some spacers when mounting PC boards on the bulkheads. The nylocks stick out about 2.5mm on each side of the bulkhead. I'm concerned about the little carbon fiber shoulders that the nuts secure to. How much stress can they take during a collision? They're not repairable. The front and rear bulkheads are 20mm apart. The "antenna" holes are all 7mm. There are slots for nylon ties and battery straps everywhere. Not sure I want to put the battery in the frame, was hoping the landing gear was long enought to protect a battery underneath.Looking at the nose, there isn't a slotted area to angle the camera. Turns out I can mount the Mini Pixhawk vertically on the bulkhead. In order to meet my weight budget I may have to eliminate the video battery.
1-1-16: Had a gift card that wouldn't work overseas, so ordered a TS5823 200mw 5.8 ghz video transmitter from gothelirc.com in Chandler AZ, for about $23 bucks. It's got a -reverse- SMA connector I can use to mount it in the frame, and a tiny dipswitch for (32 channel) frequency selection. I already had a perfect antenna for it, on a Boscam Vtx that came with "Christine". Last night I ordered a Apm2.5/2.6/2.8 Pixhawk PIX 2.43 Bluetooth Module Bluetooth Data Link(For APM) from Persue Remarkable on Amazon. I'm hoping this will let me program the Pixhawk mini with my Android phone running Droidplanner or some other app. Would use the same Orange RX R615X 2.4 Ghx dsm2 to ppm radio (from Hobby King) for manual control with the Devo-10 / Deviation that "Lucy" uses. To run the motors I have some Afro 20a mini ESC's in stock. These have BEC's that I may use to power the flight controller and other stuff. I've got a Micro MinimOSD ready, but the Pixhawk might have an OSD built in. Still have to order the Pixhawk mini flight controller and 1306 motors. As with "Marcie", the plan is to test each component separately before assembly, including the donated frame.
To test the frame I'll attach the same weight that it flies with (450 grams) and "fly" it into a wall and pole by attaching a string tied to the top of the obstacle. I'll mount my phone where it can watch the collision and drop it from various heights to see if it's as tough as Moka thinks it is. I really like the airflow through the arms, but I'm worried about all the pieces, the flat / thin surfaces on the leading edges, and the vertical mounting of all the electronics. I'm not sure yet if Pixhawk can be mounted that way. In the video I commented on the motors have 4" rotors, but on the website it says the frame uses 3" rotors. This frame doesn't come with any power distribution board, but I've got some poloulu regulator boards and several generic PDB's in stock. If the frame brakes in testing I'll use a Diatone instead.