mike_kelly's blog View Details
Archive for February, 2019
Posted by mike_kelly | Feb 27, 2019 @ 12:27 AM | 10,311 Views

OlliW's new Pixhawk Cube carrier for UAVCAN. Very exciting.
Posted by mike_kelly | Feb 26, 2019 @ 01:29 PM | 10,598 Views
Amazing! I did not melt my ESCs into slag and they all work. Yippie!

One of the nice things about a UAVCAN ESC is it doesn't need to be calibrated like a standard PWM ESC. But you do need to configure the ESCs, each with a unique node ID, and set them up so they are in the right position on your frame.

To set the node ID we go into the UAVCAN GUI, click on the automatic Node ID server, and let it assign a random ID so we can see the node. Then we simply open each ESC node, click on "fetch all," and then change the node ID to whatever we want. Each node can have any ID up to 126. I am setting mine so they are 60, 61, 62, and 63 but it could be 34, 68, 92 and 101. You can choose any ID as long as each node has a unique number and it is not greater than 126. Be sure to click "save all" afterward to change the ID for each ESC.

There is an index to identify the ESCs. I have four ESCs so the count starts at 0 then 1, 2, 3, unlike the Ardupilot count that starts at 1. Each ESC needs to be associated with it's Arducopter arm/motor number. Don't be confused with Arducopters motor test which starts at the upper right and goes one motor at a time clockwise labelling each motor in turn A, B,C and D.

For Arducopter, my X frame (picture on the right), motor order is upper-right motor 1 then, going clockwise around the quad, lower-right is motor 4, lower-left motor is 2, and upper-left motor is 3.

We need to associate each ESC, where we have placed it on the...Continue Reading
Posted by mike_kelly | Feb 24, 2019 @ 04:22 PM | 10,703 Views

I hate doing ESCs. Because of my unexceptional soldering skills, I tend to melt them into a pile of slag. I'm going to try real hard not to do that today. I could use the general-purpose node and program it for ESC. It would have the advantage of being able to use one general-purpose node for all four of my ESCs. The ESC firmware supports up to 6 PWM or 4 Dshot outputs. Just a reminder that you can make all these UC4H devices with simple "Blue pill" STM boards that are really cheap. They may not be as neat and clean but it makes UC4H super accessible.

>>>> But I want to use the OlliW super-special Kiss ESC carriers. Super cool!

...Continue Reading
Posted by mike_kelly | Feb 23, 2019 @ 08:25 PM | 10,287 Views
Ok, I got the basic platform up and running. The UC4H Power module is powering the Pixhawk 2.1 Cube and the CANbus. I can connect to the Cube with Mission Planner and I have installed Betacopter 3.6.6 from OlliW Github respository. OlliW has provided pre-compiled versions for three standard flight controller FMUs. Use ArduCopter-v2.px4 for standard Pixhawk 1s and Cubes. Use ArduCopter-v3.px4 for Solo boards and ArduCopter-v4.px4 for newer boards like the Pixracer. You do this by going to the install firmware tab in Mission Planner and Load custom firmware. Loads just like any normal pre-compiled version of Arducopter.

Now we can have some fun. The SLCAN device is a basic tool for monitoring the CANbus. If you are a network type it is like an ethernet network sniffer. Think Wireshark or Bloodhound. It listens in on the bus and can capture the messages going by. You can make one or buy one from Jdrones or Zubax. The UAVCAN GUI tool gets this info and displays it for you. So get UAVCAN GUI from the UAVCAN.org site and install it.

Plug your SLCAN adapter into your computer via USB and a CANbus cable is plugged into one of the two CANbus ports and then to your CANBus. In the following picture you can see my SLCAN plugged into my computer and then to my CANbus expander.

On the CAN Interface Configuration screen choose the usb port your SLCAN is connected to. (You can unplug the SLCAN and run the UAVCAN GUI again and see what port disappears if you are unsure.) The...Continue Reading
Posted by mike_kelly | Feb 22, 2019 @ 01:07 PM | 10,233 Views

I have checked that the UC4H Powerbrick and the Power Distribution Board are connected correctly and working. The correct 5.3v is powering the CANBus. I am using JST-GH expanders made by MRO which he makes for I2C but work for the CANbus. The CANbus is not designed to be a STAR topology but a daisy chain. But given the short distances involved on the quad it just does not affect anything negatively and it is so much easier to use the expanders.

...Continue Reading
Posted by mike_kelly | Feb 21, 2019 @ 06:41 PM | 10,275 Views

I received all my UC4H modules from Jani at JDrones and some modules OlliW built for this project. Thanks, OlliW! I'll use a UC4H V2 Powerbrick to power the system. The Universal Modules for GPS, Serial Bridge, Mavlink Bridge, LED Notify and Display will finish off the system. I'll use OlliW's UC4H Kiss 32A ESC carriers but I could use Universal Modules for the ESCs also.

I suppose the place to start a new build is the power supply because everything depends on reliable clean power. One of the problem areas and points of confusion in APM/Pixhawk builds over the years has been supplying power. The flight controller is a flying computer with sensors. In order to operate it needs clean reliable power to stay working and to evaluate its sensors accurately. So you don't supply power to your flight controller from a BEC on your ESC. Those voltage converters were made for simple devices on airplanes, not the rigorous requirements of a flight controller. Also, we can't power everything in the whole world off our flight controller power module. So just don't do it. Use a separate voltage regulator for other devices that need significant power. A flight controller pulls a few hundred mils so don't think about powering a 1 amp 5v led strip with the flight controller's power module.

The next very important aspect of a flight controller power module is to be able to monitor the power we are using to estimate our available flight time. We would like to know as accurately as...Continue Reading