My RunCam HD died after 5 months in a drawer. Reason: battery destroyed. It had enough energy for approx. 2 seconds of operation. So I had a choice: buy original battery from RunCam for $9.99 plus shipment, or fix it DIY style. I’ve choces the second option.
Luckily for us, RunCam used generic 803035 LiPo 1S, 3,7V battery that can be purchased in specialized stores. I’ve paid around $6 for mine, but if you look hard enough, you should find something even cheaper. Also, luckily (or not) there is a battery plug: 2 pin JST 1.25mm.
Miniquads are fun, right? After all, there is a reasons most uf us flies 210-250 quadcopters. If so, small flying wings should be fun too! I tried that already in late 2015 and failed miserably! My design did not survived maiden flight. Well, things like that happens from time to time, so few months ago, after learning few new things, I’ve made a second attempt. And this time I’ve succeeded.
This post is only a short update for SmartPort inverter for F4 flight controllers. Here is alternative SmartPort inverter circuit using bipolar BC547 instead of unipolar 2N7000. All other aspects of operations are the same like in MOSFET version.
Hardware SmartPort Inverter using BC547 bipolar transistors was last modified: February 4th, 2017 by Dziku
It’s still middle of winter here in northern hemisphere, but I’m slowly preparing for next flying season. One of my goals is to push my DIY HC-12 Telelemetry System to a next level. In both range and quality. For quality I’m planning small hardware LTM decoder with LCD. For range, I want to reach at least 1.5km with 9600bps FU3 mode and 2.5km with 1200bps FU4 mode.
While STM32F4 family processors installed in newest flight controllers are superior to STM32F3 (and F1 of course) in terms of raw speed, they are inferior to F3 family in terms of IO handling capabilities. For example, F4 family is not equipped with UART port inverters. And that creates a series of problems when it comes to connecting various serial RX receivers and telemetry systems.
The most popular FrSky (Futaba) S.Bus serial RX protocol and FrSky SmartPort telemetry require inverted UART signal. If there is no hardware inverter on hardware UART port, they will not work. While S.Bus requires only one data line, external inverter is not a big issue. Some time ago I’ve published The Simplest Harware Inverter. One MOSFET transistor, one resistor and that’s all.
In case of SmartPort, it’s slightly more complicated. Not only signal is inverted, SmartPort also combines TX and RX UART line into single wire. That means the following:
More complicated inverter is required
Software has to support this case and fallback to unidirectional UART mode
Flying season 2016 is slowly coming to an end on northern hemisphere. That means less time spent on an airfield and more time spent behind a desk. For this autumn I've found a very interesting, small project: Dualcopter.
Dualcopter is an UAV with two coaxial contra-rotating propellers and 2 control surfaces driven by servos. Lift and yaw are controlled by propellers, while pitch and roll by ailerons placed below motors. This video illustrates how it looks like:
My Dualcopter will be slightly different. Instead of foam and wood I will use 3D printed parts connected together CA glue and zip ties. Maybe it will not be super strong and probably will not survive any crash, but should be enough to make it fly for a minute or so. Almost all parts would be either 3D printed or taken from spare box. I'm not planning any new purchases.
Motors: Turnigy MT2213 935KV
Props: APC 1045 MR
ESC: Afro 20A
FC: Flip32 probably with INAV inside
Battery: 1300mAh 3S
Weight: around 800g with battery
So far, after 2 evenings I have this:
Two motors mounted on a frame.
Next step would be to build bottom section with ailerons and battery compartment.
Project Dualcopter – worklog #1 was last modified: September 30th, 2016 by Dziku
For the last few week I’ve been little busy building my next fixed wing UAV: “Marabou Stork” Depron/Carbon/3D Printed airplane with pusher prop build for FPV. It’s improved version of “Red Cruiser” model from last year.
It’s equipped with KFm-2 wing, Turnigy D2826-6 2200KV motor, APC-E 7×4″ propeller, 2700mAh Lipo battery, FPV setup with MinimOSD and RunCam PZ0420H camera. And Flip32 running INAV for stabilization and navigation (no GPS yet).
As you can see on a video above, it flies. Even pretty well. It needs some tuning, but have big potential. Unfortunately elevator malfunction grounded it after few minutes in the air.
Marabou Stork: FPV airplane maiden flight was last modified: September 16th, 2016 by Dziku
Beitian BN-880 (I’ve bought mine from Banggood) is an excellent, cheap and accurate Ublox NEO-M8N GPS module. I’m using it for last few months and I’m very happy with it. But is has one serious flaw: there are no cases/enclosures for it. So, in most applications it is naked. I’ve decided to fix that and designed 3D printed Beitian BN-880 case.