Tag: DIY
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How to make 868MHz or 915MHz dipole antennas for FrSky R9 or TBS Crossfire receivers
The correct length of 868/915MHz antennas used by FrSky R9 and TBS Crossfire is: From time to time FrSky has a big problem with cutting their antennas to a correct length. Good thing, you can make your own TBS Crossfire RX antennas for cheap!
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Do It Yourself liquid soldering flux
Do you know you can make your own liquid soldering flux? And possibly flux pen refill for cheap? All you need is some solid soldering rosin and 95% ethanol alcohol. Cheap, kind of dirty, but works…
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ESP8266 ESP-01 Low Power Mode – run it for months
Amazing ESP8266 ESP-01 WiFi boards have pretty irritating problem: theirs power consumption is pretty high. Minimal power consumption of about 70mA when doing nothing and above 100mA when when transferring data makes it rather impossible to use it on battery power for a longer period of time. Set of 2 AA batteries would be drained…
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SmartPort inverter for F4 flight controllers
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. There is an S.BUS inverter, but not a SmartPort inverter.…
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Hobbyking Mini DLG Pro 990mm durability fix
Entry level DLG (Discus Launch Glider) from HobbyKing has a quite important flaw for a “entry” level model: it is not durable. As a matter of fact, it is quite fragile, specially where plastic nose section is attached to composite fuselage tube. It is attached only with 3 small screws, and I can guarantee: every…
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DIY wireless telemetry link for UAV
Telemetry link between UAV (drone, airplane, boat) and laptop/mobile/ground station device can be very useful. Not only to get current drone position, altitude or battery level, but also, when wireless link provides such a possibility, to update drone parameters in-flight. Some radio links, like OpenLRS provides such a possibility out of the box. They include…
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Magical LiPo tree
Since LiPo batteries are potentially dangerous, they can not be just put into garbage. They have to be properly handled, utilized, before they can be safely thrown out. I will write more on this topic later. Here is only a picture of my magical LiPo tree. Knife, electrical connector, 12V halogen lightbulb, some sand, a flowerpot…
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Raspberry Pi: reset external I2C devices (not only I2C)
Electronic, and specially computerized, devices likes to hang from time to time. There are many reasons: software bug, hardware error, voltage drop, interference, too long wire, random incident. I’ve learned this hard way during work on my Raspberry Pi based weather station. From time to time external DTH22 temperature/humidity sensor refused to work. Only solution…
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Raspberry Pi + MOSFET = High power switch
With all the possibilities, Raspberry Pi requires additional hardware to turn on and off any additional hardware. GPIOs built in power limit is low: 3.3V, 16mA per GPIO, but not more that 50mA total). And while it might be enough to light a small LED, it is not enough for anything else. Forget about motors,…