Powering the TS100 Soldering Iron Using a 18 V Power Tool Battery

The portable, STM32-powered TS100 soldering iron has a wide input voltage range from 12 V to 24 V. Since the resistance of the soldering tips doesn’t change, the power consumption will vary from about 17 W at 12 V to about 65 W at 24 V. To power the iron from a Lithium polymer (LiPo)…

4WD Steering Using a Servo Reverser (or not)

Some RC cars or model kits allow to add the steering of a second (mostly rear) axis, using a second servo. This is, for example, true for the Tamiya CR-01 or G6-01 chassis. Tamiya recommends using a remote control system and an additional channel to set this up. If you don’t already own such a…

Using High Voltage (HV) Servos on Your RC Car

Regular “low voltage” servos In most(?) or at least many cases, your steering servo is only connected to your receiver, which is powered by the inbuilt BEC of your ESC.These Battery Eliminator Circuits (BECs) are basically voltage regulators that converts your battery voltage to a voltage of about 5 to 6 Volt. Connecting the servos…

Pixhawk Clones – Selecting ArduPilot Copter Firmware

Backstory There are different (flight) controllers available that are named “Pixhawk”, but in this article, I want to concentrate on the mostly Chinese “clones”. Although “clone” is the wrong term here, since the whole Pixhawk platform is an open hardware project. So building and selling hardware of this design is perfectly legal (which doesn’t mean…

Simple MOSFET LED Switch for Pixhawk

The Pixhawk flight controller, using the ArduPilot Copter firmware, allows for switching one or more AUX pins as GPIO pins from low to high (or vice versa) using the provided “Relay” function. Unfortunately the STM32 MCU of the Pixhawk uses a 3.3 V logic voltage on the white/yellow signal wire, which means that most regular…

Sonoff S26 EEPROM Upgrade

The Sonoff S26 WiFi-Plug/Switch uses a ESP8266 micro-controller and 1 MB of memory for its firmware. It is possible to replace the default EEPROM IC with a bigger one. This comes in handy, when using Tasmota and OTA-upgrades, since the upgrade needs to be locally stored, before it can be installed. The 32 Mbit (4…

Building wooden cases for the Ruideng DPS power supplies.

The “DPS” series of power supplies from the Chinese manufacturer Ruideng is popular among hobbyists. It allows to set voltage and current, but still needs a source power supply – so basically it’s a DC buck converter. It also doesn’t come with a case. I built three cases, using some scraps of plywood. Two cases…

STM32 T12-Lötstation

Wie bereits im einführenden Artikel beschrieben, handelt es sich bei dieser recht kompakten Lötstation, um eines von zwei verbreiteten Modellen. Dieses hier arbeitet mit einem STM32 Microcontroller und hat etwas mehr Funktionen als das Modell mit STC Microcontroller. Insbesondere besitzt sie ein aufwändigeres Display welches mehr Informationen liefert. Weiterhin kann man verschiedene Lötspitzen kalibrieren und…

STC T12-Lötstation

Wie bereits im einführenden Artikel beschrieben, handelt es sich bei dieser recht kompakten Lötstation um eine von zwei verbreiteteren Modellen. Dieses hier arbeitet mit einem STC Microcontroller und hat etwas weniger Funktionen als das Modell mit STM32 Microcontroller. Dies kann aber ggf. auch ein Vorteil sein.

Calculate LED current limiting resistor

To power an LED, the current that flows through it needs to be limited. For simple LEDs like the ones for signalling purposes, the cheapest and easiest way is to use a resistor in series with the LED, to limit the current. The question that normally remains is: Which value should the resistor have?