Raspberry Pi

Change Raspberry Pi I2C Bus Speed

Changing the default I2C bus speed on the Raspberry Pi can help improve the performance of some projects. This is particularly important when using the I2C interface to control a display module. In the newer versions of Raspbian this change must be made using a Device Tree parameter.

The bus speed is sometimes referred to as “baudrate” although the two aren’t actually the same thing.

RC522 RFID Tag Reading with the Raspberry Pi

RC522 RFID modules are a simple add-on you can connect to a Raspberry Pi to read MIFARE tags and cards. This is potentially a great feature to include in a security system or any application where you need to identify an object or person without them pressing buttons, operating switches or other sensors. The contactless tags can be carried on a key-ring and the cards fit nicely in a wallet. Both of them can be hidden inside other objects to give them a unique ID that can be read by the Pi.

Enable 1-Wire Interface on the Raspberry Pi

The Raspberry Pi has a 1-wire bus which can be enabled on GPIO4. It provides low-speed data, signaling, and power over a single conductor.  This is commonly used on the Pi to connect low-cost sensors devices such as the DS18B20 temperature sensor.

Step 1 – Enable 1-wire Interface

The default Raspbian image disables the interface by default so before you can use it we must make a configuration change. This can be done using either of three methods. I’ll describe all methods but the first one is probably easier and quicker.

Using an I2C OLED Display Module with the Raspberry Pi

Miniature OLED display modules are a great way to add a small screen to your Raspberry Pi projects. They are available in various sizes but common sizes include 128×32 and 128×64 pixels. The cheaper ones have single colour pixels that are either white, yellow or blue. My device has white pixels and uses an I2C interface which only requires four wires to be connected to the Pi.

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