16 Channel RS485 Modbus Relay Board

Controlling a 16 channel RS485 Modbus relay board is discussed in this post. The board needs to be powered with a 12V power supply. It has has a DIP switch to set its ID. If only the switch 1 is on and others are off, its ID will be 1. To communicate the board from a PC, a USB to RS485 converter can be used. The setup is illustrated in the following figure.

Figure 1. RS485 relay board using 12 V power supply, and a USB converter.

Alternatively, you can use a USB UART adapter together with a UART to RS485 converter. Wire connection for this setup is shown below.

Figure 2. Wire connection for UART to RS485 converter.

Unlike conventional RS485 devices, these devices do not have the control line for transmit or receive. They use autoflow control as shown below.

Figure 3. RS485 autoflow control.

V4L2 Capturing as Bitmap Image

V4L2 (Video for Linux 2) consists of drivers and API for video capturing on Linux [1]. In this article, we will discuss about using the library and analysis of video capture example. There are utilities for controlling media devices on Linux called v4l-utils [2]. We will explore about using and testing webcam with them also.

• Setup
• Capture Example
• Analysis
• Capturing BMP Image

K82 USB CDC Virtual Comm

In this article, we will discuss about using K82 as a USB CDC virtual com device. Setting up environment for K82 development is discussed in previous article at the following link.

http://cool-emerald.blogspot.com/2020/01/getting-started-with-frdm-k82f.html

• SDK VCom Example
• Ring Buffered VCom

Software timers and Ring Buffered UART Com for Kinetis K82 MCU

In this article, I would like discuss about using Kinetis K82 MCU with MCUXpresso IDE. I will use FRDM-K82F development board as a hardware platform. Setting up environment for K82 development is discussed in previous article at the following link.

http://cool-emerald.blogspot.com/2020/01/getting-started-with-frdm-k82f.html

• SDK Example
• Soft Timers
• Com

DrawBot XY Plotter with Arduino GRBL Controller

In this article, I would like to discuss about using DIY XY plotters which are also called draw bots. You can buy them at online stores such as LYCNC store or Global Tech. Factory Store on Aliexpress.

• Overview
• Controller
• Calibration
• Drawing