Relays Board




Relays Board

The Relay board is used to control multiple relays and visualize multiple inputs of a PIC processor.  The idea was for remote control of relays and notification via the Internet, but Skype already closed it for external programs and for Viber and Telegram it is very difficult to make chat programs, in our case I decided through a simple Desktop program and through Remote Desktop access that relays can be switched on and off and monitor inputs for sensors. This is often required when you live in one city and work in another and have 2-3 or more residences in which you have feed animals, water flowers, monitor alarms or temperatures, or just manage some simple peripherals and appliances like a water heater, the stove or the washing machine. Additionally, you can install an IP camera to see what's going on. Previously, it was possible to use Skype as a guide commands and messages but since Microsoft bought it impossible. Thank them for their poor service.

The project basically consists of a Pic processor connected to a Bluetooth module, HC05, which can be purchased for $ 4, making the connection wireless , so it won't burn your computer if you mess up something or something goes wrong with the board. This allows the board to be positioned up to 10 meters where it is convenient to route the cables to the devices. The Bluetooth connection is password protected and encrypted so you won't be hacked. The Bluetooth module is configured before inserting the board as he is given a security name and password. An alternative to connection is ComPort as the scheme slightly changes and drops the bluetooth module and in its place or USB-RS232 or MAX232 converter. The software remains the same. Transmission speed is low in view of the slow human response and little transmission data, just no need for high speed.

remote control

remote control

As you can see from the diagram and the pictures, the outputs can be switched on with your mouse and you can observe them, and the inputs can only be observed. The software is made in two variants - 16 inputs and 16 outputs and 6 inputs and 24 outputs. In one case, you can use more inputs and fewer outputs a in the other case, more outputs and fewer inputs. For higher capacities, relays must drive contactors that are designed for higher current for more powerful appliances. The software is as simple as possible and is written on MPLAB and Delphi XE7. I publish the whole project for those who want to change it and get new functionality. For others, they can simply download the EXE and HEX files and use them the way they are.  The board requires 12 volts and 2-3 amps to power the relays. It is good that the power supply is transformer-proof so that it is disconnected from the mains and safe for people.  When the connection is Bluetooth, a USB Bluetooth module is installed on the computer, such as is sold in every computer shop for 10 BGN.  The program port is set and the program is written to STARTUP REGISTRY to start with the startup of the computer as well as the Remote Desktop software.  This will always give you access to your appliances even if there are power surges.

The board processor is a PIC18F46K22 model that is cheap and affordable. The oscillator uses a CRMX0400 ceramic resonator with built-in capacitors to replace quartz.  It is easier and not vulnerable to vibration and erosion. Its accuracy is not great, but it is enough to keep the PCB safe in summer and winter in cold and warm.  It is a good idea to isolate the inputs with optocouplers, they are 5 volt digital. A processor such as Pickit3 or the like is used to program the processor who can program it.

Relays Board

Source Code