Elektronik / Mikrodenetleyici Projeleri/

PIC18F2620 PC üzerinden RF ile Display Kontrolü

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Değişik bir uygulama işin içine bilgisayar girince daha çekiçi oluyor Tarih saat hava durumu rüzgar vb. bir çok bilgiyi bilgisayar ile seri protoköl iletişim kuruyor Kaynak C dili hazırlanmış kod kontrol programı pcb şema dosyaları var

A Scrolling Display with RF connection to a PC

For a long time, I wanted to make something out of a large array of lights but wasn’t sure how to connect up a large number of them when microcontrollers do not have enough output pins for each light. From the Internet, I learned that the same persistence of vision tricks that are used to make a CRT display work could also be applied to LEDs in a grid pattern. I started with a very simple display that displayed the time and date. Then I realized that I have an automated weather station and maybe I could send weather data to the display from via a RF link. I built two perfboard/punchboard versions before reaching this version which is made fully out of manufactured printed circuit boards.

The concept behind persistence of vision is that if a bright light is flashed the light will be perceived as being lit for a long time. If the light is flashed rapidly enough( 60Hz in this display ), it will be perceived as being constantly on. The display uses this trick to allow a small number of lights to be on at a time.

The lights are arranged in a grid pattern with all the lights in a column sharing a positive terminal and all the lights in a row sharing a negative terminal. All that is required to light a light is to turn on the column and row for that light. The downside is that either only one row of one column may be on at a time, but looping through the grid from left to right and top to bottom with only a small number of lights needing to be on at a time and using a small number of data pins.

A mini-itx PC running Windows XP retrieves the weather conditions from my Lacross weather station via a serial interface, processes and records the data, then sends it to the three displays I have in my house via a USB connected RF module. The RF module hardware is identical to my PINGPONG-CDC unit except the module has a different firmware. BTW, the mini-itx computer also runs this web site.
HARDWARE

Building large complex boards is very risky. If anything is wrong with the board, the entire board needs to be discarded sometimes after expensive components have been soldered onto them. Instead of have one big board, the display is split into module boards. These modules are the LEDPANEL( front panel with the lights and buttons ), LEDDRIVER( hardware to switch on and off the rows and columns ), and the PROCESSORBOARD( the board that contains the RF circuitry and microcontroller ). If something goes wrong with one of the boards, only that board needs to be redesigned or replaced. A secondary bonus is that the processor board can be redesigned for a different PC connection. An example would be a module with a USB connection to a PC rather then an RF link for cost savings.

The main source code file of the firmware is main.c. As usual, the firmware uses all three priority levels available to the processor. The high priority interrupt is responsible for incrementing the millisecond clock, scanning the keypad for key state changes, and handling new bytes on the RF connection. The low priority interrupt is responsible for scanning the display data bitmap and loading the MCP23S17s depending on the byte that is to be displayed. The main body of the code is responsible for scrolling data and building the bitmaps which are loaded by the low priority interrupt. Double buffering is used to ensure the display state doesn’t change in the middle of a LED scan. As one bitmap is being displayed, another bitmap is being created.

The RF data is a simple fixed length packet. The start of a packet is 4 magic values, followed by the display data, and then ends with checksum. If the magic doesn’t match or the checksum is incorrect, the data is discarded. The RF connection is a simple unidirectional connection that uses a static channel which is configurable from the display unit. The transmitter is not constantly on. It powers off when not updating the display.

The display has 5 different modes of display which are selected randomly. Each mode has a different function in the firmware that is named the same as the mode. These are Static Clock( a static display which displaced the current time ), StaticWeather ( a static display of the outdoor temperature and humidity ), ScrollingClock ( scrolling display of date and time along with the sunrise and sunset time for the day ), ScrollingWeather ( scrolling display of outdoor climate temperature, temperature extremes, humidity, pressure, and rain ), and ScrollingIndoorWeather ( indoor temperature, indoor extreme temperatures, and humidity ).

Kaynak: http://www.raccoonrezcats.com/rfdisplay.html alternatif link : PIC18F2620 PC üzerinden RF ile Display Kontrolü

Dosya indirme LINK listesi (TXT formatında) link-3313.zip şifre-pass: 320volt.com

  • riza

    proje dosyaları gözükmüyor ama site ismi werebilirmisiniz??

  • arda

    merhaba rxm-900-hp3 rf modulu nerden temin edebilirim. yardımcı olabilirseniz çok sevinirim ardanejat@gamil.com