PC Project

Simple parallel port programming example

The parallel port normally used on interfacing with printer, external zip driver, external 
CD_RW, scanner. The parallel port can be programmed to interface with custom design electonics 
device. The hardware of this port cosists of 8 output data bits, 5 input control bits and 5 
output control bits. More detail description of the parallel port can be find at beyondlogic 
and how to program the parallel port for beginer can find here www.ctv.es
The following example shown how to programme the parallel port. Only 8 output data bits was 
programmed and the source code included. 






Simple parallel port circuit for display result 



  


The source code written in C++
download source code
 



The setting of delay timing of program will depend on CPU speed. You can use the timing delay on 
C++ library so you can set the standard timing at any computer but the minimun time delay can 
achieved was 1ms. It can be improved at less than milisecond by certain timing technic. You can 
learn more timing technic  with document :pctim003. 





Reference:

www.beyondlogic.org
 - a lot of good information about the parallel port, serial com port and other
PC peripheral interfacing.
www.programmersheaven.com
 - -pc interfecing and a lot of programming tutorial, source code and information




Peltier Cooler

This cooler had been tested and working well but not test on any CPU yet. The PWM controller 
and peltier element can buy from www.oatleyelectronics.comThe prices for peltier element between 
US12.5 to US15 for each unit (power from 60W to 80W). This pelteir cooler not only use for 
cooling the CPU, it is also can be use as portable battery-operated 
cold reservoir, laser diode cooler, liquid cooling and so on.


  



 More peltier cooler reference at: 







X-Y table project

Two 1.8 degree stepper motor used for this project. However the resolution can be increased 
to 0.9 degree or 400 step per resolution by half step driving method. The stepper motor driver 
using programmed pic16f84 or pic16f627/8 MCU as controller chip. Click here stepper controller
to shown the circuit diagram. For more detail of this circuit, go to the pic microcontroller page
pic project. A few photo of plotter shown as bellow 


[plotterc1]  [plotterc2]   [plotterc3]


The software used to test the X-Y motion (writte under Delphi 5) can download here: X-Y motion test. 
The mechanical design of center supporting shaft to obtaining smooth movement without needed 
of carefully aligment. Two end of one movement axis was supported by bearing. You can attach the 
small power CO2 laser to this X-Y table as laser cutting or marking system. You can also attach a 
pen to the X-Y table as simple plotter system. The software for the X-Y table act as plotter download
here:  X_Y_plotter. One of the plotting results as shown as following photo:



 


More reference on X-Y table project can find here:plotter site






Serial Port Project

RS232 chip normally used for point to point communication. For multi drop communication circuit, 
the RS422 or RS485 chip are widely used. However, it is possible using the RS232 chip for multi drop 
communication with the daisy-chain configuration as mentioned at this website: 
:www.maxim-ic.com/appnotes.cfm/appnote_number/723. 
The following diagram shown the multi drop communication configuration using the RS232 chip. 

 

You can connect more that two units of RS232 device (maximun not sure, I am only test up to 6 device). 
It also possible to configure as multi point (multi master) configuration by some modification of above circuit. 
Click following picture to veiw the multipoint circuit\

[plotterc1]


If you want more reference on serial comport interfacing (RS232, RS485) using delphi, visit this 
website:sourceforge.net/projects/comport/. The comport component create by the author is very good serial 
communication component under delphi.







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