Need checking on project connection

[windpath]

Basically my project is about weighing system of recycled material. Therefore this is my circuit. Is it necessary for me to use 8mHz Quartz to OSC1 and OSC2? It is also necessary for me to use RESET switch on the MCLR?? BTW where can I ask for guide in programming of the PIC16f877a using C complier, for 2 weeks I have been try to understand program the PIC16F877a but to no avail, I can't find suitable example and result.

 

[ericgibbs]

hi,
The 16F877A requires a crystal, a 8MHz would be ok.

A Reset switch is not essential, but can be useful when debugging your project.,

The 741 OPA's are not suitable for a weigh bridge, their specification is awful.

We need more details of the type of load cell, is it a Bridge type.??

A single 5V regulator would be enough to drive all the project, you dont need two.

The 4k7 on the push switches need to be connected to +5V pull up.

E.

 

[windpath]

bridge type load cell. . .
yes the 4k7 is connected to +5v. . . but i dun understand +5 pull up?? Can show me how or links?

 

[windpath]

initially I want to use the AD7195 for my project. But the component is not available in my country so I switch to OP AMP the basic way. . .