[SOLVED] how to run multi rx tx in microcontroller

[sunmeetrihan]

how can i add gsm modem, bluetooth module with pic microcontroller

actully i ,m making a project with my pc where i control a microcontroller through max232 with my voice.i also want to add a sim300 module and a bluetooth module to run operate relays so there for these module use rx tx of microcontroller but pic16f877a has only one rx tx..how can i use multiple rx tx from it..

and 1 thing more do anybudy knows how to get voice response from pic via computer bcoz dont want to use apr9600. it can operate only 8 voices..

ex.. if i say turn off light then it answer me back..(whatever i program)

PC---> MX232---> PIC16F877---->RELAY
| | |
| | \
VOICE RESPONSE <---| \
| TO BLUETOOTH MODULE & SIM 300-----> RELAY
|
TO PC

AND WHAT EVER I WANT TO AD LIKE PIR SENSOR, SMOKE SENSOR

 

[Tahmid]

You can use software UART. Your compiler may have library routines/functions for that.

eg mikroC:
https://www.mikroe.com/download/eng...mikroc/pro/pic/help/software_uart_library.htm

 

[sarathsnairpoonjar]

i think connecting tx and rx to a relay will solve your problem

 

[Tahmid]

You might be able to use a chip containing "switches", such as the CD4066. www.fairchildsemi.com/ds/CD/CD4066BC.pdf

 

[sarathsnairpoonjar]

is it costly comparing to a relay?

 

[Tahmid]

According to the prices listed here, it seems quite cheap: https://www.mouser.com/Search/Refine.aspx?Keyword=cd4066

For only signal switching, it will probably be cheaper than 4 relays.

 

[sarathsnairpoonjar]

how we are going to connect tx and rx to this chip?

 

[Tahmid]

If we use 2 of these chips and connect the RX of the microcontroller to all the inputs of 1 chip and the TX to all the inputs to the other, we can connect the RX and TX (by controlling the switching using the microcontroller) to 4 separate devices. So, we can use one UART module for 4 different purposes/devices. The only downside is the additional pins required to control where the switch will go.

Other such chips you may look at are the CD4016 and 74LVC4066.

Hope this helps.
Tahmid.

 

[sarathsnairpoonjar]

If we use 2 of these chips and connect the RX of the microcontroller to all the inputs of 1 chip and the TX to all the inputs to the other, we can connect the RX and TX (by controlling the switching using the microcontroller) to 4 separate devices. So, we can use one UART module for 4 different purposes/devices. The only downside is the additional pins required to control where the switch will go.

Other such chips you may look at are the CD4016 and 74LVC4066.

Hope this helps.
Tahmid.

yeah that was the point i am thinking about.......... saving pins....to control a relay single pin is enough, thats the benefit....

 

[Tahmid]

yeah that was the point i am thinking about.......... saving pins....to control a relay single pin is enough, thats the benefit....

Controlling a relay requires one pin. Controlling one switch on the CD4066 or similar device also requires one pin. The TX, RX connections would be required for the relay and the CD4066. So, controlling a relay requires same number of pins as controlling CD4066. Plus, one CD4066 has 4 switches. So, you may reduce current draw, save space and also save money when using the CD4066.

 

[sunmeetrihan]

can all things like gsm module or mx232 or bluetooth module work on same time..with relay or cd4066..like equal work.
and also thx both of u..
and what are the control a b c d for..in diagram

 

[Tahmid]

can all things like gsm module or mx232 or bluetooth module work on same time..with relay or cd4066..like equal work.

Not at the same time. Not simultaneously. But one after the other. Example: Send data to or get data from GSM modem. Then use the bluetooth module. Then communicate with PC.

But then again, PIC 16F877A can't do two processing tasks at once. It'll do one first and then the next one. So, you don't need to use 3 UART devices simultaneously. You'll end up using them one after the other.

and what are the control a b c d for..in diagram

4066 has 4 switches - A, B, C and D. Control A controls switch A. Control B controls switch B. Control C controls switch C. Control D controls switch D.

Hope this helps.
Tahmid.