Help me build a 1-wire interface to serial port

[mobile-it]

Hi all,

I want to build a 1-wire interface to serial port can someone help me out?

on the internet I found some schematics about 1wire to serial but they are all using the schottky diodes (I can't find those in my shop...)


thanks in advance

 

[VVV]

Re: 1-wire to serial

Can you post the links to those schematics? Maybe we can help if we understand the problem.

 

[IanP]

Re: 1-wire to serial

One option is the DS2480 1-wire-to-serial IC:
**broken link removed**

.. another option is the PICAXE microcontroller with it's 1-wire ready-to-go BASIC commands:
1-wire Serial No: "readowsn"
1-wire Clock: "readowclk"
etc. etc.

Regards,
IanP

 

[mobile-it]

Re: 1-wire to serial

**broken link removed**

This is the website with the schematic!

 

[mobile-it]

Re: 1-wire to serial

Here is the schematic:

 

[VVV]

Re: 1-wire to serial

Sorry, I do not see any easy solution to this. I do not like the approach, either. If I were to design something like this, I would probably use a CMOS gate with large series resistors on the inputs and connect that to the 18S20.

I think you will need the Schottky diodes if you are going to use the schematic as is, since they provide protection for the 18S20.

 

[mobile-it]

Re: 1-wire to serial

Ok, I will order them online because I have to order some other components too.

Thanks for your help

 

[melc]

Re: 1-wire to serial

Here is the schematic:

So, what's happening if by mistake one of the DS18B20 pins will make a contact with the earth ? (the PC GND is connected to the protective earth).
There is no limiting current resistor on the RS232 output, so all RS232 lines involved will use the self limiting feature of the internal TTL-RS232 converter, from the PC which is quite wrong...