This project is based on Maxim's application note: Using a UART to Implement a 1-Wire Bus Master
http://www.maximintegrated.com/app-notes/index.mvp/id/214
The original version mentioned in Maxim's application note is shown as below.
Also a simplified version is available:
Resistors can vary from 200ohm to 20kohm. Transistors can be BJTs or MOSFETs. The diode used in the simplified version should be fast and has a low forwarding voltage. 1N4148 is known to work.
A USB to UART converter is needed. There are many USB to UART converters that have a TTL UART interface. RS-232 UARTs should be avoided since its voltage is very high and can damage your device. If you have to use one of such, insert a MAX232 or equivalent chip between the RS-232 port and the circuits mentioned above properly.
Here are a few models that are tested. Many of these are prices under $5:
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SiLabs CP2102 USB to UART converters (shown below) are known to work.
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Prolific PL2303 USB to UART converters (shown below) are also known to work, but most boards have problematic power output pins. Try to power your 1-wire device separately or strange things will happen.
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FTDI FT232L USB to UART converters (shown below) are also known to work, but they are more expensive than the former two types.
Type "make" to get "lsow" and "digitemp_evil" compiled.
lsow is a tool that list devices on a onewire bus connected to a USB to UART converter. Simply type something like "lsow /dev/ttyUSB0" and it will show device IDs found on the bus.
digitemp_evil is a demonstration program that reads temperature values from DS18S20/DS18B20/DS1822 onewire digital temperature sensors. Type "digitemp_evil /dev/ttyUSB0" and read IDs and values. Sometimes after powering up DS18B20 will give something like 85°C, you will just need retry.
