Re: 1-wire to USB converter that can use 1820s directly

["Rod Speed" <rod.speed.aaa@xxxxxxxxx>]

Dave Houston <nobody@xxxxxxxxxxxx> wrote

> The Elektor schematic I found shows it to be self-powered.
> Is that correct?

Powered from the USB, yes.

> It appears to use the same Maxim drivers linked
> in the DS9490R datasheet. Is this an HID driver?

Not clear to me what a HID driver is. It definitely uses java.

> If so, maybe Jan Axelson's page on VB & HID drivers will help.

>     http://www.lvr.com/hidpage.htm

Thanks for that.

> Why don't you like serial for this?

Basically because I dont have enough serial ports available,
the only one available is used for the X10 controller,
and USB/serial converters are too much of a kludge.

> I see no advantage to USB given that it takes
> 3/4 second to get a reading from a 1-wire device.

Sure, its not a speed thing.

> Is the 18B20 faster than other 1-wire devices?

Dont think so.

> It seems to me that off-loading this from the PC to a serial PIC that
> can report readings from multiple sensors is the best way to go.

Dunno, I basically have a number of temps that dont need to
be polled that often, every few minutes is fine, and want to
use those to control the X10 stuff, particularly with temp
control etc controlling a portable fan heater that I sit in front
of and other stuff like the heater for the beer brewing.

And other temp sensors that only need to be polled hourly at
most for more basic alarm stuff like the freezer has failed etc.

And some basic logging of temps in the house, hourly would be fine.

Serial is just a bit dinosaury if I can just have the string
of 1820s on a USB/1-wire converter/adapter with at
most say providing 5V to the 1820s on one of the
spare wires instead of parasitic power for the 1820s.

Nice clean simple design.



> "Rod Speed" <rod.speed.aaa@xxxxxxxxx> wrote:
>
>> Dave Houston <nobody@xxxxxxxxxxxx> wrote
>>
>>> I don't use 1-wire myself so am not familiar with its details but
>>> the DS9490R appears to do at least part of what you ask.
>>
>> Yeah, thats basically what the commercially
>> available USB/1-wire converters/adapters use.
>>
>>> The datasheet indicates there are Windows drivers for it.
>>
>> Yeah, tho I didnt find they are that convenient to use.
>>
>> I actually have the Elektor USB/1-wire converter/adapter
>> and have implemented it, with some downsides drivers wise.
>> Should try the latest tho, its been a while since I did that.
>>
>>> http://www.maxim-ic.com/products/ibutton/products/1wire_adapters.cfm#USB
>>>     http://pdfserv.maxim-ic.com/en/ds/DS9490-DS9490R.pdf
>>
>>
>>> "Rod Speed" <rod.speed.aaa@xxxxxxxxx> wrote:
>>>
>>>> I want to have a number of 1-wire 1820 sensors thruout the house,
>>>> and want to minimise the cost of those so I can use them wherever
>>>> it makes sense to have one like in all the fridges and freezers etc
>>>> so I can do basic stuff like alarm on out of acceptable range etc.
>>>>
>>>> The obvious way to do those physically is to use phone extension
>>>> leads with RJ11 connectors on each end. Just cut them in half
>>>> and solder a 1820 on the bare end of each half. Then just connect
>>>> them all in parallel using standard RJ11 sockets on vero etc or
>>>> in punch down blocks etc.
>>>>
>>>> What I want is a fully assembled USB/1-wire converter
>>>> that can be used to interface those to the PC.
>>>>
>>>> I also need at least a decent driver that can
>>>> be used from VBA from Access or Excel etc.
>>>>
>>>> The stuff thats obvious on the web mostly dont use such
>>>> unpackaged sensors. Cant see any reason why its not possible tho.
>>>>
>>>> It would be desirable to be able to use any standard
>>>> 1-wire sensor ics too, but not absolutely essential.