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

[Marc F Hult <MFHult@xxxxxxxxxxxxxxxxxxxxx>]

On Tue, 18 Apr 2006 08:52:28 +1000, "Rod Speed" <rod.speed.aaa@xxxxxxxxx>
wrote in message  <4aikhmFtlf7tU1@xxxxxxxxxxxxxx>:

>Marc F Hult <MFHult@xxxxxxxxxxxxxxxxxxxxx> wrote:
>> On Mon, 17 Apr 2006 20:39:07 +0000 (UTC), Byron Hynes
>> <bph@xxxxxxxxxxxxx> wrote in message
>> <50cb70804083b8c8303b6f56560c@xxxxxxxxxxxxxxxxxxxxxx>:
>>
>>> I think you have two choices:
>>>  1. Purchase an engineered set of matching products, such as those
>>> in the links below; or
>>>  2. Build your own.
>>>
>>> In order to do #2, you will need to understand more about the 1-wire
>>> protocol and wiring options than you seem to do at present. Have you
>>> read all of the appnotes and forum posts at the Dallas/Maxim site?
>>>
>>> I have four temperature sensors (DS18s20) currently logging using
>>> this:
>> http://www.electronickits.com/kit/complete/meas/ck110.htm
>>>
>>>
>>>
>>>> The problem is that
>>>> http://www.hobby-boards.com/catalog/product_info.php?products_id=108
>>>> implys that you cant just add a swag of 1820s in parallel to
>>>> http://www.hobby-boards.com/catalog/product_info.php?products_id=1503
>
>> Here's a third, choice that solves the multiple string problem.
>> This assembled board is available for ~$55 via PayPal from Dr. Peter
>> Anderson
>
>> http://www.phanderson.com/iom135.html
>
>> I have one and can recommend.
>
>Trouble is that it isnt USB.
>
>> It is designed to read and control *eight* strings ("runs") of 1-wire
>> temperature,
>
>And it must be possible to do a USB/1-wire converter that operates the same
>way.
>
>> dual 32-bit counters and  quad-input 12-bit analog input devices.
>
>Dont need those. And it makes more sense in my
>situation to use 1-wire devices for that sort of stuff.
>
>> Nothing else comes close to the versatility and low cost
>
>Thats arguable given that a USB/1-wire converter that can
>drive a string of 1820s should cost about $30 fully assembled.
>
>> -- and for a good cause (helps Dr Anderson's students).
>> Dr Anderson also sells many other devices including a
>> USB -> RS-232 converter if you need it.
>> www.phanderson.com
>
>Yeah, I've used him in the past, just doesnt have what I need in this case.

Your quest seems to have evolved, post by post into

a) multiple 1-wire channels (= "runs" = "strings")
b) controlled/read via USB
c) "should cost" =< than $30
d) price including  software "drivers"
e) in a single pre-constructed device
   (i.e., not USB-->RS232 converter + RS232--> 1-wire).
f) you do/don't want 1-wire devices that aren't temperature sensors

Which gives (me) the impression that you'd rather pose the problem than
solve it.

Peter's excellent, affordable solution is an 8-channel USB-RS-232 + PIC->
1-wire.

Maxim also makes the DS2482 IC2-> 8 channel 1-wire IC, but one has to get
from the PC to the IC2 interface which requires at least one more chip to
meet your stated need.

There aren't any 1-chip, USB->1-wire with multiple channels at this time as
best I know. Since you added the requirement of $30 cost late in your
evolving explanation of needs, consider buying 8 of your (hypothetical?)
$30/channel, one channel USB->1-wire converters for a cost of $240. Peter's
actual (not hypothetical) solution of USB -->RS-232 + PIC --> 8 channels
1-wire might be more attractive to you in that context.

Eight DS2490 USB to 1-Wire Bridge Chip's might fit in your budget but you
wrote that you wanted something that was already constructed ( and so ditto
with the DS2482-800 Eight-Channel 1-Wire Master).

(Fer hoots re-read your posts and responses for:

1) the inconsistency(ies) between what you wrote in your original post and
your response above (2 points)

2) the pertinent fact(s) about PHAnderson's offerings that you
misunderstand/represent (2 points) and

3) the additional requirement(s) you added after the original post
requirements (2 points).

Seven points gets you a 'B' ;-)

Marc
Marc_F_Hult
www.ECOntrol.org