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

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

Huey <no@xxxxxxxx> wrote
> Rod Speed rod.speed.aaa@xxxxxxxxx wrote
>> No <no@xxxxxxxx> wrote:
>>> 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.

>>> Perhaps it is just that I'm tired,

>> Likely.

>>> but are you looking for an "I can solder" solution or
>>> an "I can't solder" solution? (I need more sleep.)

>> I would have thought that was clear
>> from 'What I want is a fully assembled'

>> While I can and do solder, I was hoping someone
>> had designed their USB/1-wire converter/adapter
>> to provide enough 1-wire power to be able to
>> handle a decent number of 1820s as supplied.

>> If I cant find that, it would be no big deal to have
>> a single extra bit between the converter/adapter
>> and the 1-wire bus that provides that extra power
>> and I am happy to solder that up.

> Is the "extra power" that you need an
> increase in voltage, current, or both?

Its more complicated than that with 1820s.

Pete Anderson appears to do nothing special, using the parasitic
power mode for the 1820s, but he doesnt say that too clearly.

The other possibility is to just have an extra wire in the
4 wire phone leads to the 1820s and provide say 5V
down that if there is a problem with just parasitic power.

> Or do you mean something else by "extra power",
> like extra connections? Or what?

See above.

> Are you saying that you need multiple independent 1-wire buses,

No, I was hoping to avoid that. And it appears from
Pete Anderson's approach that that should be fine.

> or multiple connections to a single bus?

Yes, like I said in my original.

>>> For the first: www.usbmicro.com

>> Cant see that that is a very viable approach. It makes more
>> sense to use a standard USB/1-wire converter/adapter