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1-Wire related hardware from Springbok Electronics
Let me start by explaining that I have little or no connection with David Lissiuk or his Springbok Electronics at the time I write this, other than receiving samples to test and having been given links on his site.
Prices and availability.... PLEASE READ THIS...
The information given below may well be out of date. It is presented only to give you an idea of what was at least once available from the sites. Prices are given excluding shipping.
I have seen, and played (briefly) with the following modules
LP-THS Line powered "Temperature / Humidity / Solar"
As with all of Dave's boards, there's a DS2433 EEPROM (512 bytes) on the Aux side of the DS2409.
On the Main side, there's a DS18B20 for reading temperatures. There's also a DS2438. (The DS2438 has a temperature sensor inside it, too. However, the separate sensor is not in an SMT package, so it is sometimes more responsive to changing ambient air temperatures. It also avoids the problem of some self-heating that the DS2438 seems to show.)
The DS2438 is a splendid chip. In the LP-THS it's ADC is connected, nominally, to a humidity sensor. However, it is not hard to put different sensors on the board. You might have to fool with the passive components establishing the offsets. The 2438 can, as well as reading humidity from that sensor, can read light levels (or something else) from a suitable two pin transducer with resistance proportional to the parameter to be measured. This channel was conceived as a light level sensing channel. The choice of photo diode is not trivial, though, if you want to pay attention to spectra sensitivities.
The board comes with dual RJ-45 connectors for easy daisy chaining of modules. Dave has put a lot of work into trying to get people to coordinate their use of the extra wires in RJ-45s... and he has provided various jumpers which can be made or opened so that his devices will work the way you want them too. (If only all designers were so modest!)
With all 1-Wire devices connecting with RJ-45s or RJ-11s BE CAREFUL about what the board designer used the extra connections for.... not all "1-Wire" devices can be interconnected without doing damage unless you make special cables to handle different uses of those wires. THIS IS A GENERAL NOTE and not particular to Springbok modules.
The board requires a 12v supply in addition to the standard 1-Wire I/O line. You can supply it though the RJ-45, or to header pins on the board.
There's an LED to show that the board's power supply is healthy, and another one (different color!) to show the state of the CTRL output from the DS2409 coupler (hub) chip.
Last, not least, the board (and others in the range) has a TL7726D clamp in the 1-Wire signal. This helps protect the 1-wire signal, working to reduce over-shoot and under-shoot and slightly alters its waveshape. The clamp can be taken out of the circuit by opening a jumper. (The circuit also has BAT54 and low capacitance TVS protection.)
LP-IButton: Temperature and iButton reader
Almost everything I said above also applies to this module.
However: Instead of the DS2438, there is a clip (just mechanical) into which you can insert iButtons. These are just various 1-Wire chips housed in a metal can like a small battery. So: No ADC, no light level (or other resistive) sensing. Temperature chip still present, DS18B20. There are various iButtons. One has temperature logging capabilities even when not connected to anything ("Thermochron"... see Dallas site.) All have the usual 1-Wire unique serial number, so you could issue any iButton that is gong cheap on eBay to people, and they would use them as "keys" by inserting them into the LP-IButton. iButton present: System will do something (turn off burglar alarm?) iButton absent: System enters alternate state. If you had multiple people with multiple iButtons, the system could compile logs of whose iButton was in the reader when. Ah, the joys of computing: The possibilities are limited only by your imagination!
Actually, that application wouldn't be a terribly good idea, as the clip really isn't meant for such frequent insertions/ deletions... but you could easily use the board and connect a different clip! The board would do fine for developing such an application, though! If the iButton humidity sensor became available again, the board would hold it. Using the board with a Thermochron gives you backup for the temperature data. Hey! We give you the hardware!! It's up to you to imagine ways to use it!!
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