tharding:
What process do you use to etch? (I use laser transfer/iron with muriatic acid and H2O2)
I do the same. I have been using kodak high gloss photo paper for the printing medium. I want to try clear overhead projector film when I attempt to do a double sided board.
tharding:
Does this connect directly to rs-232?
Not sure what this is? If you are talking about the RN-41 bluetooth ic.. It does put out rs-232 formatted signal at TTL levels. You would need to add a RS-232 driver to connect to a RS-232 port
tharding:
What are you using on the host computer to read the serial data?
I am using maxims java 1-wire api library to communicate via the bluetooth serial port on the host computer.
tharding:
Any fears of having AC and DC so close together in the same box (aside from being against electrical code)?
No fears. Just lots of caution when working with 110v AC. Each socket is limited to 5A. The ground and neutral wires go directly to the sockets and the power line is switched by using mechanical relays. Of course the power module would probably not get a UL rating, but I am not looking at manufacturing them for resale and anyone building one does so at their own risk. I am sure the box could be redesigned to actually meet UL code standards. Again I consider the power box to be like a power supply module that plugs into the wall.
tharding:
I do have one qualm with your setup: you are sending 5v through a phone line to the relays (>100mA a piece, correct?). I believe the only reason this works is because of the short length of the cable. If I had the 5V power supply on the other side of the room, it probably would drop the voltage too much, right?
First the bluetooth module is meant to sit near the power module and the temp sensors not sitting across the room as that would defeat the purpose of eliminating the wire from the host computer to the bluetooth module.
Now lets explore the electrical aspects.
Cat 3 telephone cable contains AWG 24 solid wire which has a DC resistance of 0.0302 ohms per foot. If we had a length of cable 50' long, we would calculate the distance * 2 for the ground return, giving us a 100' length of AWG24.. which calculates out to 3.02 ohms. Now the relays I am using are 5v relays which operate at 89 ma each for a total of 178 ma if both are operated at the same time. Which would give us a voltage drop of
(v = IR) or 0.538v. So now my supply voltage is sitting at 4.5 v. still plenty of voltage left to operate the sensors and bluetooth module. The 1-wire sensor will operate down to a voltage of around 3.0v and the bluetooth ic likes 3.3v and the relays will operate down to 3.5 volts. So we could still operate everything at a distance of 50' axway from the power source.
tharding:
I wouldn't be doing x-10, but I would have a spare laptop in the brew area and just wire everything up through that and then online. I have been going through an arduino for my 1-wire setup and reading the serial data in processing, but considering I can get the DS2480B as a free sample I might try it out.
The point of the x10 module was to be able to remotely wirelessly control a 110v device from a computer. I accomplished this by building the power module, but those who don't have the skills to do circuit boards and want to buy an off the self product can use x10. I have in the past and it works just fine for turning the pump on and off.
Do you know of any 110v switching device that can be controlled by a computer program?
tharding:
Awesome setup. You MUST keep adding more things. Ever consider the cheap RF modules?
http://www.sparkfun.com/products/9582
or hooking the output directly to a dd-wrt router with serial setup?
Thanks.. It is great posts like yours that make us think hard about our setups and if there is anything else we could do differently.
You know I haven't. Before the bluetooth idea, I connected the 1-wire network directly to the host computer and communicated with the sensors via the serial port, using maxim's serial port adapter. I wanted to get rid of the wire running across the room so I dreamed up the bluetooth/1-wire module to eliminate the connection to the host computer. The 1-wire adapter also did not supply 5v to the network. By using bluetooth and its virtual serial port mode SPP I did not have to make a single change to the controlling software.