Thread: New Fusion Brain User. Digital Input Question...

Originally Posted by josh14w

Hello,
I am new to using the Fusion Brain so I have very limited knowledge about the system. I just like working with electronics and stumbled across the FB a while back and thought I'd give it a shot. I have been doing some experimentation with it for the past month or so (have gone through the wizard, etc.) so I know some of the basics. I have experimented somewhat with the few sensors that I currently have (thermosensor, ultrasonic distance sensor, photosensor, and IR distance sensor) and I seem to have a general understanding of how they work. I am now at the point where I would like to start implementing some of the functions the FB can accomplish with creating a "smart room" in my house. My ultimate goal is to set up the FB to carry out some basic functions in this particular room such as "lights turn on when the door opens" or "heater turns on when temperature falls below a certain point." Many of these ideas are centered around me using a Digital Input which has been a roadblock for the for a while now. I cannot figure out how to implement the Digital Input into the FB and get it to produce my desired result.

I guess maybe there is a way to accomplish some of my goals without using the digital input, if so please let me know. Otherwise, if anyone has ANY advise for me to get me pointed in the right direction in regard to the Digital Input I would greatly appreciate it.

Also, if anyone has anymore creative ideas or projects I could set up in my "smart room" using the FB...PLEASE PASS THEM ON TO ME as I am definitely no expert on the system and probably don't know many of the interesting things it is capable of.

I apologize for this thread being too lengthy, but I guess I just wanted to try make myself as clear as possible and with me not knowing much about the FB I probably got a little too wordy. Thank you very much for any help you're able to give me.

To use a digital input, you have to edit the xml file manually. This is because we have dropped digital inputs in favour of more analogue inputs. All analogue inputs can be used as digital inputs, but digital inputs can only be used as digital.

So easiest, would be connect your input to an analogue input. If you need to use the digital inputs, some things to remember, are that you need to pull the port low or high depending on what you design. Right now it floats. So if you just attach a button, it will float around and not act as expected. Another is that digital inputs do not work in the configurator. The configurator will ignore them and discard them, making the configurator non-useable in that situation.

In the xml, the configuration is identical to the other ports, but the type is "digital input" instead of "digital output".

Also as to your home automation, you may want to add more feedback into the system than just the door to determine if the lights are on or off. Consider lights are off, you are outside. You go in, lights go on. Now if you leave the lights go off, but lets say Person A comes in. If you are just using the door as a basis, how does the program know if you went out, or someone else came in. It looks the same. Same if more than 1 person goes in at the same time, and leave seperately. Or if you dont close the door when you leave. Open loop systems are not stable. You can use that ultrasonic sensor and forget about the door itself. Another option, is get one of those motion detectors for security systems. They work off of IR, and are much better at detecting motion (from living things) to turn things on and off. You would just have to hack one so that when the light goes off, tell the PC or something like that.

Good luck with your project!

Originally Posted by bratnetwork

Also maybe consider Photosensor so the lights won't come on if its already light enough in the room...

The only problem i can see with the ultrasonic sensor, 2k1Toaster, would be if you have a dog or cat running around the house, but that could be easily solved by wrapping the dog in stealth material

Of course, there are lots of things to consider, but all good ones require feedback to know what it did or will do was done or should be done. Operating blind makes bad practice.

I had a similar idea several years ago but let it die because it would have been very expensive at the time.

What I settled on at the time was to install a pair of light beam type sensors in each doorway at a height that wouldn't be triggered by pets.

The sensors would be mounted on either side of the door frame so as to provide a space of a few inches between them. Then, someone going into the room would break beam "a" then beam "b" and increase the occupacy count by one. When exiting the room, beam "b" would be broken before beam "a" and the counter would be decremented. Once the counter reached 0 the room was empty and the lights could be turned off.

Now you would probably want to have a delay on turning the lights off so they wouldn't be constantly going off and on when you say, go to the bathroom or the kids run in and out of the room.

I don't know whether the photosensors are sensitive enough for an application like this but they are certainly cheap enough to try.

Originally Posted by Dan2008

I had a similar idea several years ago but let it die because it would have been very expensive at the time.

What I settled on at the time was to install a pair of light beam type sensors in each doorway at a height that wouldn't be triggered by pets.

The sensors would be mounted on either side of the door frame so as to provide a space of a few inches between them. Then, someone going into the room would break beam "a" then beam "b" and increase the occupacy count by one. When exiting the room, beam "b" would be broken before beam "a" and the counter would be decremented. Once the counter reached 0 the room was empty and the lights could be turned off.

Now you would probably want to have a delay on turning the lights off so they wouldn't be constantly going off and on when you say, go to the bathroom or the kids run in and out of the room.

I don't know whether the photosensors are sensitive enough for an application like this but they are certainly cheap enough to try.

That is still an open loop system though and inherantly unstable. I am not saying it wont work, but it is better to do something based off a direct sensor reading. If you are reading "# of people" you need a sensor that can detect people.

As to the photosensors, if you put a shield around it, or put it recessed a bit, you can then shine a light beam well. Without shielding the sun may trigger it as well.

Oh, its FAR from a good design. The reason for the two beams was simply to override motion (or other) sensors if the occupants of the room were still long enough for the timer to turn the lights off.

All-in-all, its still a tough nut to crack. For every sensor type I can think of there is a reason that it would not work. Heat sensing--large pets, motion--pets/remaining motionless, etc.

What I was trying to achieve was having the lights turn on when the first person entered the room and remain on until the last person exited the room. When the last person exited the room, the lights would turn off immediately.

I would still like to put something like this together if you got any ideas. I've got a bunch of X10 stuff and it works okay. Turning lights on or off based on a schedule works just fine as does the motion and light detectors. The only problem is that the lights turn off after a set period of time when activated by motion (after the motion ceases) and I want to keep the lights on while I snnoze in front of the TV.