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Topic: Room Management System (Read 2073 times) previous topic - next topic

8666

This is small Building Management System...just for my bedroom/workroom

Inputs are motion detection, temperature, light level, 2+2 buttons (2 can not be locked, just press and release).

Outputs are speaker, 4 power sockets at 220V, logging to SD card, sending commands to the PC.


I used Arduino Uno + Memory Shield from Snootlab


I have finished the basic software (turning backlight when going from bed to bathroom in the middle of the night) but I want to do full alarm system (with pass key to arm/disarm), maybe triggering webcam to take a shot and play load music from the PC.

I hacked a Gembird Powershield (PC controlled 4 socket switch) that has buggy firmware so it is useless after some time...now it is Arduino controlled.

Things to fix (ideas?):

- Turning two fluorescent lamps on one socket makes a problem on turn off. It is huge inductive load and breaks the communication to PC (need to reconnect the USB) ...seems like the Arduino continues to work. I do not know exactly how lamps can influence my system. (on the manual from Gembird it is noticed to not put inductive loads on the socket)

- Resistor Ladder for the buttons are with huge resistance and there is a noise (small current on measuring resistor). Seems like running the Arduino connected to powered USB HUB fix this problem a lot. Will some capacitor on 7805 output fix this? I have a big one 47uF but it does not have any effect.

Photo


Schematic (Is there any better software for this? Portable + Windows? Fritzing has buggy GUI)


8666

Thanks for the input KE7GKP

From the manual I read that 7805 should have 0.01uF on the output side. I do not have many caps in my collection so that's what I put for test. I have one HUGE 0.47F! 5.5V Will this help on the input side?  The input side is over 5.5V. With this one I can probably run the board for bunch of seconds if no relay is activated

8666

#2
Aug 08, 2011, 12:24 am Last Edit: Aug 08, 2011, 08:32 pm by 8666 Reason: 1
I was very bothered with the problem I had when switching off fluoroscent lamps with my System. I did redesign on power lines: Now have caps on the 7805, on the ULN2803 that is bit away and is completely galvanic isolated from the Arduino as now I power it from the 12V (have a supercap as a backup power) supply. The 6V mobile charger is now for relays only (Grounds/Minuses are not connected with Arduino). The problem still exist.

After tests... the conclusion is that the inductivity from the lamps generate a huge spike on switching off that affects my system from the other way around. It is not filtered by PC PSU and makes a problem on the USB line (hard to believe). The problem is removed if I connect the PC to another 220V wall socket that is on other phase. If both the PC and the lamps are inside (on the same side) from the protection of the powershield that I control it blocks the PC-Arduino serial communication. Powershiels has 2 sockets that are always one + 4 controllable. Probably will buy better power supply/ignition system for the lamps.

On the other side, I have very little noise now on the AD lines as the 6V was not good enough to power both relays and the Arduino and the sensors. Supercap takes a lot of time to fill as I put larger 180 Ohms resistor (not 100 as specified)

Updated drawing:




EDIT: Seems like puting SUpercap on the output of the 7805 is bad idea. I was thinking that on power loss current will not flow back to 7805 but it looks like from the internal design Vout is connected with resistor to ground + there is a note that it can damage the regulator if Vout > Vin... hmm My supercap is limited to 5.5V and will be problem to put it on the input side...putting diodes on the output side will lower the voltage too much.

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