Completed Ardunio Contoller: Few Problems, Help Needed

[perikaruppan]

or Can i use Opto-Isolators between the I2C and the Power Module? i.e., the 25 Wires that take the Data to the Power Module, go through the Opto-Isolators and from the Opto-Isolators to the ULN2003 to drive the relay.

 

[BeanAnimal]

Power Supply: What will be the Capacitor values that are required? Even if i have inductors what value is required? Do you have a schematic that i use?

Schematic:
Will get one done soon and post it now

PCB: Yes i have the PCB Layout, will post the pictures soon.

Floating Pins: Will Change all the floating pins to INPUTS. To minimize the Antenna problems. Shouldnt this be OUTPUT?

They can be either, but setting them as INPUT and setting internal pullups conserves power. Your glitching could be caused by the AVR running out of power, or because of noise.

Without seeing your schematic, it is hard to tell what needs to be done to the power supply section. What regulator are you using?

Here is the power section of one of my AVR projects:
Electros are 470uF and ceramics are 100pF, inductor is 10mH

 

[coketech]

Can i try this, use a 12V/4A Adapater, just 1, and power the Arduino though pin GND and VIN in the board? instead of using it through the Power Plug IN of the Arduino? and power the Relays with the SAME Adapter? Will this solve the problem?

The atmega chips run at 5V so plugging that plug-pack in directly to the Vin pin would be catastrophic.. If you gave nice clean 5v on the Vin pin would be ideal.

Optoisolators have saved my bacon many times in the past, so they get my vote! The noise coming back off your halides and pumps could be an aggravating factor

 

[perikaruppan]

Bean, I am not using any Circuitry for my Power Source. These are regular Adapaters that you get in any store. and at the output cable i connected the 100uF Capacitor. as you have done, maybe i should try 470uF and a 100pF. Will do that and see what happens to my system.

Coketech, What do you mean by "nice clean 5v"? i am planning to use the same 12V/4A Adapter on the Vin. As in the specs, the Vin has to be more than 7V and Less that 12V.

Any suggestions on the opto-isolators? most of them are for 1 input, are there any for 4 inputs? so that i can reduce the no of ICs used.

 

[BeanAnimal]

If you are using an unregulated lineary power supply (a transformer and a bridge) and there is no onboard voltage regulator.... then you are going to have all kinds of problems. It is not a matter of a simple smoothing or bypass cap, it is a matter of regulation. Voltage fluctuations can cause glitching. I have no idea what is on-board a typical arduino... maybe they have an oboard Vreg. Again, without full project schematic, showing all parts and values, helping is like throwing darts in the dark.

 

[perikaruppan]

This is the circuit in the Contoller Unit: for the I2C's, a small error in naming the 3rd IC. It is not for the Keyboard Control, it is for the Float Switches. Can get inputs from upto 5 Floats.

Power Supply Adapater: using these power supply adapaters. Havent opened them to see what the contain.

http://www.ravirajtech.com/smps_power_supply_adapters_india.htm

Will upload my Power Panel Schematic in a short time

 

[BeanAnimal]

What about the microcontriller board? Can you also give details for that? Is it an off the shelf arduino?

 

[BeanAnimal]

Also does the arduino have on-board I2C pullups? How long is the I2C buss, does it need additonal pullups maybe?

 

[perikaruppan]

Bean,
It is the regular off the shelf Duemilanove Arduino. http://www.sparkfun.com/commerce/product_info.php?products_id=666

It does have internal pull up resistors on board so dont need them when using the I2C. And also, the ICs for I2C are a maximum of 4" from the board. You can see that in the images above.

 

[der_wille_zur_macht]

Put external pullup resistors on and try it again. The internals are VERY weak and known to cause problems. Anything between 2k and 10k ohms will be fine.

I never put much thought into the pullup resistors until someone showed me an oscilloscope reading the clock line with just the internals. The "square" clock wave was practically a sine wave!

 

[perikaruppan]

so from Arduino SCL to the SCL on my board i put a 4.7K Resistor is this correct?

or should be between the SDAs? or should it be between both?

 

[BeanAnimal]

SCL and SDA get pulled up to +5v

 

[perikaruppan]

+5V - Resistor - SCL
+5V - Resistor SDA

Right?

 

[BeanAnimal]

Yup

 

[BeanAnimal]

The same 5V that is on the arduino board... not your external PSU

 

[perikaruppan]

Yes.
Actually, the external 5V is powering up my Arudino, and from the Arduino 5V pin i am supplying my I2C Board. So in the I2C Board, if i put a resistor between the 5V and SCL and 5v and SDA is it Ok? the board is about 3"-4" from the Arduino.

 

[der_wille_zur_macht]

Yes that should be fine.

 

[der_wille_zur_macht]

Also something I don't see in your schematic or the photos you posted - decoupling caps on the Vcc pin(s) of the IC(s) you're using - especially that port expander that's causing the problem. Might want to stick a .1uF ceramic cap next to that chip.

 

[perikaruppan]

Then i need to redo my PCB.. dont have space or routing where i can fix the decouplers on around the IC.

have put 4.7k pull ups on the SCL and SDA Lines.

have put 100uF and 0.1uF between the +5 and GND on the power supply.

Going to test it. If not will redo the PCB with all the Decouplers near the ICs and power Supply.

 

[der_wille_zur_macht]

Good luck!