# Thread: Anyone interested in serial controlled Relay/Input card?

1. Originally Posted by DjBac
Phidget's kits are very good!!!
The voltmeters can handle up to 30V...
And the input/output card upt to 30V I think!!!

If I am wrong please correct me!!!!
Having looked at their kits :

http://www.phidgetsusa.com/tutorials...ifferences.asp

The Phidget 8/8/8 Interface Kit

8 Digital Inputs
Switch triggered - The digital inputs require only closing the inputs to the ground terminal via a switch, button, etc. No voltage should be used. The refresh rate is 125Hz for the Digital Input.

It says you only need to short the inputs to the ground. That clearly says all the inputs are pulled up to +5V. It need to be modified if you need to sense if a +5 or +12V is present such as the ignition.

8 Digital Outputs
The digital outputs put out +5V when turned on and 0V when off. The Digital Outputs have a refresh rate of approximately 125Hz.

This board will not drive car relays directly. You will need to add 8 relay driver thats capable of sourcing/sinking 150mA or so.

The analog inputs receive a voltage between 0 and +5V. The value is converted into a number in the code between 0 and 1000 respectively. The refresh rate on the Analog Input is 65 Hz.

As you said it can take up to 30V...thats probably true or not but the maximum it can measure before saturating is 5V. A voltage divided is needed to scale down the car battery voltage from +12V down to +5V or so.

The Phidget 0/16/16 Interface Kit

16 Digital Inputs
These inputs require that an external voltage source supply the power to input. A voltage of 4 to 30VDC will be read as a high or logical 1, below 3VDC will be read as a low or logical 0. The input is high impedance which means the current will be limited. The refresh rate is 125Hz for the Digital Input.

Sourcing a voltage up to +30V is fine for detecting +12V presence in a car. But what if you want to detect a closed door pins where the pins short the input to the ground? Alot of switches in the car tend to short its input to the ground. So again this need to be modified to cater for that.

16 Digital Outputs
These outputs require that an external voltage source supply the power. The outputs can sink up to 30VDC at 2A. This type of output is commonly referred to as "low side switching" The Digital Outputs have a refresh rate of approximately 125Hz.

This is fine as it can drive the relays directly. 2A sinking is over kill just to drive a relay though...all thats needed to drive a standard car relay is about 150-200mA.

The Phidget 0/0/4 Interface Kit

4 Digital Outputs
The 0/0/4 is a slightly different animal. This Interface Kit uses relays for it's outputs allowing it to switch up to 250VAC at 10A or 100VDC at 5A. This Interface Kit could be used in projects that need to turn on/off larger loads; incandescent lights, relays, solenoids, motors, etc.

Only support 4 fixed relays

Im sure I havent missed anything unless Im looking at the wrong page But the point is, none of the kit can work with the car without modifiying them or buying more than one items. As I said the only thing I liked about the kits is that they are all on USB port.

Only if microchip make flash USB PIC, Ill go USB all the way with my design. Unfortunately the USB PIC they have are only OTP. Windowed version of it for developements are not cheap.

But relax...I still dont have any update worth mentioning. Im still discussing some part of the design with another member in here and havent come to a 100% conclusion yet. And I have been away and been busy for the last few weeks. But as promised it will get done soon...very soon I hope

2. I suppose you are right!!
but for voltage measuring there is a sensor (-30V to +30V)...

So I will just have to wait!!!

3. Unless I missed something about the board you are making, since you are using serial as your communications method, you can only use as many boards as you have serial ports.. right? (Unless you plan on hving some sort of inter-board communication)

With Phidgets you can plug in as many devices as needed to complete the project. The 30V sensor is pretty plug and play (I have one.. havn't tested it yet though). And the relay baord uses good sealed relays suitable for automotive use.

I'm open to options, but what I have seen so far is pretty good for just being able to place and order, and have a working board in hand. I don't like the 5V stuff with Phidgets.. but so far its pretty easy to integrate with 12V

-Chris

4. Unless I missed something about the board you are making, since you are using serial as your communications method, you can only use as many boards as you have serial ports.. right?

Thats right. Although not cost effective but a USB-SERIAL converter can be used. This is the reason why I wanted to go USB but unfortunately its not possible for me to do it at this time.

(Unless you plan on hving some sort of inter-board communication)

Thats another idea I have been discussing with another member in here...maybe a plug in board. But then how many relays, inputs, ADC, DAC...etc does one really need? I hope 8 x relays, 8 x inputs and 4 x ADC is more than enough for most application. A DAC maybe useful? I cant think of any application though.

And the relay baord uses good sealed relays suitable for automotive use.

The relays maybe sealed but the board they are mounted on is not? I still like the idea of the relays being off board. It gives the flexibilty of placing the relays closer to the device that need controlling...running a long fat wire into the relayboard and back out again to control a high power device is not a good idea. Ill say keep that fat wire short while the relay control wire can go around the car

The 30V sensor is pretty plug and play (I have one.. havn't tested it yet though).

Please do let us know the results.

5. Phidgets kits (0/16/16) use for outputs switches to the ground!!! what does this mean?? Can this be used for A/C controlling? Maybe with a relay to each switch?

6. ## Parallel 8 relay board

Here's a site I found for 8 relays via parallel port. I have one of the boards and it works great, comes with software for windows too. No inputs though. Hopefully this site will be back up and working soon.

http://www.mobilecpu.net/showitem.asp?q=output&id=51

7. Bump

Any progress on this yet?

8. Bumpity Bump.

Any updates? Oh, and is this something we are going to be able to build ourselves? Or are we going to buy it from you?

Have you done any work on the software? Can you release the source?

The reason I ask is I am getting ready to install some switched devices, and was going to buy the 8 parallel relay board. If this board is getting close, I may just wait.

9. Im still working on it...it is nearly finished Was put on hold for a months or so due to work related stuff.

Circuit design 99%
PCB design 99%
Code 80%
Documentations 30%

There has been some slight change in the specifications :
8 x Relays
8 x Digital inputs

PCB is single sided 4x2 inches

Ill post the project documentation, source code, PCB artwork, SCH..etc.

So yes you can build it yourself.

All relays are placed offboard and can be added as needed since they are the most expensive item in the project.

Total cost to build is about 25USD excluding the add on relays.

10. This will also support a bootloader.

So any future firmware upgrade/modification can be done over the serial port.

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