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

Originally Posted by kiltjim

Is this board going to be capable of digital outputs? Other than driving relays?
Is this going to be possible? Like instead of hooking up one of the outputs to relay hook it up to a transistor? Is this going to be too much for the board?

Yes you can drive other circuit, just dont exceed the maximum limit of the relay driver. The relay drive is ULN2803A which can sink upto 500mA each...more than enough to drive a relay coil.

Im not sure if you can switch the output fast enough such that it apears dimmed. The maximum switching is about 200Hz...most likely more.

Originally Posted by kiltjim

I'm working on something that will send some commands using VB.NET. Some simple buttons and all they do is send a command. Once this card comes out though, I'm going to have to change all the commands, but all you really need is a nice little .DLL thats allows you to access the serial port, or a USB port, or whatever.

That be cool, Ill need a simple interface...something like a skinable program which have :

For the relays :
LEFT/RIGHT UP/DOWN electric window button
LOCK/UNLOCK door button
BOOT release button
Rear window heater button
...etc

For the digital inputs :
Reverse camera
Movie/VIS lockout
Bonnet open
...etc

For the Analog inputs :
Car voltmeter
PC Temperature
Rear bumper distance sensor
...etc

Originally Posted by lez

well I was wanting to make a phone controlled car alarm

I have software in testing (sms) stage at moment, looks ugly but works, I can unlock/lock doors etc with a text meassage, now want to build in blutooth so I can unlock car from a menu option on my phone.

Sounds cool...how about the security? or is it just only from your phone it will accept the commands?

Originally Posted by lummox

Vaguely remember reading in the thread that the max current for a relay was limited, is this the case? If so would controlling a 100amp relau with a reed relay be feasable?

The 500mA output should drive a relay with no problem. The relay Im using for test is 30/40A relays and drain about 150mA. I dont know about 100A relays though as I have never seen them.

As long as the relay coil current doesnt exceed 500mA then all is fine.

Originally Posted by Ricky327

For the relays :
LEFT/RIGHT UP/DOWN electric window button
LOCK/UNLOCK door button
BOOT release button
Rear window heater button
...etc

For this, what type of commands does the board use to turn on/off an output?

As for the inputs, what would a typical output from the boards look like? Maybe I can throw something together before you get everything finalized.

The program I am working on doesn't make allowances for skinning, but I'm sure I could learn. Maybe piggyback on the frodoskinner, see if I can get it to work for mine.

This turn relay 1 OFF :
$RELAY 1,0

This turn it ON:
$RELAY 1,1

Set ALL the relay to "10001110" pattern
$RELAY A,10001110

The card status format :
$STATUS : 10011101,10010110,3FF,100,23A

The first 8-bits is all the current relay pattern, the second is all the digital inputs pattern. And the last 3 set of 3HEX are the ADC values. 3FF is the maximum value which equal to 16V.

Originally Posted by Ricky327

This turn relay 1 OFF :
$RELAY 1,0

This turn it ON:
$RELAY 1,1

Easily done.

Originally Posted by Ricky327

Set ALL the relay to "10001110" pattern
$RELAY A,10001110

Would this mean Relay 1 is on, relay 2,3,4 are off, relay 5,6,7 are on, and relay 8 is off?

Originally Posted by Ricky327

The card status format :
$STATUS : 10011101,10010110,3FF,100,23A

The first 8-bits is all the current relay pattern, the second is all the digital inputs pattern. And the last 3 set of 3HEX are the ADC values. 3FF is the maximum value which equal to 16V.

I htink I could handle this, however, it is going to be a little difficult to make this dynamic. For instance, if the user wants to make input 1 = car voltage, etc. Maybe an option box....

Alright, give me a little while, I might be able to bump something out.

Cool, thanks for the reply!

Next question...

As I stated in my original post I wanna use two of the three analogue inputs to measure the voltage of the 2 batteries and adjust the state of the relay accordingly. Will this simply be a case of plugging a line from each of the batteries +ve terminal, or is a reference (ground) required too?

Am I correct in assuming that implementing the program i wanna run will be a soft- rather than hard-ware issue?

Are you gonna be selling pre-etched PCBs or will we have to do it ourselves?

And finally...

Any ETA for this?

Thanks a lot

Would this mean Relay 1 is on, relay 2,3,4 are off, relay 5,6,7 are on, and relay 8 is off?

Sorry I should have made it clearer.

The format is RELAY A,[76543210]
So $RELAY A,10001110

Would mean :
A = Control ALL relays
Relay 7 = ON
Relay 6,5,4 = OFF
Relay 3,2,1 = ON
Relay 0 = OFF

The "$" character get the controller attention that a command is about to be entered. Each command must then be followed by a CR/LF character to indicate a command had been entered.

The command wont change much on the final version. The $HELP, $INFO, $STATUS command are already done.

Im also adding :
$DEFAULTRELAY = Set the relay default setting. On powerup/reset this relay pattern are used to set the relays.

$BAUDRATE = Set the rate, at the moment its running at 115200.

Hey, I just read up on this thread (I'm slow ). This looks awesome!

About $25 for parts was mentioned, but I assume this doesn't include the PCB? What are your thoughts on the PCB? It seems like it'd make sense for us to get them made as a group, since per unit costs go down greatly with quanitity.

I can also code a c/c++ dll to talk to the board, but it sounds like god_of_cpu has that covered in spades.