relays, and GPO Questions

[miniminus]

elloooo matrix orbital peeps !

first must say, what lovely devices ya making really makes custom PC the best ! everthing all there in one neet package !

ok to my questions have 2 main Qs .. ..
1, is there any way to increase the amount of GPO's namly on a VK204-24-USB, are there any more outputs left on the pic16f877a ?? as im not afiad to start modding it up

or anyway of modding the exsiting ones to get more ? like some kind of module to interface/inteprete though some kind of sequence !? clucthing at staws here !
but mainly anyway of increaseing the amout of low level GPO's etc

2,at present am using 2 of the GPO's to control relays which in turn control, 1 a CCL, and 2, video switching
BUT sometime it has issues, switch on GPO, relay switches on fine, switch off GPO and the relay will either take a while to switch, or the relay will hang half on .. and not 'click' right out ...
is there a reason for this ! ? as it always seem to switch on OK but to switch off it dont !
tried dif resistor values and even got it to work the other way round !

also can u use the GPO's to drive small 12v relays ???


anyhelp would be great Mick ...

[Raquel]

Hello Miniminus,

Thanks for your post.

Is it possible for you to send me some kind of schematic for your connection of the GPO and the relay?

GPOs turn on and off in an instant, because they are output ports of a uC, but its the resistor/cap network you have that characterizes the action of the relay.

Thanks,

[miniminus]

just have a siimple resister in line i found 200ohm worked the best (the relay has a resistance of 50ohms i thinks...
as it work's ok on the CCL relay
but not on the relay thats switching video fees ...
but on that relay im using both contacts not just one side if ya follow ...
or ...if poss, whats the circut diagram for the main high power GPO as i could just use that circuit as it seems that it works if i use one of those outputs (as in circut after the main pic, as all th eactual feeds come from that, just the low level gpos, come direct from that via a smal resistor etc)


what about my other Q ?
mainly can it drive 12v devises as long as they are only drive small devices (low amp)
and how about increasing the number of GPOs...
or if theres not any more outoputs, how about have the exsisting GPO have 2 states .. NC, 0v and 5v (something i thought of today!)

cheers Mick ...

[miniminus]

well no reply as yet

well to anwer my own question and to get some more opinions ..

first thought was to use transister that way that will be more of a definate on or off... a simple transistor circut will be easy to fix up... so which ansers that Q.
then i got to thinking, how about using logic gate
got to thinking of logic gates because, on initial thinking of swutch transistor with a earth u would always get the opposte effect ... (GPO on the transister would be of and vice versa)

but yes on logic gates, i could use two GPO in cunjuction though a logic gate and with those GPO being one of them on, or both on or both off .. i then have three different stats with only 2 GPOS... (im sure theres more ways of thinking but ya gets my line of thought here !)

so to some up ive answrd my own Q, hopefully i can put them into practice
any thoughts of other people ???

Mick ...

[miniminus]

ok as no 1 seems interested, will carry on talking to me self
may inspire some1 ? !

transistor worked flawlessly top job ... easy stuff

had a play with logic gates etc .... but with a little more thought you could not use logic gates with this set up, as setting up the inputs would be a nightmare (in software) so not worth anymore thought ...

BUT while messing with the transistors got me into thinking (again) ...
there would be a way to have two steps in each GPO ...
like 0 1 2 (thats when 2 was active so would 1)
you would use the flash function of he GPO's
put that though a capacitor to smooth it out then u would have that active which once smooth would give a small voltage out say 2v which would drive transistor 1.... but not enough voltage to drive transistor 2.....
then on gpo on full would of course drive transistor 1 still, and also boost voltage to then switch transistor 2
you may even with carefull resistor/capaciter selection, have 0 1 2 3.
off, flash, strobe, on ... but i think the distinction bewen flash and strobe would be hard to define definitivly ....

will make up the circut later today and tell ya how i gets on !!!

but whats ya thinks people ?? Mick ....

[Raquel]

Hello Mick,

Sounds like you have some neat ideas there. Please keep us posted.
As per your questions:
"also can u use the GPO's to drive small 12v relays ??? "
yes, you can. I thought you are already doing that.

"and how about increasing the number of GPOs... "
unfortuantely, there are no more extra pins that we can use for GPOs, this also entices a change in the PCB which is a major thing to do

"or if theres not any more outoputs, how about have the exsisting GPO have 2 states .. NC, 0v and 5v (something i thought of today!)"
again, this is not possible with the same I/O pins.

[miniminus]

well have been playing and i can see how you CAN set it up, not had the time to properly get the circut working correctly .. but did kinda have it set up ..

the first setting were u use the flashing mode to switch on ya 1st state is the easyiest ... using a capacity to the base of a transistor to smooth it out ..
altering the value of the resistor/capacitor i reckon u could get the dif between the strobe and flash ..

the hard part is putting in a delay to stop the flashing signal effect the 2nd state, as it has to delay switch on (bit like inverse of the 1st state relay) the use of zenor diodes and stuff would be used there ...

but i think with some thought and time to play it can be done !
i mainly wanted it for diff states of lights on ...
would be off,
1st state (LED flashing) would be say small lights on in case like bright leds etc
2nd state would be nice bright CCL, (and of course the 1st state would still be on)

with some gate action u could turn the first state off even !!)
may put some time into it later but my project been goin on long enough and just want me PC back together ! lol will post some pics of what im controlling and all me PC mods maybe ?


Also while im postig have a issue with me displays GPO's !!!
they all work fine can switch um all ok, can change the fan speeds and the speeds are read correctly ..
but like say every 10mins or so all the GPO's will like reset...
all GPO, and fans will alter (fans speed up speed up normally) only lasts a split of a second
then goes back to the default turn on state ... !! ??
the screen is completely uneffected when this happerns


Mick ....