Wiring a LED to IOCards

[Guest Raafie75]

How do you wire a LED to the Outputs of IOCards? Do you connect the Anode of the LED to the common 5V supply on Pin 1 and the Cathode to the individual 38 Outputs ?Regards,

[Guest Raafie75]

With all the IOCard users out there, no one can answer this simple question ?Regards,Brad Heller

[Guest sri777]

Brad,yes that is correct.You should first be testing all your outputs (as well as inputs) on the master card that way by connecting test led lead to each cathode pin at a time and make sure they are all recognized by the software. For inputs testing, you need to short the respective cathode/anode pins. - srini

[Guest sri777]

Well, though IOCards is an excellent hardware/software, sometimes it could feel like a lonely place. Recent times i noticed users switching from other systems to iocards for various reasons. But still one major disadvantage remains - lack of broad user community helping each other. Make it a habit to post your questions on IOCards message board also. There, atleast the guys behind the project answer your question 9 out of 10 times.-srini

[Guest Raafie75]

Thanks Srini, Much appreciated.I had posted the same question on the IOCards forums but wasn't getting any answers. So I thought I might try here.One other thing, what value of resistor do you find works well with the outputs. I just bought 100 of a 470ohm value, the same resistance recommended when wiring zero's for the Displays.I believe the Spanish Cockpit Builders meeting was on this weekend and thats why I didn't get any replies.Thank you again, its taken a weight off my mind!Regards,Brad Heller.

[Guest Binkles]

Sorry, don't really want to hijack the thread - but what are the advantages of hard wiring the 0's?

[Guest sri777]

so that you won't take up one output on the master card from the available total outputs. All constant displays such as zero's can be hardwired to a single output.-srini

[Guest CaptnKebec]

Hi there,I connected the LEDs with 220 ohms and I used the common GND (pin 2) to all the LEDs. Works fine for me.

[kiek 1,213]

Hi guys,It depends very much on the type of Led, i.e. 3mm, 5mm, built in a push button or stand alone, and you're taste (how bright do you want it to shine..).I use resistors varying from 220 to 470 ohm.Just try it yourself, and don't forget that there is a big difference between your cockpit at daylight and at night (you have to make a choise there).Regards,Nicowww.nicokaan.nl

[Guest sri777]

> what are the advantages of hard wiring the 0's?sorry, one of those hasty replies earlier. Did not realize you are asking about 7 digit displays. The answer is the same, but in this case, the reason for hardwiring zero's (7 seg display) is not to use up the available digit display output on the "Displays card". Each Displays card has 16 outputs and the idea is - not to use one of it for displaying a constant number such as zero (which has only on/off state). So you hardwire the zero digit as a simple on/off output on the mastercard. -srini

[Guest Raafie75]

I'm getting conflicting stories?Do I use the Common GND or 5v ?Srini, you seen to be the only one that has used the Common 5v. Does this definately work for you? I took your advice and started wiring my MCP that way.Could someone definately confirm this?Regards,Brad Heller.

[kiek 1,213]

Brad,If you use the +5V, the Led (or the segment of a 7-segment display) will always be ON (lit).If you want that it'okay, but if you want to control your leds via software, and I guess that is what you want, then do this:The output signal of the Master Card (one of the 38 at one of the connectors) is approximately 4.5 - 5V (if ON). All leds can be connected to pin 2 in that Connector (GND).So you the current will flow from a output (+5v) via a resistor, via the Led (anode connected to the resistor, normally that's the longest pin of the Led), to pin2 of the Connector..You can also use Regards,Nicowww.nicokaan.nl

[Guest Raafie75]

Does it matter which side of the LED the resistor is on ?Brad.

[kiek 1,213]

Brad,No, you could also put the resistor between the kathode lead of the Led and the ground. The resistor has to be there (in series) in order to limit the current, but it does not matter where. But if you omit it, the Led will burn just very shortly ... oops :-( ... and you can throw it away; you might even damage the output at the Master Card, if you're unlucky.For a basic course on Electronic, see:http://www.talkingelectronics.com/html/Page01.htmlRegards,Nicowww.nicokaan.nl