PIC relays control

[Pic_User]

For the kind of current your looking at. I would use a n-channel FET. I dont really have any easy way of making a schematic for you but I will try and explain.

Take the HIGH from the pic and run it through a series resistor that will limit the current to about half the Imax of the PIC (about a 100 ohm should give you about 12mA off the top of my head) hook the resistor to the gate of the FET put the load (your camera) in the source circuit and ground the drain.
Hope I have helped....

Bill12780

<img src="http://www.picbasic.co.uk/forum/attachment.php?attachmentid=1886&stc=1&d=118564652 0" />
5 V/100 Ohms = 50 mA
5 V/400 Ohms = 12.5 mA (half the Imax of the PIC)

[bill12780]

<img src="http://www.picbasic.co.uk/forum/attachment.php?attachmentid=1886&stc=1&d=118564652 0" />
5 V/100 Ohms = 50 mA
5 V/400 Ohms = 12.5 mA (half the Imax of the PIC)

oops....Sorry....it was late when I posted that. I think I was going for the four(4) key on the keypad and fat fingered it to the one(1) right below it.
(I mean 5/.0125 is easy math I do in my head all the time...had to be a typo...cant belive I was that tired! hahaha!)

Pic_user...You obviously have WAY more experience with this.

I will yield to your expertise here and bow out. I just thought that I could return the favor for all the help that I get here.

Thanks for correcting that.

Bill12780

[Pic_User]

Hey Bill,

I do exactly the same thing with resistors. I think in current, and sometimes go down in resistance value, to lower the current, oops. I also say “bigger resistor” when I mean a bigger current, oops. We all do that type of mis-speak, don’t worry about that.

You are more than welcome, to discuss alternate ways to do things. There is usually more that one way to solve electronics problems. Just as there is more than one way to program an algorithm. The fun of the forum is the multiple solutions discussed. Let the user decide which way they want to go. Or let their electronic junk-box decide for them. Please, always put your ideas into any thread that you want to help with. Your electronics experience is of great value.

I posted that CMOS schematic from your description. You had said you didn’t really have any easy way of making a schematic. If you look for a drawing program called “paint.NET” it is free and way ahead of MSPaint.

We are all in this together,
-Adam-

[bill12780]

Thanks Adam,

I appreciate your kind words of encouragement.

I just kinda felt like a dumb A** if you know what I mean. I feel like a leach around here most of the time because I am still very new to the PBP and the digital world in general. always asking question that I am sure to some are so elemetry they are bored to tears! I have not had to use it this sort of thing much in my career. Hence...Ignorance...

I will spout-off when I think I can help. But PLEASE if I am wrong just swat me on the nose with a rolled up newspaper!

Maybe one day I can actually be of some help! hahahaha

Thanks for the tip on the proggie...I will check it out. If I was at my work I would have just slapped something together in Eagle really fast. But I have never download it here at home.

Thanks again! (I need to program an F-key for that line)

Bill12780

[flipper_md]

thanks Gentlemen

all of this end up being very constructive for me, and now I just need to set my mind on what parts I will order to get things started!
My programmer is dead anyways, I've got plenty of time till the new one comes back

the double way diode, that's pretty funky stuff!


I'm using DesignWorks Lite for schematics, and it's pretty good for me so far...

[flipper_md]

just a little follow up on this

Finally ,I had to order 4.5V relays cuz order 5V we're not stock.
By time things arrived, I spoke with a few people and one told me that some relays were designed to be driven by IC, without anything special requd for protection.

I then decided to give it a chance, and it work! First without a bi-color LED on the pins of the coil, but this would take to much power and only the led would light up.
Removed the led, relay started switching, and kept going

since then I've being debugging/coding for a while, and no problem to report, for the relay.
Coding is another challenge

relays PN is AGN2104H

[Pic_User]

just a little follow up on this

Finally ,I had to order 4.5V relays cuz order 5V we're not stock.
By time things arrived, I spoke with a few people and one told me that some relays were designed to be driven by IC, without anything special requd for protection.

I then decided to give it a chance, and it work! First without a bi-color LED on the pins of the coil, but this would take to much power and only the led would light up.
Removed the led, relay started switching, and kept going

since then I've being debugging/coding for a while, and no problem to report, for the relay.
Coding is another challenge

relays PN is AGN2104H

Hi Dom,

Glad to hear you are making headway. Thank you for the follow-up information. We are all on the learning curve of life.

It is good to get technical advice from knowledgeable people.
Always double check information, at least till you find out which information sources are reliable.

Always read the data sheet.
Always “do your home work” with the technical briefs.

AGN2104H Relay
4.5V nominal 6.75V maximum

If you look at the AGN2104H data sheet:
http://pewa.panasonic.com/pcsd/produ...pdf_cat/gn.pdf

For Cautions for Use, see “Relay Technical Information”.

That brings us to here:
Relay Technical Information (PDF:400KB)
http://pewa.panasonic.com/pcsd/product/re/rti.pdf

Countermeasures for surge voltage of relay control transistor
If the coil current is suddenly interrupted, a sudden high voltage pulse is developed in the coil. If this voltage exceeds the voltage resistance of the transistor, the transistor will be degraded, and this will lead to damage. It is absolutely necessary to connect a diode in the circuit as a means of preventing damage from the counter EMF.

In the Technical Brief, they are assuming you are driving the relay with a discrete transistor. If you are driving from a PIC then the “transistor” is really inside the PIC. The same precautions apply.

Hope this helps,
-Adam-