Coop door opener with 2 way 12VDC motor

Reloadron

Joined Jan 15, 2015
7,501
That relay is designed to mount on a PCB (Printer Circuit Board). When straight the pins should be in multiples of 0.1 inch spacing for a standard board. Unless they are to mm spec. Hows your soldering skills and creativity? Just make sure you get the pin out correct when you wire them.

Ron
 

Thread Starter

rfeyer

Joined Aug 24, 2014
126
So I could essentially get a fiberglass board and drill the holes to customize? Not sure if I would do that but it's good to know.
 

Thread Starter

rfeyer

Joined Aug 24, 2014
126
Thanx Ron,
I will go and get a few - unfortunate about RS - once they are gone I am stuck with online purchases as there are no other electronics component stores within 45 min of here :(

Rainer
 

Thread Starter

rfeyer

Joined Aug 24, 2014
126
Howdy,
had a little time to make some spaghetti - (wiring) and think I have it all wired up.
One caveat:
With all power off, no 12v or 5v connections tot he board, there should be NO continuity between the postive wire and one of the relay commons, correct?
I did connect an ohm meter between the 12Vwoer in connector on the board (without 12V PC connected) and the common of the 'Up' relay and did have continuity.
Back to checking my wiring, yes?
Hate to actually connect my MC and blow it up :)
Rainer
 

Reloadron

Joined Jan 15, 2015
7,501
There are ways could see continuity. I didn't look at all the paths but you could be reading through a relay coil for example depending on the contact positions. There are also a few transistors in the mix, things like that.

Ron
 

MaxHeadRoom

Joined Jul 18, 2013
28,619
So I could essentially get a fiberglass board and drill the holes to customize? Not sure if I would do that but it's good to know.
I haven't been keeping up with this thread, but I use a lot of prototyping Strip Boards from here. http://www.futurlec.com/ProtoBoards.shtml Half way down the page.
They are geared to 0.1" spacing components, but not usually a problem, there is a a few design software pgms geared to strip board such as LochMaster etc.
Max.
 

Reloadron

Joined Jan 15, 2015
7,501
Yeah, it could be just fine. When you take a resistance measurement always look at the possible paths of current flow. When we see a resistance there is always going to be a path for current flow. Sometimes that path is to be expected. There are, in this case assorted closed contacts and such, transistors and other paths. What I am saying is yes, it could be normal.

Ron
 

Thread Starter

rfeyer

Joined Aug 24, 2014
126
maxHeadroom,
I contacted The company and they answered that it is not a standard fit, go figure, though it did mention pic board in the write up. No prob, next time I will drill holes. Thanx for the link, though, looks like I can use stuff from there
Ron, thanx given the chance I will check paths one more time tomorrow

Rainer
 

Thread Starter

rfeyer

Joined Aug 24, 2014
126
And another question:
The MC I am using is a WebController 8.0; it's TTL output is 5VDC 30mA
In the schematic, the imput into the transistor is intercepted by a 1kOhm resistor. Is that needed since the signal from MC is only 5VDC with 30mA?
Rainer
upload_2015-2-10_7-47-31.png
 
Last edited:

tracecom

Joined Apr 16, 2010
3,944
And another question:
The MC I am using is a WebController 8.0; it's TTL output is 5VDC 30mA
In the schematic, the imput into the transistor is intercepted by a 1kOhm resistor. Is that needed since the signal from MC is only 5VDC with 30mA?
Rainer
View attachment 80253
Yes. The 1k resistor is there to limit the base current to the 2n2222, and protect the output of the uC.
 

Reloadron

Joined Jan 15, 2015
7,501
Have you considered the 2n7000 fet, they were designed with this purpose in mind, TTL/CMOS to power device.
Max.
That would have been a My Bad since I drew the thing up. Should I have considered it? Yes! Did I consider it? Sadly no and thus my bad and I am like 99% he has the transistors I suggested. :(

Ron
 

MaxHeadRoom

Joined Jul 18, 2013
28,619
That would have been a My Bad since I drew the thing up. Should I have considered it? Yes! Did I consider it? Sadly no and thus my bad and I am like 99% he has the transistors I suggested. :(
Ron
They have usually been my first go-to since they first came out in the '80's, I usually keep a draw-full on hand!;)
Max.
 

Thread Starter

rfeyer

Joined Aug 24, 2014
126
Thanks all - this won't be the last of these projects, have another of the same to do and will consider the above fed.

So, why does the already low 5V 30mA current from the MC to the Transistor have to be further reduced? I am asking just so I understand,

Rainer
 

MaxHeadRoom

Joined Jul 18, 2013
28,619
Simply put, a FET is a voltage operated device rather than a current device such as a bi-polar transistor, IOW it does not impose a load on the source (micro).
Max.
 

Thread Starter

rfeyer

Joined Aug 24, 2014
126
TY MAx,
to the original queastion, though (#91) - and for my curiosity - why, in the schmatic, is it necessary to have a 1k ohm resistor in front of a transistor which is only receiving 5VDC and 30mA from the MC? Wouldn't the low output of the MC be small enough to drive the transistor without harm?
 
Last edited:

Thread Starter

rfeyer

Joined Aug 24, 2014
126
:)
I followed along until Hfe = lc/ lb
From there, I will have to continue reading my 'Electronics for Dummies' :)
I will take your words of course - but eventually I will understand this a little.
Do you all literally calcualte this each time, or, is it experience that makes you remember? Or, do some of the schematics programs help with this as well? I am amazed!
Rainer
 
Top