Open Ardbir - Open source platform for brewing process control and automation

[Sorcerers Apprentice]

Thanks pob, with the rims tube I need to ensure that the associated temperature sensor is permanently married to the rims heater element. It could be very dangerous if for example the temperature probe in an empty bk was inadvertently selected while the rims element was firing. The selector switches must select the ssr and the temperature probe at the same time. The original switch you linked to might suit but from experience they can be quite "clunky"in operation

[Leann ull]

I was also going to use in a 3v system but have decided that it's too fiddly and opted to do a single vessel now instead

[molc]

Well, could always build an electronic selector for the job, with some or gates to handle your logic. I find the electric circuits quite complicated when you want to do non standard things...

[Will_D]

In my day they were (and still are) called rotary switches [sometime make-a-switch].

They are a set of components: switch wafers and the mounting hardware to allow you to make up stacks of switch wafers to do whatever you want.

Typically there were a maximum of 12 positions on the wafer so you could get a 1 pole 12 way, 2p 6w, 3p 4w etc. You just needed more wafers to switch multiple circuits. They were used a lot in valve radios to change the frequency bands!

[Sorcerers Apprentice]

Cheers Will
I had been looking at these type. I could use one to switch ssrs and temp inputs simultaneously

6mm Dia Shaft 4P3T 4 Pole 12 Position Band Channel Selector Rotary Switch
http://s.aliexpress.com/mY3yUvi2
(from AliExpress Android)

[pjfrad]

Just as some background, DC voltage is much more severe on relay contacts than AC due to the fact that DC causes more arcing. Therefore when you are buying a relay it will have a lower switch current rating than if it was switching AC. So check the DC contact rating as it can be as low as 50% of the AC rating

Thanks for the reply.. this is a bit over my head...
Am I looking for something like this to swithc/power a 12v pump.

http://www.ebay.ie/itm/5V-12V-24V-10A-1-Channel-Relay-Module-Optocoupler-H-L-Level-Triger-for-Arduino-/131584267865?var=&hash=item1ea3089659:m:mDBIexHsWx7fhkZecRuGDqQ

Hi guys,  This has been a great thread.  I'm building a very similar single vessel system with the ArdBir, and it's almost all up and running except for one bit...  I'm doing something stupid I'm sure, but I can't figure out how to wire a relay, similar to the one linked above, to the pump output on the ArdBir and have it operate correctly.

Any help would be greatly appreciated.

[Sorcerers Apprentice]

Hello and welcome to the forum pjfrad, you should consider taking out a membership as the benefits far outweigh the cost.
Are you planning on using a 12 volt solar type pump or a 220v chugger type?

[pjfrad]

Hello and welcome to the forum pjfrad, you should consider taking out a membership as the benefits far outweigh the cost.
Are you planning on using a 12 volt solar type pump or a 220v chugger type?

Hi, thanks for the welcome.

I have a 12 volt DC pump.  If I power the relay from +/-12v and connect the pump to the normally open on the relay it runs fine, connecting it to normally closed means the pump doesn't run, which you'd expect.

I've tried several combinations of hooking up the wiring to the Ardbir to get it to activate the signal pin, but am not able to get it to switch they relay.  I'm testing by trying to turn the pump on and off in manual mode.

[Leann ull]

post a pic of the top of your relay most of them are 24-340V AC.

[pjfrad]

post a pic of the top of your relay most of them are 24-340V AC.

I don't have a pic handy, but here's a link to the relay I bought on Ebay.
http://www.ebay.com.au/itm/391273127391?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

I also updated my post above to make it clear that it was a 12v DC pump.

[Sorcerers Apprentice]

It looks like there are three connections on the low voltage side. Ucc is the positive Gnd is the negative and when you apply a 5v positive or negative to the In contact the relay should energise. (Depending upon whether it is a pnp or npn type) This relay is designed to be operated by transistor switch rather than the way you are trying to operate it. To test the operation connect the plus and negative to Ucc and gnd and link the positive connection to the in briefly to see if the relay operates

[pjfrad]

It looks like there are three connections on the low voltage side. Ucc is the positive Gnd is the negative and when you apply a 5v positive or negative to the In contact the relay should energise. (Depending upon whether it is a pnp or npn type) This relay is designed to be operated by transistor switch rather than the way you are trying to operate it. To test the operation connect the plus and negative to Ucc and gnd and link the positive connection to the in briefly to see if the relay operates

I did test this out, if I connect the Ucc and Gnd, and then connect the in to earth, the relay activates.  I tried connecting both the Ardbir's + and - to this pin but with no success.

Do I need a different type of Relay to make this work?  I got these relays because of what I saw in the link that I quoted in my original post.

So the more I think about it, is the problem because this is a low level trigger?  Is there a way to invert that, or do I need to buy a new relay with a high level trigger?

[kenmc]

This wee relay is designed to be tied high and low, and triggered via "IN", which controls the relay. The code for ardbir uses "low" for off and "high" for on for the pump, so there's no reason you can't tie VCC to 5v, Gnd to Gnd and IN to the relay port on the ardbir the ardbir should be able to activate the relay.

However, given that you say that the relay activates when connected to earth, you would probably need to play with the ground/nc/no contacts on the pump end of the relay so that it's behaving correctly according to what the ardbir is trying to do with the pump. it should be fairly easy to figure that out.

<edit>looking at the pic again, that's a 12v coil relay it seems, so it may need to be tied to 12v instead of 5v. be careful doing this, that there's not 12v going back into your ardbir as this will likely fry it! Personally i'd swap it for a 5v coil relay or put a diode into the IN line to be sure there's no voltage going back that way.

<further edit>
if you're mixing the 12 and 5 volt rails, you will need to have a common gnd too, else the relay won't be driven from the ardbir.

(for what it's worth, I don't have an official ArdBir board, but am fabbing one myself, so I'm not familiar with exact intricacies of the board you're dealing with, so take any advice under caution!)

[kenmc]

Ok I've just been looking at the connection manual for the open ardbir (https://www.dropbox.com/sh/96o6i39o50llama/AADOdbENIRJhRFbeGxB_ITF7a/All-in-One%20Board%20connection%20manual/All%20in%20one%20user%20manual.pdf?dl=0), and from what I can see, I've been talking crap.

The board looks like it uses a 12 relay coil as you already have. However it shows the connection to the wrong side of the relay board which doesn't help.

So here's what I suggest. Get a multimeter and measure the voltage across the +12 and 0v "pump" connector terminals on the ardbir board. If I'm right, these will switch between 12v when the pump shoudl be on, and 0 v when off.Also check that the 0v is indeed the boards' ground. If this is the case, then we're good to go.

the +12v terminal on the ardbir should be connected to the IN of the relay board, this is the switched trigger for the relay coil
GND and VCC should be connected to ArdBirs Gnd and 12v lines, probably easiest to take off a tap from the 12v input to the board for this.
This should get your relay activating when the ARDBIR tries to control it.
Now you just need to figure out whether you need to use GND and NO or GND and NC terminals at the other end of the relay.  (bear in mind that you will only connect the positive side of the pump wiring through the relay, like you would a switch, not ground and +12v.

As far as I know that should all work fine, but like i said check the values on the terminal using a multimeter before you do anything.

I didn't realize that the official ardbir produced 12v output switches for the relays. My board is running at 5 volts everywhere.

Sorry for any confusion my previous post may have introduced.

Diagram attached hopefully should clear it up

[darren996]

My relay arrived yesteday, so havent wired it up yet.
I found this llink that explains how various types of relays work, mght be of use ..

http://www.forward.com.au/pfod/HomeAutomation/OnOffAddRelay/index.html