need ideas on what connector to use to connect temp probe to arduino project box

I need some ideas/suggestions on how to connect a temp probe to a sparkfun project box.

I am considering either a stereo plug/jack, or a molex 3pin wafer connector like

any other ideas?

what are the constraints/requirements?

must it be waterproof?
must it be replacable from the outside?
must it be ....

I am using the sparkfun case, so it is not waterproof.
I am looking for connector ideas, so It needs to be detachable, for maintenance.
I'll be needing 4 connectors altogether, two 2pins, and two 3 pins.

do you have any idea/suggestion?

Think you should look for a connector that can be mounted in the outside of the box, so you don't need to open the box every time you disconnect.

What sensors do you use?
How many "contacts" do you need?
Can the sensors be "daisy chained"? e.g. they all operate on one bus (that means you could do with one connector on the box)

I am doing stereo plugs for mine and it works well. It is pretty common in commercial products as well. If you do 1 connector per probe then you don't have to plug in probes if you don't need them all always.

yeah I'm leaning towards using stereo connectors as well, like this. I can go as high as 4 connector plug, but it gets a little pricey at almost $3 just for one plug. I can get a set of 6 plug+jack for $4.50 for the stereo type.

rather than wafer connectors like this

I imagine it would be easier to drill a round hole than to cut a rectangular hole.

It's hard to find finished projects on the internet for ideas, I found mostly blogs of people's projects on breadboards. Just look under playground exhibition page and you'll see what I mean. :slight_smile:
Any other actual connector type suggestions from anyone? I just want to make sure I considered all options before I make the final choice.

RJ45 network connectors? Widely available, cheap as chips, and you get 8 conductors per connector.

Stereo plugs are a good choice. Cheap, rugged, and good for a whole hell of a lot of mate/demate cycles. They're also among the easiest connectors to mount on the outside of a case since they only need one round hole.

What type of temperature probe is it?

I use Molex plugs in a lot of my projects. In my experience, it's a bit of a hassle.

For one, I've had to change mating connectors twice because some particular part got discontinued, and I could no longer use the same headers on my 2-conductor plugs as the stash of 5-conductor plugs in my parts bin. Now I have a bunch of mismatched connectors. The new and old wire-side plugs use different crimp pins. The pins are made to be used with tools that cost $100s of dollars, but you can get away with pliers or generic crimpers, if you're not concerned about neatness. On top of all that, the parts aren't cheap, and I've broken a few of the locking tabs just with normal use.

You can use 0.1" male headers and IDC or crimp-pin wire connectors. You have some of the same issues (needing the insert pins), but they don't tend to change and are universally compatible with any other 0.1" male header.

Or, you can just go with the 3.5mm jack.

thanks for the replies!

I like the rj45 idea simply for the number of lines it can handle in one jack. but the challenge there is it has to be mounted on pcb.

another connector I just came across is the mini din connector, which goes up to 8 pins, plus the shield for ground.
this one looks promising.

8 pins plus ground can replace the 4 stereo jacks I need. But I think separate connectors may still be better so individual probe can be unplugged for maintenance.

yes the 3.5mm stereo jack advantage is it is panel mounted then just run wires to the arduino. I can probably just solder one end of a jumper wire to the jack and just stick the other end/pin into the arduino female header.

PeterH, temp probe is as shown in the picture in first post of this thread, its your generic DS18B20 waterproofed probe you can get from sparkfun for $9.95+ shipping or from ebay. They seem to work fine.

ok, I have determined that using stereo connector is the best option.

Considering the temp probe is using OneWire, I can split the one stereo jack and can have two temp probes easily in case I need to expand to use two or more temp probes.

You do realize with 1-Wire products, you can daisy chain them, right? It's like a bus... they have addresses and can be enumerated at setup and individually polled and accessed in your loop.

I would recommend -- especially if you daisy-chain, but even otherwise -- that you run them with separate power and data lines. If you bus-power, there are additional precautions you need to (...well, SHOULD) take to ensure adequate pull-up, sufficiently fast transitions, and enough capacitance to avoid brown-outs during transmission and reset.

TI, and I think Maxim, have some good datasheets on circuit design for especially short or long runs, and compromises on daisy-chaining via star or bus topologies.

Also bear in mind that if plugging in with power on, stereo plugs momentarily short out the connections ..

PeterH, temp probe is as shown in the picture in first post of this thread, its your generic DS18B20 waterproofed probe you can get from sparkfun for $9.95+ shipping or from ebay. They seem to work fine.

Oh - so you aren't connecting a temperature sensor, you're connecting a serial device. In that case you can ignore any issues about terminal materials and just use any old data connector. In that case I'd use an RJ45 connector since they're cheap and reliable. You can get PCB mounted or case mounted sockets, and you can even use a standard patch cord as your cable if you don't feel confident about crimping your own connectors.