A clean way to extend a cable (3 wires)

Hello!

First of all I'd like to say that I know this is a very basic topic, maybe not worth an own thread. But I'm quite new to electronics and I want to finish my first arduino project best possible. Everything works as it should (I built some kind of weather station), the last thing I want to do is to extend the length of the temperature sensor's cable.

I'm using adafruits pre-wired DS18B20 sensor whose cable length is about 3ft/90cm (High Temp Waterproof DS18B20 Digital temperature sensor + extras : ID 642 : $14.95 : Adafruit Industries, Unique & fun DIY electronics and kits). I need another 2ft/60cm in order to get a total length of 5ft/1.5m.

  • From my understanding and from a technical point of view, increasing the length of the cable should not be a problem at all since the DS18B20 is not an analog sensor (unlike the lm36 etc.), but a digital one. Am I right with this assumption? As I already mentioned, I just want to extend the cable by a few ft/cm, not much at all.
  • My main question is: how can I extend the cable in a clean and easy way? I'm especially interested in how to make the junction/interface between the wires of the existing cable and the wires of the new one. Unlike the original product, the extension does not have to be waterproof since this part of the cable is used indoors. But it should be a solid solution so that the cable does not fall apart when touching it. I'm also interested in what cable I could use for the extension. Are there any best practices for easy but solid results? I thought of using a 3 wire cable with female connectors and putting tape around the junction, but perhaps that's a bit too naive and sloppy.

From a schematic point of view, the result should look like this:

(pre-wired DS18B20 + cable) -> (extension cable) -> (breadboard + arduino).

Thanks in advance! :slight_smile:

edit: I apologize for my english, hope you can read it

Hi,

I have a DS18B20 sensor on my roof - it's at the end of a roll of cable that's normally sold for burglar alarm installations. The sensor itself was one of those weatherproof types and the connection was made by soldering the wires, covering each in heatshrink then adding a large heatshrink over the entire connection. At the Arduino end, I used a 3.5mm audio jack to plug the wire onto the enclosure, with a 3.5mm stereo socket completing the connection back to the Arduino sheild inside the enclosure.

Hope this helps,
Geoff

Well, you can get cable splice connectors at Adafruit and elsewhere that don't need soldering. Make sure the splicer is made for your cable size (a lot of them are for much thicker wires): Cold 2-Wire Splice (UY) - 10 pack : ID 1496 : $2.95 : Adafruit Industries, Unique & fun DIY electronics and kits

You could use a standard connector, such as the 3.5mm stereo audio connector mentioned by strykeroz, but you could also use 2.5mm stereo audio connector, 4 wire US phone cable (RJ-11 or RJ-12), or ethernet cat5e cables (RJ-45), and get a standard cable to cover the length you need.

You could also solder the wires together and put heat shrink around the cables to prevent causing a short.

There are also barrier strips that you screw in wires.

If you live in the USA, and are just buying a few connectors, most Radio Shacks have some filing cabinets in the back that have all sorts of components. If you are lucky, your RS will have at least one employee who is familiar with the cabinet and its contents. Generally, RS prices are high if you are buying multiple components, but if you need something at 8:30pm, it can be useful.

Lets see, for the standard connectors what can we find:

strykeroz:
the connection was made by soldering the wires, covering each in heatshrink then adding a large heatshrink over the entire connection.

This.