Retrofit RJ11 connections


For those of us who already have DS1820B temperature sensors fitted to our rigs we are going to need to crimp RJ11 connectors to the end of any leads to make them compatible with the new Spark based units.

Could you confirm which pins/terminals of the RJ11 are being used for corresponding connections of the sensors GND, VDD, DQ? An image would be really helpful. Those with sealed probes with wire colours might need a colour coded wiring description.

I know you want to get away from DIY connections as they causes issues but it would seem crazy for those upgrading to get new probes simply for the connections.

I have a crimping tool and am happy to order the connection plugs off eBay (you can get like 10 for £1) but you might want to sell them too?


Will definitely post that info when I get back from MonkiGras.

Looking into the RJ12 Socket, from left to right:

RS485-A, 12V, 5V, GND, OneWire, RS-485-B

But I agree this needs pictures.

Thanks Elco,

Interesting to see all terminals being used. For some reason I imagined only three being used.

With all pins in use I suppose the options are crimping a plug to existing cables or modifying a ready made RJ11 cable to suit.

Will let you know how I go and look forward to photos.


Elco, how many mA can brewpi handle over that 12v line in the rj12

To use OneWire you would only need to connect 3 pins and you can use RJ11 instead of RJ12.

The 12V is fuse protected at 1.5 A.

Was just wondering if the brewpi could handle small voltage devices over the 12v line. Like having a onewire connected fan that only needs to have single rj12 connection. Using a low mA pc fan as an actuator and not having to bring supply voltage to the fan makes it modular.

Yes, a 12V fan is usually below 1.5A.

I will design a pump control board, which can also be used to PWM a fan.

Cool. What kind of pump will use pwm?

DC voltage pumps. I am going to sell 2 pumps:

12V, max 3m head, food grade plastic pump head, 11.5 LPM

17V, max 4.5m head, stainless steel pump head, 22 LPM

The 17V pump will be modified for me to have a speed control input, so it will adjust its power to match the speed.

Ok. My 12v pumps have some internal circuitry that doesn’t work with pwm.

Would it be possible to retrofit the connections on the new Spark Sensors to RJ45?

I do not see your intended purpose here.
The connectors on the BrewPi Spark are RJ12 (6P6C): 6 pins, 6 connected. This is also compatible with RJ11 (6P4C), which has the same form, but does not connect the outer pins.

RJ45 is 8P8C and has a bigger plug.

My control panel will be on the bottom of my brew stand so the connections need to be somewhat water resistant, so I found the Ethercon from Neutrik for a decent price. The only issue is they only sell them in RJ45 Connections, but they make the control panel look great!

For my control panel, I just used a cable gland. That’s really waterproof, you just cannot unplug it.

RJ45 kinda works: you can plug an RJ12 into an RJ45 jack. The downside is that the the outer pins of the RJ45 jack are pushed down by the body for the RJ11/RJ12 plug. You are not supposed to do that and it will probably be bad for the longevity of the socket. But it will probably work :wink: