Nope - you will need to spin one up (mosquitto is open source and the most common). Run it on the same box as openHAB. Plenty of tutorials about how to set it up, relatively straightforward for the simple case.

I want to monitor from an Android phone so will need to find an Android broker app, then?

If you are using openHAB then just view the temp on that.

Ah, thanks, thought I needed openHAB AND a broker. 

Hardware shipped so on the way!

Cheers.

You do need a broker. The broker is where the sensors *publish* to, at a specified topic (e.g. sensors/living/temp), then openHAB *subscribes* to the same topic and consumes the data. 

Just came across this - https://play.google.com/store/apps/details?id=net.routix.mqttdash - looks like it might be perfect for you to visualise your sensor readings without having to worry about openHAB etc. Don't think it has any alerting as such but it might be a good starting point to get your sensors and broker up and running?

Thanks, SB. I saw that when searching Google Play. Well worth a try.

Still confused with the broker thing, though. If a broker is necessary, where is the broker installed if this app (or openHAB?) is used? Do I have to install mosquitto on a networked Windows PC?

Sorry, but can't yet get my head clear on the broker bit in my proposed setup!

Yes - the broker is a 3rd party service you need to have running on your network somewhere. On a RPi or NAS perhaps. Then your sensors publish to the broker and your consumers (i.e. the MQTT dashboard app or openHAB) subscribe to it. Plenty of online tutorials and guides about MQTT and brokers etc.

linw:

 

Thanks, SB. I saw that when searching Google Play. Well worth a try.

 

Still confused with the broker thing, though. If a broker is necessary, where is the broker installed if this app (or openHAB?) is used? Do I have to install mosquitto on a networked Windows PC?

 

Sorry, but can't yet get my head clear on the broker bit in my proposed setup!

 

linw have a read of http://www.makeuseof.com/tag/openhab-beginners-guide-part-2-zwave-mqtt-rules-charting/ it's what I used to get mqtt working.

Or you can use an online broker like adafruit.io if you do not want to have to expose your one to the internet to see the values when you are off site.

Thanks again for added info, guys. I have seen that site, Blanch, and will have another read.

Won't need offsite access for this project, rich, but did see adafruit project. Looks interesting. 

Have to do more study and hope the hardware turns up soon. 

Cheers.

Progress report. The hardware turned up 3 days ago. Only 8 days since ordering which I reckon is darn good.

Having fun playing. Currently have it working with the DS18B20 shield and the One-Wire code. Big weakness with that shield is that it gets heated by the D1 Mini till around 25deg.

Of course, the first prog was Blink!

Next will get it going with the probe version of the DS18B20. Shouldn't be too big a step one hopes.

Have mosquito running on my PC and can see it listening on port 1883.

Big steps coming soon but I am having a lot of fun for a stupidly small amount of money, and getting to learn the Arduino prog language is fun as well.