RioRand DS18b20

[HiImBrian]

I just picked up a couple RioRand DS18b20 temp probes and am realizing that they might have been a bit of an impulse buy :smack:. I've got a few questions for the electrically gifted users on this board.

1) These things read celsius. Is there any way to convert them to fahrenheit?
2) How the heck do I run power to these things?

Here is more info about the thermometers, but it's all way over my head!
http://datasheets.maximintegrated.com/en/ds/DS18B20.pdf

 

[SilverZero]

DS18B20 probes are what are known as Onewire devices. They take power (3.3v or 5v) over red, ground on black, and the yellow is the data line. Power can come from the Arduino or RPi, or from a dedicated DC adapter like an old Walkman wall wart. Every sensor has a unique 64bit address so you can connect a number of probes to the same data pin on an Arduino or a Raspberry Pi and they'll all be recognized separately.

As for C vs F, I think that's a software translation so it depends on what you're reading the data with.

I don't know much more than that but if you go through Fuzze's first post on his Cheap BrewPi thread you might get a better idea of how they are used. The Elsinore implementation is basically the same but the data is fed directly into the RPi.

Hope that helps get you started!

 

[FuzzeWuzze]

They will work fine, all ds18b20s are the same, the only difference is how they are made into a cable.

What project are you using them for? By default they always report Celsius, but the software, brewpi or elsinore has the ability to translate it to Fahrenheit.

You power them with the gpio pins on a rpi or arduino with the proper pull up resistor in place.

Knowing what you're using them for would help.

 

[HiImBrian]

Thanks guys. I think with a bit of googling and reviewing your responses with my EE buddy I might have a chance of making these work.

I would like to mount each displace into my rig so that with each brew, I can just toss the thermometers into each kettle and be able to view a live temp display at all times.

 

[RufusBrewer]

They are digital devices. Essentially they constantly put out a signal that says: (paraphrased)
I am probe #100 and reading 40° C
I am probe #100 and reading 40° C
I am probe #100 and reading 41° C
I am probe #100 and reading 42° C



You can have multiple probes tie them all together and they take turns broadcasting their status (again paraphrased)
I am probe #100 and reading 40° C
I am probe #200 and reading 35° C
I am probe #300 and reading 30° C
I am probe #100 and reading 41° C
I am probe #200 and reading 34° C
I am probe #300 and reading 32° C

You need a device that has a port that can receive and understand the message. Any software or program or app that can understand the message, will be able to convert Celsius to Fahrenheit. Easily.

 

[HiImBrian]

Oh boy...I was hoping I could somehow run power to these things and simply output the temp on the display. I'd rather not use some kind of "program" and keep this as simple as possible. If I'm stuck with reading celsius then that's not the end of the world. Is that a possibility?

 

[RufusBrewer]

What kind of device were you expecting to connect it/them to?
What kind of device(s) were you expecting to display the temperature?

As far as I know, there are not any Pids or temperature meters you can hook this type of to.

 

[HiImBrian]

http://www.amazon.com/dp/B00IYCBNUM/?tag=skimlinks_replacement-20

Maybe we're misunderstanding each other. The above link is what I purchased. I figured I could bring power to the black/red wires and then chuck the thermometer into my HLT to get a readout on the LED display. Am I missing something?

 

[RufusBrewer]

Sorry about that. I thoght you bought some probes and were looking for something to plug them into.

Back to the OP:

The spec on Amazon says Unit of measurement is Deg C. Unless there is a switch or button on the box I do not see, you are probably stuck in metric land. You learn pretty quick hiw hot XX deg C is,

Looks like there are a red wire and a black wire that is power into the box. Spec says 7-30 VDC.Very forgiving range of input power.

The probe looks to be stainless steel and then some sort of rubber/nylon/plastic stuff. Do you want an unknwnn material on a device not specifically made for contacting food, touching your water or wort or mash? Probably not. I advise you put the probe in a thermowell and then put the thremowell in your water and/or wort and/or mash.

 

[HiImBrian]

^Ahhh all that makes me feel much better about getting these things wired up! haha thanks

Also, very good point about the plastic coating. I'll have to figure something out about that. Probably end up buying/making a thermowell like you mentioned.

 

[FuzzeWuzze]

http://www.amazon.com/dp/B00IYCBNUM/?tag=skimlinks_replacement-20

Maybe we're misunderstanding each other. The above link is what I purchased. I figured I could bring power to the black/red wires and then chuck the thermometer into my HLT to get a readout on the LED display. Am I missing something?

100% No that is not possible.

These probes require a microcontroller of some sort to read their values. You cant just plug them into an LED, they need to be addressed and communicated to through software.

What your wanting is far from difficult, but it will require an arduino of some sort so that you can properly communicate with the probes and output what it returns to the LCD's.

If you look up Arduino OneWire DS18B20's there are tons of apps out there already, but you do have to wire the probes up properly with a 4.7k resistor, again theres tons of pages out there on how to DIY and you could probably figure it out in a day and only spend another $10 on a Arduino Uno, a 4.7k resistor and some jumper wires.

 

[Pkrd]

There is a F version available:

http://www.riorand.com/riorandr-0-3...ermometer-dc-7-30v-power-led-display-red.html

 

[RufusBrewer]

100% No that is not possible.

These probes require a microcontroller of some sort to read their values. You cant just plug them into an LED, they need to be addressed and communicated to through software.

What your wanting is far from difficult, but it will require an arduino of some sort so that you can properly communicate with the probes and output what it returns to the LCD's.

If you look up Arduino OneWire DS18B20's there are tons of apps out there already, but you do have to wire the probes up properly with a 4.7k resistor, again theres tons of pages out there on how to DIY and you could probably figure it out in a day and only spend another $10 on a Arduino Uno, a 4.7k resistor and some jumper wires.

Check out the link. The probe is hard wired into the display. Looks like it is potted and no changes can be made. Obviously there is some sort of processor inside the display.

 

[HiImBrian]

There is a F version available:

http://www.riorand.com/riorandr-0-3...ermometer-dc-7-30v-power-led-display-red.html

Dangit! yea, I already bought the C ones. Oh well, that's not the end of the world.

 

[FuzzeWuzze]

Yea, ds18b20's are simple ic's, they just wrapped it up into an actual product. The bare probes won't do what op wants without making his own.

 

[HiImBrian]

^Um I'm not really sure what you just said, but I actually think these probes will work with the right voltage applied to them. Take a look at the amazon link...they come with an LED "controller"

http://www.amazon.com/dp/B00IYCBNUM/?tag=skimlinks_replacement-20

 

[RufusBrewer]

Yea, ds18b20's are simple ic's, they just wrapped it up into an actual product. The bare probes won't do what op wants without making his own.

Dude,

I think you are confused by the model number. I know I was.

Look at what he is buying. He is not buying just a probe. He is getting a probe and display with a power input. It looks like it is all potted together and I assume there are the appropriate electronics inside the the display to turn the probe's serial data into numbers on the front of the display.

http://www.amazon.com/dp/B00IYCBNUM/?tag=skimlinks_replacement-20

 

[FuzzeWuzze]

Dude,

I think you are confused by the model number. I know I was.

Look at what he is buying. He is not buying just a probe. He is getting a probe and display with a power input. It looks like it is all potted together and I assume there are the appropriate electronics inside the the display to turn the probe's serial data into numbers on the front of the display.

http://www.amazon.com/dp/B00IYCBNUM/?tag=skimlinks_replacement-20

My mistake!

Just go find an old 9V or 12V wall wort you have laying around, chop the end off and solder or wire nut the two power lines together. If you dont have one i recommend Good Will, they have piles of power cords for a dollar or two each, rather than spending 20+ at Best Buy or something for a fancy one.

My old 12V pumps were powered off a old Gamecube power brick.

 

[HiImBrian]

^ Thanks I think I've got it figured out! I just built a stir plate and did the same sort of thing with a random power adapter and it's working great. I appreciate all of the help and guidance from you guys!