Meat thermometer, what kind of sensor is in there?

I measured the same on a kitchen-thermometer probe I have. I think the whole thing with probe is ~$14 at Walmart.

Close to this:

Thermistors.

Cheers, James Arthur

There are a bunch of different betas and not always measured at the same temperatures. The bulk of them seem to have originated from a single Japanese company back when- they teamed up with another Japanese semiconductor company to make the first low cost highly accurate battery powered temperature meters.

Try a 10K with beta 25/85 around 3435 (you can replace the sensor with a resistor or two of known value to confirm- 10.0K should give 25C display and 3.02K should give you 60C. They change about -3%/degree C so you don't have to be all that accurate.

I see a couple bead type with 4cm leads at Digikey for cheap.

--sp

On Dec 19, 2016, Joerg wrote (in article ):

Thermocouples with teflon insulation and yellow plugs are good to ~500F (the wire) and maybe 300F (the yellow plug), so sterilize the sensor by boiling the entire probe assembly in a pot of water. Scrubbing not required. Given the low impedance of a thermocouple, the sensor will work even if soaking wet.

The standard problem with sensors in house ware level temperature sensor probes is mechanical - the wires break from flexing. This is true regardless of sensor type, thermistor or thermocouple.

My favorite vendor for kitchen thermometers is ThermoWorks - while you will pay for the probes, they seem to stand up to reality fairly well. (The ThermoPen has revolutionized cooking in my home.)

But given that you have suitable handheld multimeters, I?d just buy and use industrial-grade thermocouple probes.

The next level up is 100-ohm platinum RTDs used with a Kelvin (four-wire) ohmmeter. Again, there are industrial probes available that use this kind of sensor. I?d venture that this would be overkill, unless one already has the ohmmeter. But it will work despite ratty cabling.

Joe Gwinn

As I mentioned it is not about local measurement. Then I could just use a steam gauge as most home brewers do. Drill a hole into the pot, mount, then never again worry about batteries and whatnot.

I want to be able to work in the office while keeping a "remote eye" on things downstars. Only works via RF.

Not a safe option with beer. If you leave gunk on there it'll still work, even though more sluggishly. However, in the end you must cool the wort down very fast and monitor the temperature to make sure the maximum yeast pitching temperature isn't exceeded. At that pont the wort has no alcohol yet and is very susceptibel to contamination. Which is almsot guaranteed to happen with a dirty sensor.

Well, I need a radio link from the brewing dungeon downstairs into my office quite far away.

Sure, and that can also use thermocouples. But then I have another project, having to write a SCADA routine, ferry the data into a transmitter, build a receiver I can carry, and so on. Add to that a super-cramped brewing dungeon where even placing a small tablet would be a challenge and it all becomes a pain. A regular wireless meat thermometer works well. If the probes hold.

Some day I will. I think one needs an account there.

Tried it: 10k results in 214F displayed. 47.5k results in 137F. Looks like some non-standard version to me.

I do, in fact I can set it up to a another device that can act as a thermocouple and scale it.. I can also set it up to understand current transmitters etc.. Its a nice feature, along with its 6 diggits.

Jamie

On Dec 20, 2016, Joerg wrote (in article ):

I would have thought that being boiled for a while would clean the gunk off, and sterilize it as well. There is no harm in scrubbing, so long as the business end is heavy enough to survive scrubbing.

If not, use a TC encased in a stainless steel tube, and scrub away. I imagine that this is what commercial brewers use.

How far is that, in meters? TC wire is pretty cheap, and robust. Like bell wire.

Be careful to get the right kind, usually Type J or Type K, whatever your multimeter will accept. Because no current flows, there is no voltage drop, so the wire diameter is chosen purely for mechanical reasons.

One can also get industrial ethernet sensors from Omega Engineering, who sells retail over the internet. Automation Direct may also have suitable units. Maybe they even have WiFi, but WiFi isn?t really suitable for a factory - too much EMI. Don?t use Blue Tooth - legs far too short.

Joe Gwinn

On Dec 20, 2016, Joerg wrote (in article ):

Look wireless thermometers intended for low-and-slow smoking of meat: For instance: . .

Joe Gwinn

On Dec 20, 2016, Joerg wrote (in article ):

One does need an account. I have one, and have had no problems. Very much like Amazon, with their own version of PayPal called AliPay. The big problem is that it can be hard to tell exactly what one will receive. But it?s cheap enough one can afford a lot of misses.

Joe Gwinn

In general that is true. However, if you have crusty stuff on there and while the wort cools it falls of then any still living bacteria that were encapsulated can be released. It doesn't take much to spoil a whole batch.

True. Though I do need that radio link and that restricts me to meat thermometers unless I am willing to start yet anothe science project.

About 100ft. The wire would go through some hightraffic area, not good. Plus I need to carry it between lab, office and shop area when working on prototypes.

I try to get meat thermometers that operate on 433MHz. In a pinch I can always make a better antenna or use an off-the-shelf one for UHF TV.

I know :-)

I've got something similar but the probe just broke.

Can they work with a regular credit card and is the credit card info safe there?

No account needed. I do have an account, but do not have my credit card i nfo on the account. Having an account lets you look at past orders and hav e several shipping addresses on file. So I can have things sent to me , or my son, or my niece, without retyping the shipping data.

Some things are cheaper on Ebay, but lots of stuff in cheaper on AliExpress .

Dan

Yes it works with a regular credit card. And you can have the credit card info stored there, or you can opt to not have them store the credit card da ta. Pretty much like Ebay, but the default in Ebay is to store the credit card info, and the default on Ali is to not store it.

Dan

The problem is obvious. You're using a meat thermometer, when you need a beer thermometer.

Where do I send the invoice?

So get one of those cheap wireless cameras and aim it at your gauge.