Temperature sensor for grill/smoker
Chuck Rice
Posts: 210
I am looking for a temperature sensor to measure from outside temp to 1000 degrees (I guess that a grill can get that hot), but with the best resolution at around the 100..250 degree range. I want to have the propeller measure the temp, then either send me a message to add more coals, or adjust the gas jet if I am cooking with propane (I often use both to smoke briskets). But all I am finding are room temperature sensors in plastic cases that would melt if the smoker got too hot.
Has anyone happened on a sensor with the propper range?
Has anyone happened on a sensor with the propper range?
Comments
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Grills can be more extreme than this.
If you are willing to rig up an op-amp circuit, you can also try using a thermocouple.· This is basically two pieces of wire, made from different metals, soldered together at one end.· Some of them can get REALLY hot.
http://en.wikipedia.org/wiki/Thermocouple
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Post Edited (Ken Peterson) : 5/16/2008 5:24:31 PM GMT
Parallax sells a thermocouple kit using the DS2760. Search of DS2760 on the Parallax website.
Bean.
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Did you know that 111,111,111 multiplied by 111,111,111 equals 12345678987654321 ?
www.iElectronicDesigns.com
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You might look at the Omega website for more options...
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The smoker I was thinking about making was going to use an electric hot plate like in Good Eats (Alton Brown's Show) titled Q. My thoughts was to use a uOLED-PROP and the uOLED-IOC for a control and display. A user interface would be provided with buttons to start a timer and set the desired termperature. The thermocouple would provide feedback about internal temperature. An appropriate output circuit (relay or solid state or similar) would be provided to turn on/off the electric plate. I think the first revision would just turn the plate on/off instead of trying to regulate it. That needs more thought though.
Good luck with your project Chuck.
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Timothy D. Swieter
www.brilldea.com·- check out the uOLED-IOC, an I/O expansion for the uOLED-96-PROP
www.tdswieter.com
One little spark of imagination is all it takes for an idea to explode
Attached is the project. Feel free to use and abuse it. And enjoy a slow cooked brisket!
just a quick idea as posted out on a brainstroming,
how about using a small motor with a gear mechanical connected to a standard handdriven propane-valve?
best regards
Stefan
Yes, I have been thinking about that, but it would need to be failsafe. If something went wrong and it lost power, it would need to close the gas off. That means a strong spring and a strong motor. So I am still thinking about ways to do it.
as there is everytime a border where human beeing starts to be responsible. (which camping-gas-installation that uses rubbertubes
is automatic secured against cutting the rubbertube with a knife or disconnecting the grill from the tube ?)
I like to suggest more ideas. If the ideas are not useful themselves maybe they can be inspiration for new and better ideas.
How about a emergencybattery that delievers electricity for 10 Minutes to close the valve. And giving alarm about normal power failure
from one of these superloud beepers of a smokedetektor ?
The propeller could watch for battery-voltage still OK and normal powersupply OK. In case of a failure a normal relay as an "OPENER" contact that closes on
lost of power connects the battery to the beeper.
How about using a servo to have enough force to turn the valve ?
Camping-gas cooking stoves have a temperature sensor that has to be hot to keep a valve opend (by heatextension of a closed gasvolume)
If you heat this sensor electrically from the same powerline as the propeller-powersupply and the propeller drives a normal relay "opener"-contact
in serial to the electrical heating of the sensor. The sensors would become cold if the software fails and/or if the power gets lost.
I don't know the prices of these sensors maybe this is a cheaper way to do it.
Or a complete different way
cheers
Stefan
although the price is really 22.60 when you put it in your cart.
This looks like it would work. It is a high pressure valve, but I
assume that it would also work at low pressure. Does anyone
know more about Propane connections and safety? I do not
really want to earn a Darwin Award.
Flames and gas and electrical safety design is a big deal and very involved. I hope you don't earn a Darwin award either! The vavle you metnoiend, it looks to be on or off, not analog. To control the flame you can control the gas but also the oxygen.
I want to do a project similar to yours, but I am going to use electrical heating elements because they are easier to control. I watched a Good Eats episode once on the Food Network. This is Alton Brown's show. The episode was called Q and it was about BBQ (of course). Alton made a BBQ smoker out of flower pots and an electrical hot plate. There have been several peopel on-line who have also made similar devices, here is one: http://www.ntscblog.com/2005/07/little-brown-egg-i-condo-q.html
I thoguht I would use a uOLED-IOC and a thermocouple and solid state relays in the design. The OLED display would show the current temp and desired temp. Maybe it would also display cooking time and stats from other sensors. The data could be logged to the uSD card for later analysis (to get that perfect Q). The solid state relays would control the on/off of the hot plate. I figured a generic version of hardware could be made so that an electric smoker could be made or the same hardware setup could be used to make a reflow oven with some modifications to the firmware.
Please do share pics of your design!
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Timothy D. Swieter
www.brilldea.com·- uOLED-IOC, RGB LEDs, TLC5940 driver PCB
www.tdswieter.com
One little spark of imagination is all it takes for an idea to explode
It may give some ideas and provides links to used components.
regards peter
I went ahead and ordered the solenoid. We will see what I get. I knew that it was an on/off switch. I am thinking about one of two paths at them moment.
First, I could use the on and off to heat fire bricks and a water pan. When the temperature is below a set point (say for example, 170 degrees F), it turns on, heating the brick. When it gets above a set point (about 180), it turns off and the bricks and water radiate the heat till the temp drops again. This would require a pilot light or electronic ignition to start.
The other way would be to use the solenoid to act as the safety-shutoff, then use a servo connected to a valve to control the flame size. That way in case of a failure the solenoid would close shutting off the gas. With a loss of power, the solenoid would snap shut. With a flame blowout, the thermocouple would detect no heat and the propeller would de-energize the solenoid and sound an alarm.
Peter, thanks for the link! Lots of info there!
Your second method is interesting and I like the safety aspects.
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Timothy D. Swieter
www.brilldea.com·- uOLED-IOC, RGB LEDs, TLC5940 driver PCB
www.tdswieter.com
One little spark of imagination is all it takes for an idea to explode