LinkMeter v2 Homebrew BBQ Controller - Part 1


 
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Originally posted by Kyle Christensen:

Thanks for the info! I just ordered up the mouse/digikey/polou parts list on the Wiki and some IC sockets, and have a 3.1 board on the way. Once I've had time to put the board together I'll see about getting a button board printed up or depending on time see about etching my own (I've always wanted to try that.)

I haven't ordered probes yet as I was unsure as to actual probe usage. I haven't stumbled upon mention of how many most people run, or probe placement.
Click to expand...

As for probes, you have to have at least one for the pit. Most people have two, one for the pit and one for the chunk-o-meat on the pit. If you want to monitor more that one chunk-o-meat you will need more probes.

The button board is a pretty easy board to etch, but it is easier to just build it like Bryan did using an old CD as the board and just soldering the resistor leads together. Etching it is fun
icon_smile.gif
I use muriatic acid and hydrogen peroxide.

good luck,
dave
 
I usually have one probe in the dome that I use as the pit probe, then one per meat, which is one or two. For ribs I don't use a meat probe so I sometimes will stick a probe at grill level just for more data.

I'm still most confident with making things on perfboard, but when I etch my own I also use muriatic acid and hydrogen peroxide. I haven't gotten perfect at the toner transfer part, so I end up transferring it like 5 times before I get it right.

I have found 1 problem with the v3.1 board and that is that if you use a vertical pinheader for the probe jacks and use a whole rectangular shroud on the connector wire, the wires jam up against the top of the WRT54GL case, which seems suboptimal.
 
@Duston Anthony: Do you still have a board left? I'm going to start a list in the first post of people who have spare v3.1 boards they're looking to sell.

@Dave: If you still see the oscillations in your graph with a load, I'd try increasing PIDd. pidd=2.0 is the default. Try maybe 4.0 and see what it looks like or even 10.0. 2.0 = for every degree the temperature has changed in the last ~30s, artificially adjust the setpoint 2.0 degrees in the opposite direction of the change.

EDIT: Also this oversampling thing is pure genius. Really absolutely sweet, Dave. Not only does it improve the temperature you see, especially at lower temps, it should also allow the PID to track better because one ADC step was like was like 0.3-0.5F at grill temperatures. Once I fix up the LMR code I'll get this into the git repo.
 
Bryan,

Is there a way to save my probe configuration and be able to restore it?

I'm planning on using the ET-732 1Mohm probe for my pit, and the ET-73 probes for the food. This means I need to have a custom setting for pc0. I'd like to be able to save the configuration, then be able to simply re-load it after a new flash.

thanks,
dave
 
Brian I have atleast 4 more boards avaliable right now. I also can not seem to find a switch for the reset switch. Everyone seems sold out at this time. Is there anyway to not install one on the V3.1 board and it still work?
 
I am trying to compile the heatermeter code using the new Arduino 1.0 software and it keeps giving me a bunch of crazy errors. Has anyone seen this or know a way round this so I can upload a sketch to my new V3.1 board.
 
I'm using version 0023 without issue. Maybe you could download the version and use it instead?

dave

Originally posted by Duston Anthony:
I am trying to compile the heatermeter code using the new Arduino 1.0 software and it keeps giving me a bunch of crazy errors. Has anyone seen this or know a way round this so I can upload a sketch to my new V3.1 board.
Click to expand...
 
Ya I have been using version 23 but I like the new option in V1. that allows you to pick what programmer to use just by pressing the shift key before you hit upload.
 
Originally posted by Duston Anthony:
Ya I have been using version 23 but I like the new option in V1. that allows you to pick what programmer to use just by pressing the shift key before you hit upload.
Click to expand...

Gotcha
 
Originally posted by D Peart:
Is there a way to save my probe configuration and be able to restore it?

I'm planning on using the ET-732 1Mohm probe for my pit, and the ET-73 probes for the food. This means I need to have a custom setting for pc0. I'd like to be able to save the configuration, then be able to simply re-load it after a new flash.
Click to expand...
No there's no way to back up your configuration currently, I've still got that on my plate. Your probe configuration is saved between HeaterMeter flashes though, so you shouldn't need to restore anything. This assumes you don't do a chip erase using an ICSP or anything though. You can just make a script or something like `lmclient LMST,pc0,A,B,C` if you're doing that, or optionally if you're using an ICSP you can store the eeprom data and reload it as part of your avrdude command line.
 
Originally posted by Duston Anthony:
Brian I have atleast 4 more boards avaliable right now. I also can not seem to find a switch for the reset switch. Everyone seems sold out at this time. Is there anyway to not install one on the V3.1 board and it still work?
Click to expand...
Yeah you can just leave it off. If you want to reset the AVR just short one of the two pairs of holes from the left side to the right side (the smaller dimension of the board, not the axis that has S1 printed on it). The switch isn't necessary for normal operation and really only needs to be pressed once for the initial flashing, which you can do with just a piece of wire.

I am trying to compile the heatermeter code using the new Arduino 1.0 software
Click to expand...
Yes HeaterMeter still uses 0022. I'm kinda mad about the direction they're off on and was hoping they'd see the light before releasing 1.0 but I'm guessing I'll have to accept it.
 
On the V3.1 board what is the voltage from ground to the LCD backlight suppose to be? I am getting 2.5 volts. I do not have the LCD pull down resitors or the other resistor that can be put in to lower the voltage. I believe this is R7.
 
Originally posted by Duston Anthony:
On the V3.1 board what is the voltage from ground to the LCD backlight suppose to be?
Click to expand...
Assuming you mean pin 15 vs ground it should be 5V. If you're measuring pin 15 vs pin 16, that could give you 2.5V maybe although it is actually switching between 5V and floating 500 times a second. Pin 1 on the LCD, PROBE, or FTDI connectors, or Pin 2 on the POW connector are some readily available ground points.
 
All,

I know we have the coefficents for the ET-73 probes but I email the maverick folks to see if they could provide us with their docs for both style of probes.

Darren over at Maverick provided me the data sheets for the ET-73 they have on file. Don't know if anyone wants to run the numbers on it.

ET-73 DataSheet

I also emailed him back to see if there was any info he had or could he try and get for the ET-732 probes.
 
That is what he sent me as well. I did find codes for the ET-732 that work really well. I posted them up above:
http://tvwbb.com/eve/forums/a/...801049926#5801049926

Darrin from Maverick said he didn't have them for the ET-732 so I went and found one that matches very well.

dave

Originally posted by M Rochford:
All,

I know we have the coefficents for the ET-73 probes but I email the maverick folks to see if they could provide us with their docs for both style of probes.

Darren over at Maverick provided me the data sheets for the ET-73 they have on file. Don't know if anyone wants to run the numbers on it.

ET-73 DataSheet

I also emailed him back to see if there was any info he had or could he try and get for the ET-732 probes.
Click to expand...
 
@D Peart: Great work on the ET-732 probes and the oversampling! I look forward to seeing these improvements in a future build.

In any case, in the course of your experimentation with the ET-732 probes I realized that I am actually using ET-72 probes. I had the probes before I started building the Heatermeter. I didn't really check to see which model probes I had because I assumed that the steinhart coefficients were the same for the ET series probes. I guess it is likely that they are different from the ET-73 probes given the fact that the ET-732 probes are different. Has anyone asked for the datasheet for the ET-72 probes? If not I will when I get home from vacation. Maybe I can repeat the process you went through with the ET-732 probes. Seems like you learned a lot and it would be a beneficial exercise. I have been suspicious of the readings on my probes but haven't had any time to troubleshoot.
 
I'm confused now. Are the original probes from the ET-72 or ET-73? My originals were from a Willams-Sonoma branded remote thermometer, the first set I ordered was ET-72, but I can't remember what high-heat probes I got. Probably ET-72 6ft. All of these read the same within tolerance. I assumed they used all the same for every model but Dave proved me wrong on that.

@D Peart: Regarding the saving of configuration, I don't know if you are aware but you can just put your config in a URL and make a bookmark for it. Just put together all the parameters separated with & like:

http://192.168.2.2/luci/lm/set...Food%20Probe1&lb=128
<pre class="ip-ubbcode-code-pre">
User root setting 5 values...
username to root = OK
pc0 to 5.3612e-4,1.91532e-4,6.557e-8,1.0e4 = OK
lb to 128 = OK
password to = OK
pn1 to Food Probe1 = OK
Done!
</pre>
Disregard the username and password items, because it asks you to log in when you click the url, so they are added on. One thing to watch out for is that "+" needs to be replaced with %2B, but the web browser will often fix up all the rest of them for you. You can set as many items as you want because URLs can get really big.
 
Originally posted by Bryan Mayland:
I'm confused now. Are the original probes from the ET-72 or ET-73? My originals were from a Willams-Sonoma branded remote thermometer, the first set I ordered was ET-72, but I can't remember what high-heat probes I got. Probably ET-72 6ft. All of these read the same within tolerance. I assumed they used all the same for every model but Dave proved me wrong on that.
Click to expand...

The long story...I purchased a ET-72 remote unit from a kitchen supply store (http://www.maverickhousewares.com/et72.htm). I bought an extra probe with it. The extra probe was broken out of box and I wasn't very careful with the probe that came with the ET-72 and it wasn't reading correctly. I thought it was the quality of the probe so I wrote Maverick to complain. They explained to me that if you close the probe in the smoker lid or door it can cause off readings and even break the probe. They sent me two ET-72 probes free of charge even though it was probably my fault that the one wasn't reading correctly. The people at Maverick are really great!

Soooo I know they distinguished between ET-72, ET-73, ET732, etc probes when you order replacements but I am not sure how the probes differ between models. Perhaps we should ask Maverick this question...
 
I am building the RF remote node on a V3.1 board. What needs to be populated on the board to get it to work. I assume the probe portions and the RF portions. Does the LCD stuff need to be populated?
 
Originally posted by Duston Anthony:
I am building the RF remote node on a V3.1 board. What needs to be populated on the board to get it to work. I assume the probe portions and the RF portions. Does the LCD stuff need to be populated?
Click to expand...
That's a good question. The remote node is a different design but it is possible to make a v3.1 board work, in a less than optimal way. First of all I want to make sure it is clear the remote node is a transmitter back to the base station only. It only sends temperature data back to the LinkMeter. If that's ok then we can begin.

No the LCD and shift register and all those parts don't need to be populated. Heck most of the board doesn't need to be populated. Let's see, you'll need the 3.3V regulator, but not the SOFTRST circuit, the button circuit, the serial divider (R2, R21), or the fan control circuit. If you're planning on running it from batteries, you can probably run it on a 9V, but I'm not sure how long.

I can give you more details if you're still interested.
 
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