Devils Advocate: Mega2560 or MB/DB combo


 
For me, the wireless probe setup is the way forward. Stripping the temp hardware from the head unit and pushing it to the remote makes a ton of sense. Especially when you can then permanently install the LMremote electronics package at the device being controlled at a relatively low cost. Keep the expensive stuff safe and out of the weather.

But assuming that you can get 4 probes + fan + servo working via RF, how hard would an RF signal strength readout on the LCD be? Or an alarm script that sounds when signal is lost?
 
It is without a doubt not the way forward, in fact I'd consider it a major step backward. I find the idea boggling because I can't understand how the current wifi interface doesn't do something that the RF interface can do, and does it more reliably.

The RF strength is shown on the web page, separate display for each remote probe. Best of all it is wireless so you can see it from anywhere!

You'll also need to compile your own source code, and have an FTDI cable to program the ATmega which you had to purchase with a bootloader. Even best case scenario, you're going to have to set the configuration of the remote node with arcane serial commands. A major leap backwards in terms of usability and convenience. Who wants to take their whole device apart and get a cable to hook it to their laptop so they can tweak the configuration?

Cost-wise you subtract the rPi ($30 street), wifi ($10), SD card ($2-10). Fifty bucks. Now add in 2 RF modules ($12+shipping), another PCB ($10+shipping), parts needed to build the remote device (cannibalizing parts from the HeaterMeter) ($10-20), another power adapter ($8), another case ($4-10?)... over fifty bucks.

Same cost, less reliable, more complex, not as easy to use. Is the benefit the fact that is has a physical button on the front?
 
I really like the look of that remote board, if not for the shortcomings brought up by Bryan I would say this looks like the way forward as well. I am on the same page with Tom, ideally I would like to have a weather-proofed unit permanently mounted out at my grill that handles the temp sensing and blower/servo control, and have the HM box just acting as the brain. (and have the brain wireless running on a rechargeable battery :confused:, I know Bryan poo-poo's this idea every time I mention it but....)

So I guess the RF module is a solution that can get this done, but a weak solution as detailed by Bryan. The weak signal from the RF (and thus the possibility to lose connection with the controller) seems to be the main issue (and lack of ability to transmit/modify configuration). That's why I keep coming back around to wanting a WIFI connection on the remote board, it seems if the HM controller and the remote board could communicate over WIFI rather than RF wireless the range and programming issues would be eliminated? Then again, once you put the hardware to connect to WIFI on the remote board you've pretty much got the same sensitive hardware out at the grill as you do in the HM box. And even if you have WIFI out at the remote board the whole thing would need to be re-coded to communicate over it....

...but there has got to be a way to get this done if we just keep bouncing ideas off the wall......
 
I've been enamored with the idea of a remote device. If I use just a servo I could power it all off a battery attached to my smoker. No wires to trip over etc. Now I'm seeing Bryan's point. Changing config manually is not nice. How many people have changed the config on there HM? Probably everyone.

If you want a device in a water proof container to permanently attach to your smoker with WiFi, you have it already. Its a HM. If you don't want the LCD remove the LCD and put it in a case without the hole. I don't see how a daughter card or a HM is any different from each other.

If you then want to control several different devices at once, it would be a matter of writing the client web software to be able to move through different smokers from a single interface. This could work on a web browser, and could probably work on PitDroid as well.

You still need a wifi dongle, probes, cases (water proof or not) per device. Not sure how much you are saving by not just putting in a model a rpi, dropping the lcd and moving forward.

I guess my question to Bryan would be how much effort would it entail to monitor multiple pits from a unified web interface?

dave

For me my smoker weighs a ton. I can easily attach a drawer for the HM that is water proof, looks good for a lot less than trying to waterproof a case for the HM. I can even add a 12V lead acid battery to the thing and not notice much difference in weight. It does have casters to move it around. If I were to do this, I could have no cords attached to my smoker, it would be self contained.
 
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But you're still stuck with having the heatermeter physically tied to the pit.

Oustide.

That's what I'm trying to get away from.

Maybe I didn't articulate what I meant. What I'm saying is that the current lmremote setup is the best low-cost solution for wireless. But you can populate each HM4 PCB with only the components that you need for a dedicated wireless setup. So that means all the temp hardware/blower/servo hardware goes on the wireless board which doesn't need a lot of the ancillary hardware (shift register, button, LCD, pot, buzzer, transistor, resistors, PI header). Same goes for the head/Rpi (10K resistors, probe jacks, RCA, mosfet, cap, diode, resistor).

As far as cost goes, I'm struggling to see any huge difference. Extra PCB + 2x RFM12b + 328p +resonator+reset button+resistors, extra LED, extra power jack, 3x 100uF caps, OKI, MCP. Maybe $30? All that stuff ships from digikey for about $3. And the RFM12b's can be gotten cheaply from ebay for very low shipping as well. OSHpark ships cheaply too. So ~$10 for shipping.

How is what I'm talking about any different from this:

mLTQhGE.png


All I'm saying is that now that all this stuff is on this board you don't need to duplicate it on the HM4/Rpi. This is exactly what Tom suggested and you agreed with earlier in the thread.

I'm just trying to agree! :D
 
D Peart said:
.....I've been enamored with the idea of a remote device...........

....If you want a device in a water proof container to permanently attach to your smoker with WiFi, you have it already. Its a HM.......

....I guess my question to Bryan would be how much effort would it entail to monitor multiple pits from a unified web interface?....

dave
Click to expand...

Same here Dave, but no matter how I slice it when you get enough hardware out at the grill to occomplish that goal you pretty much have a HM out there.... (like you said)

Bryan has commented in the past about the coding for multiple pits, didn't seem overly enthusiastic about it, or how it would even work. I think a tab'd system with a tab for each pit would be the (easiest) way to go. Perhaps with a main frames page that displays the pit and food temps for all pits in a smaller frame, and then the main frame shows the graphs for whichever pit you have selected. (not considering at all HOW the make the HM do this)
 
But you're still stuck with having the lmremote physically tied to the pit.

Outside. . . . sorry had to do that :)

Whats the difference between the LM remote and the HM? Not much, an LCD screen and a rpi?

In the end you still have to provide a waterproof place to put it, still have to power it, still have to have probes, etc. All new software to support it.

Yes as I said I've been enamored with this idea for a long time, but after reading Bryan's post I guess he converted me. I just don't see much difference between an LM remote and a HM. Yes you don't need a rPi and LCD, but what you get with those two additions is a much better user experience and not software changes.

dave

M Miller said:
But you're still stuck with having the heatermeter physically tied to the pit.

Oustide.

That's what I'm trying to get away from.

Maybe I didn't articulate what I meant. What I'm saying is that the current lmremote setup is the best low-cost solution for wireless. But you can populate each HM4 PCB with only the components that you need for a dedicated wireless setup. So that means all the temp hardware/blower/servo hardware goes on the wireless board which doesn't need a lot of the ancillary hardware (shift register, button, LCD, pot, buzzer, transistor, resistors, PI header). Same goes for the head/Rpi (10K resistors, probe jacks, RCA, mosfet, cap, diode, resistor).

As far as cost goes, I'm struggling to see any huge difference. Extra PCB + 2x RFM12b + 328p +resonator+reset button+resistors, extra LED, extra power jack, 3x 100uF caps, OKI, MCP. Maybe $30? All that stuff ships from digikey for about $3. And the RFM12b's can be gotten cheaply from ebay for very low shipping as well. OSHpark ships cheaply too. So ~$10 for shipping.

How is what I'm talking about any different from this:

mLTQhGE.png


All I'm saying is that now that all this stuff is on this board you don't need to duplicate it on the HM4/Rpi. This is exactly what Tom suggested and you agreed with earlier in the thread.

I'm just trying to agree! :D
Click to expand...
 
D Peart said:
But you're still stuck with having the lmremote physically tied to the pit.

Outside. . . . sorry had to do that :)

Whats the difference between the LM remote and the HM? Not much, an LCD screen and a rpi?

dave
Click to expand...

Well, I agree to a point....

The difference is exactly what you state, a HM without a display and rPi, but I think you understate that difference. The HM itself is a pretty robust board, the display and the rPi are the most sensitive parts in the unit. The rPi has an SD Card in it and the LCD can get hot, and moisture is going to play hell on them both. I think the hardware on the LM remote board (root hardware of the HM) is much more capable of surviving outside than the rPi and the display. Not sure about the RF remote hardware, I've never used (or even seen) it. I guess I need to order a couple units and check it out...

Are there any special details about what RF module I should order? (I'm pretty sure the source on the BOM is out of stock, at least it was when I ordered parts to build my first HM)
 
I'd rather have a $25 lmremote board sitting outside than a $70 HM4.

Sacrificial anode.

I guess it comes down to how risk averse you are. I'd rather spend the extra money to keep my high cost components safe. If that means I have to sacrifice a lmremote board every now and then so be it.
 
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RalphTrimble said:
Are there any special details about what RF module I should order? (I'm pretty sure the source on the BOM is out of stock, at least it was when I ordered parts to build my first HM)
Click to expand...
It must be a RFM12B 915MHz. You can get 433MHz or 868MHz (or whatever the European standard is) but you'll also need to recompile heatermeter because it is fixed at 915. You want the surface mount variety not the kind with pins and not one on any sort of breakout board.

Multiple Pits On The Website:
Where is the data coming for this? You can only have one HeaterMeter per Pi because there's just one serial port. If you take that off and rewrite all the code so it runs on the Pi + RFM12B, you can still only receive/transmit on one channel at a time so you can't have one Pi running multiple pits over RF unless you redo the RF protocol too to allow more data. Where is the source of the data?

I've voiced my concerns about the RF system so that's all I'll say about it. Maybe I'm wrong and it will work really well. I guess we'll just have to see what happens!
 
I was thinking that if I just used a HM for each pit it would be nice to have a single website to collate all the pits. I can see how this wouldn't work as it is written today because each website is the server. So I guess I'd just use a different tab in my browser per pit.

dave

Bryan Mayland said:
Multiple Pits On The Website:
Where is the data coming for this? You can only have one HeaterMeter per Pi because there's just one serial port. If you take that off and rewrite all the code so it runs on the Pi + RFM12B, you can still only receive/transmit on one channel at a time so you can't have one Pi running multiple pits over RF unless you redo the RF protocol too to allow more data. Where is the source of the data?
Click to expand...
 
OK, so if I get two RFM12B 915MHz units am I correct in assuming I could run one complete HM with a rPi (plus RF module), and another bare bones HM at the grill with just the basic hardware and RF module (no display or rPi), and I could get probe data and control the HM fan/servo at the grill through the RF module? Or would I need the daughter board you posted last night at the grill instead? I happen to have a spare HM board and parts here already and would be willing to sacrifice it to the elements to experiment with the remote concept...
 
mmmm I didn't consider that sort of build. The probes are wired backwards (Analog 0 through Analog 3 instead of Analog 5 through Analog 2) so you'll only get the overlapping channels, 2 and 3. The LEDs won't work because they're attached to other pins (the have a different purpose on the LMRemote, which is to indicate the status of the "lock" with the transmitter). Also the servo code isn't in lmremote yet... or not the blower either in github, it just receives and leaves it up to the user to decide what to output.

You could get it to work if you make the code changes though!
 
Bryan Mayland said:
mmmm I didn't consider that sort of build. The probes are wired backwards (Analog 0 through Analog 3 instead of Analog 5 through Analog 2) so you'll only get the overlapping channels, 2 and 3. The LEDs won't work because they're attached to other pins (the have a different purpose on the LMRemote, which is to indicate the status of the "lock" with the transmitter). Also the servo code isn't in lmremote yet... or not the blower either in github, it just receives and leaves it up to the user to decide what to output.

You could get it to work if you make the code changes though!
Click to expand...

OK, so it seems I wont really be able to get it done with the two HM boards, at least right now...
Perhaps you could consider that sort of arrangement, where for RF remote you just use two HM boards and kinda split the hardware between them and use one for the remote module, the other for the main unit with the rPi.... Seems logical to me... (the guy that doesn't have to code it! LOL)

If I were to make any efforts in this direction (RF Wireless) I would need it to support both the fan and servo though, cause I like them working together and don't want to sacrifice it....
 
Dave Casazza said:
Wow I really stirred the pot with this thread. Have we gone full circle with the original premise?
Click to expand...

For me it's an "any way to get it done" approach to getting a weather proof wireless module that can stay out by the grill and be controlled by the HM... (running both servo and fan).
 
Ralph: I agree, at least with the analog probe configuration. The reason it is the way it is now is that the original prototype boards only had analog 0 - 3 brought out. I think there are a grand total of 2 people using this setup, but I think it should be swapped. I'll just eat these next prototypes cost with my amazon millions and get it right on the second try. At least I can test the concepts. The LEDs won't ever work right because of the missing shift register that drives two of them. I can move the "locked" LED to use the same as the HeaterMeter RF LED so one could at least see if you're 100% RF locked on (the other two are "searching" and "converging", you should be in locked status >90% of the time). The servo and complete fan is coming, this is all new stuff so I'm in the process of getting the code ready to support it in a way I can feel good about.

Dave: I can't remember, what was the original premise? :-D I think we sort of are. The functionality is similar except wireless. There will only be 1 pit still though, due to the 1 controller = 1 pit limitation.

I protest a lot but I sort of want to be proved wrong on this, which is why I'm willing to devote time to it. If I can put 10-20 hours into it and it turns out great then maybe I was just dragged kicking and screaming into an amazing new way to do things. As I always say "HeaterMeter: Stealing your ideas and making it seem like it was my idea since 2009".

The working servo prototype I need to give Dave Peart props for still. I would have never done it on my own but he sent me one and now look where we are. Follow that up with Ralph's ingenious ping pong damper, Tom and Matt's 3D printed case, I think this year has had the biggest moves forward yet. I'm so proud of you guys (gets choked up)
 
I have a buddy with a family cottage up north and we're looking at using the HeaterMeter as an environmental monitoring system. I could see the wireless probes coming in handy for this!
 
I've put lmremote nodes in my fridge to see how evenly the temperature is distributed. I've got one in my fermenter that's attached to the controller that runs the cooling, and I've got an ITPlus transmitter in my beer fridge monitoring the temp and humidity there. I use them all the time for things outside this project so I'm happy the ability is there for sure!


Orange=Beer, Lime=Fermenter, Green=Outdoor, Gray=Thermistor
 
I must admit the servo prototype was completely selfish on my part. I knew that if it was sitting there on your desk, staring at you daily, you would have to figure out how to get it working :)

dave
 
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