RESOLVED: HeaterMeter v4.1 or wait for v4.2?


 
Bryan Mayland

Bryan Mayland

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I'm getting a lot of questions about which board is the board to build these days. What's the v4.2? Should I build a v4.1 or get a v4.0 single? When is v4.2 coming out? I have a lovely daughter, will you marry her?

Short answer: wait for v4.2.x.

The HeaterMeter v4.2 board has been in development for many months and through several revisions including a complete redesign. At a couple points I thought for sure I'd never be happy with the performance but after the redesign I'm rather pleased and things started to move quickly. It has a bunch of new features that improve the HeaterMeter hardware experience
  • Reduced probe noise from a better segregation of high power and analog circuitry
  • More stable readings from integrated low pass filtering on board
  • Finer blower control with new TruVolt(tm) switching voltage output (which also is less noisy to the analog circuitry)
  • ~5V servo PWM drive for longer cables with less servo freakouts
  • Smaller overall package
  • Optional thermocouple pit probe support on board

As you've seen around the forum 4.2.3 is already in beta and there were just a few tweaks. Documentation is already starting to appear in the wiki. I'm currently waiting on 4.2.4 boards to build and verify, which should be here in a little over a week. If it works for me, the other boards go out to testers for confirmation. If that's good then we're go for v4.2 launch which comes with new Pi firmware with support for new wifi adapters, custom homepage styles, better noise rejection to keep probes from dropping off at room temperature, and more reliable button detection. The timeline for all of this is about a month from now.

v4.1 users will still get all the software features, but I recommend anyone looking to start a new build wait a month and see where we are.

EDIT: v4.2.x boards will also be available in singles from the OSHPark store.
 
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As tough as it is for me to wait for something, having built a v4.2.3 prototype board I have to say it rocks and is worth waiting for, for all the reasons you listed. You hit the ball out of the park with this one!
 
I purchased the parts shortly after the 4.1.2 board was designed but never got a board. I was waiting for the bugs to be worked out. Are many of the parts good that I have for the 4.1.2 to use on the 4.2 boards, or do I need to order a whole new set?
 
The SMD thermocouple parts are new, but you dont need them if you run all standard probes. The NPN transistors have all been swapped for MOSFETS, so you wont need those NPN.... That said, most of the parts are the same, you will need some extra .1uf caps, a couple different/extra resistors, and the MOSFETs etc... So, yah, you can use most of what you have for the v4.1 board on the new v4.2 board, but will have to get a little extra stuff to complete the build....
 
Cool I want to get the thermocouple probe set up, high temp pizza cooks in my keg are great, will be nice to have the heatermeter helping out.
That is only reason I want to build the new one, and to fun assembling and testing it.
 
The SMD soldering isn't TOO bad, get one of those cheap magnifying visors ($3 at Harbor Freight) and you will be able to see the parts clearly enough to solder. I was really skeptical about getting it done but it actually went super easy....
 
RalphTrimble said:
The SMD soldering isn't TOO bad, get one of those cheap magnifying visors ($3 at Harbor Freight) and you will be able to see the parts clearly enough to solder. I was really skeptical about getting it done but it actually went super easy....
Click to expand...

I will get some practice, next week fixing someone's(from work) Samsung S3 charging port. Desoldering the jack with a heat gun and then soldering a new one on. 11 tiny pads on a usb mini port. That's going to be some fun. I told her, I can get the part for 2 dollars and try to fix it, but if I fail then the phone is ruined or she could pay the 100 and Verizon can fix it or replace. She took the cheapest route, lol.

When using a thermocouple, do you have to enter the coefficients, like the probes? or can I get any thermocouple from Thermoworks and it should work
 
You need a type K thermocouple (they come in a couple different letter designations), in the HM Config there is only a setting for mV/C which is actually the gain setting for the thermocouple amp, not the thermocouple. So as far as I know you should be able to use any type K thermocouple.... I'm pretty sure I am correct in saying that, but Bryan can correct me if I am wrong...
I got a high heat type K thermocouple from ThermoWorks that is waterproof and rated for "semi" permanent installations, but there is no need to buy from them in particular, or any model in particular. I also bought a cheapo thermocouple from Amazon but haven't gotten a chance to test it yet, will report back when I do. They are like thermistor probes in that they are each rated for their particular temperature range (that can vary quite a bit) and have different degrees of durability and resistance to water and steam...
 
That's right, all thermocouples are the same, the only difference is in the braid (temperature resistance) and enclosing of the junction (temperature and moisture resistance). There's also grounding of the junction but HeaterMeter works with both grounded and ungrounded, however they are not interchangeable (ungrounded requires an extra resistor in HM).

Every thermocouple I've used, from the massively cheap bare junctions that come with super-cheap thermocouple thermometers, to the regular-cheap $4-5 thermocouples with the enclosed junctions, to the expensive thermoworks probes all have worked equally well. It really just comes down to how you plan to use it or mount it which physical properties you desire.
 
Bryan Mayland said:
There's also grounding of the junction but HeaterMeter works with both grounded and ungrounded, however they are not interchangeable (ungrounded requires an extra resistor in HM).
Click to expand...

Hmm, maybe I am confused, but Thermoworks said the thermocouple I got was isolated, which I take as ungrounded? It worked fine on my HM.... what/where is the extra resistor, do I have it already?
 
This probably says "newbie" all over it... but is it realistic to disassemble a 4.1.4 down the road and re-use at least some of the parts to make a 4.2.x?

The last piece for my 4.1.4 is arriving tomorrow (the boards), and I've been ready to build since two years ago. :)

Thanks for the continued incredible development!
 
Well, personally I would say if you've waited two years you can wait a couple more weeks? It wouldn't be impossible to disassemble an older HM to use the parts on the new one, but some of the stuff will be pretty hard for you to remove cleanly if you aren't super skilled at soldering and having specialized desoldering tools. The ATMega will come out easy cause of the socket, you can just get a new socket for the new HM, but the shift register and the display in particular will be difficult to remove cleanly... I would advise you to either build what you got and keep it that way, or wait for the v4.2 release, and not attempt to disassemble....
 
RalphTrimble said:
Hmm, maybe I am confused, but Thermoworks said the thermocouple I got was isolated, which I take as ungrounded? It worked fine on my HM.... what/where is the extra resistor, do I have it already?
Click to expand...
Yeah isolated implies ungrounded. You already have the extra resistor, it is that 1k one that is labeled 10k I said might need to be swapped out to change the ground impedance.
 
Andrew Flusche said:
This probably says "newbie" all over it... but is it realistic to disassemble a 4.1.4 down the road and re-use at least some of the parts to make a 4.2.x?
The last piece for my 4.1.4 is arriving tomorrow (the boards), and I've been ready to build since two years ago. :)
Click to expand...
The combined total cost of the HeaterMeter (sans PCB, blower, probes, wall wart, shipping) is $39. You can easily reuse the ATmega ($3), 5V regulator ($4), thermistor ($1), and probe jacks ($8). From there it gets a little more complicated LCD ($10), RJ45 jack ($1), buzzer (<$1)... the rest aren't worth the time to desolder. Maybe you can get the Pi connector out but man that won't be fun.

So you can salvage $16-$28 of the $39 without going crazy with effort. However, I reckon someone would pay you $40 for a used assembled HeaterMeter v4.1.4 for almost no effort at all.
 
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OK, I left that SMD resistor off and used a 1/4 watt tapped in place... I'm trying to remember if I actually put 1k or 10K in there now... At any rate, whatever I've got in there is working well... but it's good to know I might have to remove that if I get a grounded thermocouple. I have an Amazon cheapo here that I will be testing soon, not sure if it is grounded or ungrounded.

So far I am real happy with how the thermocouple has been working, even over the CAT5 cable, with the offset it seems to read steady and true. I am not having any issues with noise what so ever... I see the thermocouple jostle around up and down no more than 0.1 degrees, which is totally acceptable and way less fluctuation than I was seeing on previous builds with thermistor probes. The thermistor probes seem rock solid on this build, I'm not noticing any fluctuation at all with them. I am not sure if the reason the thermocouple is having that very small movement is due to noise, or because it has faster response than the thermistors, or due to the reduced resolution of the thermocouple. At any rate, it's well within the reasonable operational range and a big improvement over what I was seeing on previous builds....
 
Yah, that's a good idea, cause you will gain some experience in the process as well... Only thing is the case will be different, so you will have to either go without the case or sell the 4.1 case along with the 4.1 board....
 
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