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HeaterMeter v5.0 Development


 
Bryan Mayland

Bryan Mayland

TVWBB Hall of Fame
A lot of people have been wondering what the future holds for HeaterMeter, given that the RaspberryPi B models we all love are slowing disappearing due to them being discontinued. HeaterMeter v4.x just won't mate properly with a B+. I tipped my hand in another thread so I figured I'd be open about it. I spent many hours trying different layouts and wasn't really happy with the feel of of the new, larger design. It added 0.4" to the design and it really started to feel like a giant pancake.

I also tried a few other host boards. VoCore, GL.iNET, TL-WR703N. These had a cost and size advantage but they were more difficult to set up or would have probably caused more headaches than they were worth.

Last week I made a mockup that I am going to move forward on. The new design goes up instead of out, and measures 3.6"x3.6"x1.6" (final height approximate). The LCD, LEDs and buttons will be on a second board which can be omitted if you don't need display capability. Did you say buttons plural? Yes good catch! Because the 4-way directional switch we use has also been discontinued I have switched over to 4x 6mm square tactile buttons. These are ubiquitous from several vendor and I am happy to go back to the 4 buttons instead of the one directional switch, which sometimes seemed to get the wrong direction pressed.



Disadvantages of 5.0 over 4.x:
-- Thicker (Z-axis), Taller (Y-Axis)
-- Will cost a few dollars more
-- No RF wireless
-- No FTDI connector
-- Does not mate with Raspberry Pi A/B

Advantages of 5.x:
-- Mates with Raspberry Pi B+
-- Uses buttons that aren't end-of-lifed
-- Thinner (X-Axis)
-- RJ-45 breakout holes

There's also a completely separate analog section. I'd like to see if I can get this to work again, to lower the noise from bad power supplies or touching the probes. This may or may not work.

The LCD also should be able to attach without removing the spacers on the pin header. We shall see about that too.

I am hoping to get the LCD board finished this weekend, then the first set of rev 0 boards will be ordered. We're looking at probably two months if everything goes well. Or many more months if it doesn't. Regular release (schematics and documentation) then roughly another month after that for v5.0 kits.

To be clear, this adds nothing functionality-wise and we'll actually lose some. The only reason for its design is to be able to use Raspberry Pi B+.
 
So if we already have 4.2.4 systems, there is no real point to changing to 5.0 when it is available. Will the software be the same for the 4.2.4 as it will be for the 5.0?
Again, thanks for all of your hard work!!
 
Nice.

Since the case is going to be so much taller, any chance for a 4 x TC add-on board?

Something like this:

 
I know mouser carries the 2.5mm inline jack $.68cents each that are much cheaper then the ones being used and have to order from Digikey $1.24 each.

Would you be willing to change to those as they are cheaper and can get from mouser and can save some space. I bought some and they look as good.
 
Hmm, move sideways, maybe even back a bit just to work with the B+... I'm wondering if the HMv4.2 with the (cheaper) A+ might end up more popular? (if not for the button end of life issue) I had suggested the mouser jacks a while ago 'cause of the price, and they have a nice small footprint, and I have been using them on roto dampers for over a year and have found them to be solid. So I think thats would be a good move, a no-brainer... I kinda wish they had made good on keeping the straight rPi B model available into the future, things would be so much easier, 'cause we don't really need anything new the B+ has to offer...
 
-- Having the option to have a second board that had support for 4 thermocouples would have made the board at least 0.2" wider and I didn't want to do that. This may be revisited before 5.0 though depending on if other requirements necessitate. Having the option on a single board that worked both ways doubled the cost and was right out.

-- I didn't use the other jacks because I couldn't fit the TC components inside the jacks and still route in a non-bonkers way. This was one of the first things I was doing though, and I didn't want to get hung up on it so I shelved it because I made a deadline. I said "You MUST create something, anything, even if it is awful by Sunday". I will try again to work them in for the next version.

-- And yes, there is nothing superior on this board versus a v4.x. The software is the same. The functionality is the same. It only mates with a A+/B+ and that is the only feature. If anyone is asking "should I wait?" the answer is no because you get nothing for the wait. Of course, if Pi B's are $60 then things even out on the cost. I'm thinking this design will be over $10 more than the current design so factor that into the cost of a B+ vs a B.
 
Ah yes, here's the other reason we can't use those jacks (in addition to there being no room for TC parts)


We can't do plated slots at the fab so you need a drill the size of the pin. The pin on our existing front jack is smaller and placed further back, a combination that allows the drill to work. If a drill touches or passes the dimension line, the fab won't plate it any more so the drill (and possibly the annular ring) needs to fit inside the dimension. If I take the drill down to 2.2mm (10% smaller than recommended footprint) it just barely makes it.

The probe jack interface header would also have to be removed for obvious reasons.
 
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so the ver 5 will have an option for lcd with the use of an additional board?

I never use the 4 way directional, or the lcd, i just plug mine in an go inside and control it via wifi.
 
JHalasz said:
so the ver 5 will have an option for lcd with the use of an additional board?
I never use the 4 way directional, or the lcd, i just plug mine in an go inside and control it via wifi.
Click to expand...
Yup! LCD board contains nothing vital to operation so you can run without it and get a super slim unit, without the LCD backpack the whole thing is about 5mm thinner than the current heatermeter!

I've modified the PCB to make it 0.1" wider. It isn't necessary and adds 30 cents to everyone's cost, but that means that a main board can be created that supports 4 thermocouples if desired. 4 thermocouples adds $10 to the PCB cost and of course the ~$20 in parts. The LCD/Button/LED board can be shared between the two designs.

I was trying to work out placements now that we're a lot more flexible with the new two board design. I switched from 6mm to 12mm buttons because the 6mm versions were so tiny once you saw them in mockup. The caps come in 12mmx12mm shown here in 6 colors. You can also get 9.5mm round (our current cap). Nudging everything around I think this is about right.


Someone also said in another thread "where's the reset button on this thing?!" so I'm also going to try to work in a configuration button on the PCB. Holding it down while booting can prevent the config restore function, and I may be able to get it to actually wipe the configuration without reflashing (although that's a larger challenge because our filesystem isn't like a router's overlay filesystem). It is going to have to go under the LCD though so you'll have to remove the LCD backpack to access it. Not ideal but there's space there.
 
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I had suggest the hardware reset option in the other thread. Is there no way you could use one of the 4 buttons on the HM for hardware reset? For instance, if you power on the unit while holding the down button the HM boots with no restore?
 
I was just about to say "NO! they are separate" but then I started thinking about it and I think I can make it work like that on existing hardware and I wouldn't have to route the extra button. I actually had something like this in the original HeaterMeter to configure the wifi. I didn't think I could make the HeaterMeter interact with the Pi like that but I just had an idea how I can make it work. Thanks for bringing it up again! You're on a roll lately :)
 
This is now in the snapshot build. Requires an upgrade to the LinkMeter package for openwrt (dated after now) and HeaterMeter AVR firmware update (20150110).

When you do "Reset config?" from the HeaterMeter menus, if the RPi is connected it will reset the device configuration and reboot. Due to there being a bug in OpenWrt, the "root" user password remains through the reset. I'll have to figure out how to get around that, but at least it resets the network config.

Note! You must wait for the link between the HeaterMeter and RPi to establish before resetting the configuration. To do this, just wait at least 30 seconds after plugging the power in. If the link is established you will see "Resetting configuration...." on the LCD display. If nothing happens, there was no link, try again in a few seconds.
 
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Bryan, I had a hard time trying to understand the post you made about the reason for the probe jacks. I have them both together in the follow picture and besides the inline one being a tad longer the only difference is the 3rd leg. the 1st and last legs are exactly the same. And OSH does drill slot holes instead of the round holes used on the Heatermeter.

2vxqd8o.jpg
 
It's really a disappointment that flashing the VoCore isn't a streamlined process. I guess we'll have to wait for 6.0 to get VoCore coupled with two or three thermocouples.

Maybe I'm biased because that's my dream HeaterMeter, but I digress.
 
John Bostwick said:
Bryan, I had a hard time trying to understand the post you made about the reason for the probe jacks. I have them both together in the follow picture and besides the inline one being a tad longer the only difference is the 3rd leg. the 1st and last legs are exactly the same. And OSH does drill slot holes instead of the round holes used on the Heatermeter.
Click to expand...
I was going strictly by the datasheet and what Laen has told me about the boardhouse. The datasheet says the front pin (the one closest to the jack) is 2.0mm wide, versus 1.6mm wide. Can you fit that front pin in our existing front hole (which is 1.8mm - plating)?

Regarding the plated slots, I specifically asked Laen about them for the existing jacks (which I built a milled slot for initially) and he said that "The boardhouse has been doing them fairly regularly but they're not supposed to be included in the service we request". Fairly regularly isn't that great if I order 3 and it comes out fine, then order $1000 worth and they come back with no holes at all. I could ask again if you're getting boards made and they come back with plated slots every time. Do you have an EAGLE part for them?
 
Im getting some boards back today, i will check after work. The last boards i recieved had slot holes for the current jack and would fit the inline jack except for the middle pin of course. Anyway, if the boards are good and plated, I'll send ya the eagle part, later today.
 
Yeah if they do the plated slot that would mean there would be more room and I could probably route the integrated thermocouple more easily too.
 
Yeah I saw that, but the question isn't was it done but rather will they do it every time. As someone who still hasn't received a dime from all the work I've put into Smokin' Hardware Inc., I can't afford to bet $1000 worth of PCBs on "most of the time".
 
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