HeaterMeter v4.0 for RaspberyPi / Standalone

Bryan Mayland

TVWBB Honor Circle
Continuing on the success of the LinkMeter Project come the HeaterMeter v4.0 revision for RasbperryPi or standalone use.

HeaterMeter for RaspberryPi joins an Arduino / AVR ATmega328 microcontroller with OpenWrt running on a RaspberryPi $35 wonder-computer for the purpose of providing oven-like control of a charcoal BBQ grill via web interface. The microcontroller controls a fan which limits airflow to the pit, displays the current status on a character LCD, and passes the data on to the RaspberyPi which streams real-time updates to connected web browsers. The website also works on mobile browsers running Android or iOS, allowing users to unchain themselves from their grills and partake in many life-enriching activities such as
  • Going to the grocery store to buy more beer
  • Going to a bar to drink more beer
  • Not get off the couch, where your beer is
  • Possibly other non-beer related hobbies
HeaterMeter is also reportedly suitable for connecting to a solid state relay and controlling a sous vide heater if you prefer your food float around in fancy water instead of smoke and fire.

LinkMeter Home Screen


Project Page - GitHub Hosting
LinkMeter/HeaterMeter is an 100% open source project and is hosted on my GitHub page. The ultimate source for information is the HeaterMeter Project Wiki and the TVWBB SubForum. Open source means you're free to modify it as you see fit. Change the background color to cyan, replace everywhere it says "Pit" with the word "Poo", rewrite the whole thing in Visual Basic or just add a feature I'm too dumb or busy to implement.

Hardware
Pin compatible with the v3.0 units, HeaterMeter v4.0 changes form factor to better integrate with the RaspberryPi. All jacks and buttons are now contained on the board itself, requiring no external button boards or wiring. Schematics are in git, but please use the v4.0 snapshots as git may be experimental depending on when you see it. Parts lists and build instructions are in the wiki. The wireless adapter of choice is an Realtek 8192cu-based USB wifi adapter. The Edimax EW-7811Un or Airlink AWLL5099 work better than their $10 price tag would imply.


Software
The temporary home for the OpenWrt image, which includes the HeaterMeter AVR firmware is on my website. Unzip the img from the openwrt-rpi.zip file and write it to an SD card (32MB or larger) using Win32DiskImager. Insert it and off you go.

I already have a LinkMeter WRT54GL is this better?
Well life wouldn't be worth living if everything didn't always get better would it? Take your bulky old Linksys router and throw it directly into the garbage. HeaterMeter v4.0 improves on this design
  • Small! 3.2" x 4.2" x 1.0" overall
  • Piezo buzzer alarm goes beep-beep-beep, deafening unsuspecting B(BQ)urglers
  • 3 LEDs with upcoming customization functions in both on and off varieties
  • Much faster web interface, up to 10x in vague subjective analysis
  • Built-in storage without soldering teeny wires and wrecking your junk
  • No more ISCP/USBTinyISP/Optiboot bootloader loading operation, blank chip is automatically flashed on first boot
  • No TFTP flashing, just write the image to an SD card and go
  • Reliable serial operation make you feel like you're US Robotics and it is 1997 forever

Sounds great, but is it pretty?
3D printed cases are all the rage, and you can have one printed by any friend with an extrusion printer in probably around $25 in materials. Helpful forum members can also print one for you.


The FUTURE
I have been putting in 30+ hours a week for months on this project, with development starting nearly 3 years ago now. There are tons of new features to add (see the TODO list in the wiki) and new ideas keep coming from new users.

HeaterMeter 4.0 PCBs
I order them from OSH Park, where they come in quantity 3. You're free to order your own set, and sell your extras here. OSH Park also now has them available in singles in their store.
 
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Dennis C

TVWBB Fan
looks like a nice design on the case. I cannot wait to start this project, even though I only used the Linksys one three times. :)

Is that the same LCD as the Linksys version? I still have that LCD on hand from the other project as I didn't use it.


I was following the other topic closely, but people here may have not. Does Class of the SD card make any difference? Brand?
 
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Dave Casazza

TVWBB Fan
Hi Bryan,

Can you post your eagle libraries with v4 sch and brd files? I'd like to use a power adapter for the blower output, rather than RCA for a more robust connection.

Thanks,

Dave
 

Bryan Mayland

TVWBB Honor Circle
Is that the same LCD as the Linksys version? I still have that LCD on hand from the other project as I didn't use it.

I was following the other topic closely, but people here may have not. Does Class of the SD card make any difference? Brand?
Yeah the LCD is the same, as are most of the other parts. The LCD is the one component I try to use as much as possible when building these things, on account of them being the most expensive part.

The SD card speed shouldn't matter. We're still on OpenWrt so that's designed to run on much slower flash devices. I'd stick with verified working Raspbery Pi SD cards, although the compatibility is pretty good so if you have an old card you were planning to use, try it before you purchase one. If you have a monitor plugged in, there should be no repeating errors about "still waiting for final write" or "status error -110".

Dave, you should be able to just copy paste any part I have on the schematic to get a new instance of it. I'll post my library tomorrow though.
 

D Peart

TVWBB Pro
Dave,
If you modify the blower output connector to a standard DC power connector, I'll buy the other two boards if you don't want them :)

I prefer the DC power connectors as well, I always feel like I'm going to short something out with an RCA connection.

dave

Hi Bryan,

Can you post your eagle libraries with v4 sch and brd files? I'd like to use a power adapter for the blower output, rather than RCA for a more robust connection.

Thanks,

Dave
 

Dennis C

TVWBB Fan
Ordered all my parts. Digi-key had two and Mouser had one part that was not in stock and backordered. Looks like I'm waiting a month to get the parts, unless they get it in sooner.


Digi-Key -
S7116-ND CONN HEADER FMAL 26PS.1" DL GOLD Estimated Ship Date 9/26/2012
811-2692-ND 24VIN 5VOUT 1.5AMP SIP HORIZONT Estimated Ship Date 9/27/2012 (Available from Mouser now.)


Mouser -
163-7620E-E DC Power Connectors PCB 2.1MM Estimated Ship Date 10/4/2012

Gives me time to order the case once Bryan's is done.
 

Dennis C

TVWBB Fan
Ordered already so no biggie. I don't mind waiting on the parts. I have the Linksys that I can play around with for the time being.
 

Dennis C

TVWBB Fan
Don't know if it is too late Bryan, but Ponoko is offering 20% off laser cutting until 9/10/2012

Anxious to see how your case turns out. Ready to buy one myself :)
 

Bryan Mayland

TVWBB Honor Circle
Yup! I got the 20% off on my prototype. I think it was $36 or so before the discount, so it saved a (relatively) considerable amount of money. The shipping was still $11 so that's the real killer there. I'm hoping when it is finalized and I do 2x P1 pieces instead of 1x P2 that the shipping will be cheaper because they can stuff it in a regular padded envelope instead of and UPS flatpack.
 

Dennis C

TVWBB Fan
Yup! I got the 20% off on my prototype. I think it was $36 or so before the discount, so it saved a (relatively) considerable amount of money. The shipping was still $11 so that's the real killer there. I'm hoping when it is finalized and I do 2x P1 pieces instead of 1x P2 that the shipping will be cheaper because they can stuff it in a regular padded envelope instead of and UPS flatpack.
Thats great. Every penny saved is good these days. How long did it take to design the case? I'm lucky I could fit two legos together. :)
 

PerryRT

New member
Thats great. Every penny saved is good these days.
Speaking of saving a few pennies...a general question. I've been starting my build with the "B" board that I have, but one of these days, I'd like to turn that into a media center. Since it looks like the "A" board may be available in the reasonably near future (in the next six months, it seems), is there any reason why a Linkmeter build wouldn't work with an "A" board?
 

Bryan Mayland

TVWBB Honor Circle
I agree with the penny saved mantra, the "A" rPi board will be the preferred platform for the HeaterMeter Pi. I can't imagine they'd change the position of the existing connectors so the HeaterMeter board should mate with it implicitly. I too will be repurposing one of my rPi for entertainment purposes once the "A" is released. At some point I'm hoping they'll make a WiFi-included version with no ethernet and that will be one less thing to worry about.

Designing the case took about half a Saturday. This included time to experiment with Ponoko as well as learning the Inkscape software and printing and assembling a cardboard prototype. If you've planning to do it, something that took me a while to figure out was that the Ponoko template has a built-in scaling factor that messes up all the measurements. To get accurate sizing, you have to build the parts in a clean inkscape document, then import them into the P1/P2 templates which will scale them properly for the laser cutter. It is quick and easy to import them, so it isn't a problem, it just means you can't design right in the template.

I've also spent some time writing up the assembly and install procedure which just needs some touchup and the images added from my the HeaterMeter Picasa. Suggestions are encouraged. Still need to build the Digikey and Mouser projects.
 

Dennis C

TVWBB Fan
I agree with the penny saved mantra, the "A" rPi board will be the preferred platform for the HeaterMeter Pi. I can't imagine they'd change the position of the existing connectors so the HeaterMeter board should mate with it implicitly. I too will be repurposing one of my rPi for entertainment purposes once the "A" is released. At some point I'm hoping they'll make a WiFi-included version with no ethernet and that will be one less thing to worry about.

Designing the case took about half a Saturday. This included time to experiment with Ponoko as well as learning the Inkscape software and printing and assembling a cardboard prototype. If you've planning to do it, something that took me a while to figure out was that the Ponoko template has a built-in scaling factor that messes up all the measurements. To get accurate sizing, you have to build the parts in a clean inkscape document, then import them into the P1/P2 templates which will scale them properly for the laser cutter. It is quick and easy to import them, so it isn't a problem, it just means you can't design right in the template.

I've also spent some time writing up the assembly and install procedure which just needs some touchup and the images added from my the HeaterMeter Picasa. Suggestions are encouraged. Still need to build the Digikey and Mouser projects.

Nice job on the guide/walkthrough. Hopefully the parts arrive sooner then later (Mouser and digi-key have a parts out of stock, but arriving early October 2012.) so I can begin. I really cannot even start to design the case until I get one together.
 

Bryan Mayland

TVWBB Honor Circle
Oh I remembered the thing I had forgotten to include in the original parts list, the 28pin DIP socket. It isn't required but if you manage to blow up a chip like I did, getting it desoldered would be a real pain. Also you can use the Pi to flash bootloaders on other chips!
 

Dennis C

TVWBB Fan
Oh I remembered the thing I had forgotten to include in the original parts list, the 28pin DIP socket. It isn't required but if you manage to blow up a chip like I did, getting it desoldered would be a real pain. Also you can use the Pi to flash bootloaders on other chips!
Did you add it to the list? My order didn't ship yet so I should be able to just add it to order
 

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