LinkMeter v2 Homebrew BBQ Controller - Part 1


 
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Originally posted by M Rochford:
When putting in the resistance of your resistors are you just saying 10k or you putting in a avg of the all the resistors?
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Each probe can have its own resistance so for the most accurate readings you can measure each resistor R18, R17, R16, and R5 (yes R5 not R15) and enter those using /set?pcX... You can measure them even once they are installed into your HM board, as long as you don't have a probe connected at the time.
 
Originally posted by Bryan Mayland:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Jay Bremner:
1) I remember seeing a thread on here showing the different version of Linksys WRT54G routers (for using in this application) and now, through all my searches, I cannot find it. I picked up a Version 6 yesterday with High-Gain antennas and am wondering if there is anything different I need to do or just follow the Wiki?
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It it is a version 6, the Wikipedia page for WRT54G says that it only has 2MB of flash and 8MB of RAM. The standard LinkMeter image is 3.2MB so you'll have to build your own, stripping out as much as possible. I know someone has done it, but I don't know what the final config was. Also 8MB of RAM is pretty tight, considering we run out even with 16MB if you serve more than 2 HTTP connections at once. If you're going to squeeze it in, you've got your work cut out for you
</div></BLOCKQUOTE>

With a lot of patience, trial and error, and guidance from Bryan, I was able to strip the Firmware down to 1.8M, but it was for a device with USB ports, and thus it boots with to root file system on a USB drive. As for the RAM, my target unit only has 8meg, and I have never had a stability problem. I usually have the HeaterMeter page open in two browsers; Chrome on my win7 box, and the browser on my Smartphone.

I've have not been keeping close tabs on current development, so i don't know what all has changed, but I use this wonderful code on completely different hardware, and it runs like a champ. Nothing like taking a nap while that over night brisket is on.

I basically made a custom power switching board for the blower, a simple resistor array for the temp probes, and a a power regulator for to use homebrew POE. ten slapped an Arduino Mega on a USB print server, loaded a stripped version of the LinkMeter, and cooked some of the finest `que my backyard has ever seen..

I'de be happy to go into more detail or link pics, but It's moving day at the office, and one of my team called in so I have to go pack his work bench.....
 
Thanks for the information, Brian! I appreciate the extra information, and had forgotten that you had your root on USB.

I've pushed up a new LinkMeter OpenWrt snapshot to my web site. This includes:
-- SHADOWPASSWORDS fix that allows you to set your password through the web interface
-- Adds explicit cache control for static HTTP items which really speeds up page loads in the Chrome browser
-- Fixes the ordering of the Network / LinkMeter tabs so they no longer flip back and forth

I've also pushed changes up to GitHub for HeaterMeter Arudino 1.0 support. HeaterMeter will not compile under 0022 any longer. I'll be updating the wiki shortly with this information. Also note that the eagle directory in git will be seeing some changes. Do not use this as reference to build a board! The official PCB schematic and stuff is now linked from the HeaterMeter Hardware wiki page.

I still plan on switching LinkMeter to be based on OpenWrt 10.03.01 once I get a chance but there seems to be a lot of testing and conversion so it may take a while.
 
Originally posted by Brian Hilgert:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Bryan Mayland:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Jay Bremner:
1) I remember seeing a thread on here showing the different version of Linksys WRT54G routers (for using in this application) and now, through all my searches, I cannot find it. I picked up a Version 6 yesterday with High-Gain antennas and am wondering if there is anything different I need to do or just follow the Wiki?
Click to expand...
It it is a version 6, the Wikipedia page for WRT54G says that it only has 2MB of flash and 8MB of RAM. The standard LinkMeter image is 3.2MB so you'll have to build your own, stripping out as much as possible. I know someone has done it, but I don't know what the final config was. Also 8MB of RAM is pretty tight, considering we run out even with 16MB if you serve more than 2 HTTP connections at once. If you're going to squeeze it in, you've got your work cut out for you
</div></BLOCKQUOTE>

With a lot of patience, trial and error, and guidance from Bryan, I was able to strip the Firmware down to 1.8M, but it was for a device with USB ports, and thus it boots with to root file system on a USB drive. As for the RAM, my target unit only has 8meg, and I have never had a stability problem. I usually have the HeaterMeter page open in two browsers; Chrome on my win7 box, and the browser on my Smartphone.

I've have not been keeping close tabs on current development, so i don't know what all has changed, but I use this wonderful code on completely different hardware, and it runs like a champ. Nothing like taking a nap while that over night brisket is on.

I basically made a custom power switching board for the blower, a simple resistor array for the temp probes, and a a power regulator for to use homebrew POE. ten slapped an Arduino Mega on a USB print server, loaded a stripped version of the LinkMeter, and cooked some of the finest `que my backyard has ever seen..

I'de be happy to go into more detail or link pics, but It's moving day at the office, and one of my team called in so I have to go pack his work bench..... </div></BLOCKQUOTE>

Just scored a version 1.0 WRT54G on Ebay for $12.50....Woo Hoo!!
 
Originally posted by Bryan Mayland:
I've pushed up a new LinkMeter OpenWrt snapshot to my web site. This includes:
-- SHADOWPASSWORDS fix that allows you to set your password through the web interface
-- Adds explicit cache control for static HTTP items which really speeds up page loads in the Chrome browser
-- Fixes the ordering of the Network / LinkMeter tabs so they no longer flip back and forth
Click to expand...

Bryan, is this image able to be upgraded to via the web interface? I'm new to OpenWRT (more of a DD-wrt guy previously), but my existing Linkmeter firmware'd WRT won't let me flash this via the web interface (I assume because it's not a "sysupgrade" module). I tried using mtd via the command line, but no dice on that either.

In other news, I assembled my 3.1 HM board this weekend, haven't had time to wire up the LCD or get a serial header on my router yet so it's still a paperweight. Still waiting for my switches to come off backorder too.

http://dl.dropbox.com/u/119708...4%2057%2025%20PM.jpg
 
Originally posted by Kyle Christensen:
Bryan, is this image able to be upgraded to via the web interface? I'm new to OpenWRT (more of a DD-wrt guy previously), but my existing Linkmeter firmware'd WRT won't let me flash this via the web interface (I assume because it's not a "sysupgrade" module). I tried using mtd via the command line, but no dice on that either.
Click to expand...
I've personally never had any success with using the web interface to flash. It hasn't ever worked for me. I just use that page to make a backup (.tar.gz) then telnet/ssh into the router and
sysupgrade http://capnbry.net/linkmeter/s...rcm47xx-squashfs.trx
75% of the time it doesn't come back up so I end up having to flash with the .bin image over TFTP and restoring the backup. I've never hooked up a serial cable to it to see what happens but I'm pretty sure that wouldn't give me a clue either. I prefer DD-WRT myself as far as upgrading goes, it usually works pretty well.

A green PCB? Where did you get that!
 
Originally posted by Bryan Mayland:

I've personally never had any success with using the web interface to flash. It hasn't ever worked for me. I just use that page to make a backup (.tar.gz) then telnet/ssh into the router and
sysupgrade http://capnbry.net/linkmeter/s...rcm47xx-squashfs.trx
75% of the time it doesn't come back up so I end up having to flash with the .bin image over TFTP and restoring the backup. I've never hooked up a serial cable to it to see what happens but I'm pretty sure that wouldn't give me a clue either. I prefer DD-WRT myself as far as upgrading goes, it usually works pretty well.

A green PCB? Where did you get that!
Click to expand...

Haha, 75% failure rate? I don't like the sound of that, having to tftp flash is a pita! That board is the one I got off Duston, I believe it is from batchpcb.com.

I'm a little annoyed that Mouser is backordered on the 4 way through mid Feb. Does anyone have any online sources for the ALPS switch that does small orders and doesn't have silly $20 handling fees?
 
Originally posted by Kyle Christensen:
Haha, 75% failure rate? I don't like the sound of that, having to tftp flash is a pita! That board is the one I got off Duston, I believe it is from batchpcb.com.

I'm a little annoyed that Mouser is backordered on the 4 way through mid Feb. Does anyone have any online sources for the ALPS switch that does small orders and doesn't have silly $20 handling fees?
Click to expand...
I know, right? I wish the sysupgrade would work properly but I have no idea why it does not. Probably something like "Kernel panic can't mount root filesystem" or something.

You can use the surface-mount equivalent part and just glue it to your board with a drop of crazy glue. The little leads on the side are the same width as the through hole part so there's "plenty" to solder to. I can't find any other part that is similar aside from ALPS's own center push version as well. Some things you think "Golly, there's got to be a ton of people who make these" and then you can't find one. I mean aren't directional switches on like everything these days?
 
Originally posted by Bryan Mayland:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Kyle Christensen:
Haha, 75% failure rate? I don't like the sound of that, having to tftp flash is a pita! That board is the one I got off Duston, I believe it is from batchpcb.com.

I'm a little annoyed that Mouser is backordered on the 4 way through mid Feb. Does anyone have any online sources for the ALPS switch that does small orders and doesn't have silly $20 handling fees?
Click to expand...
I know, right? I wish the sysupgrade would work properly but I have no idea why it does not. Probably something like "Kernel panic can't mount root filesystem" or something.

You can use the surface-mount equivalent part and just glue it to your board with a drop of crazy glue. The little leads on the side are the same width as the through hole part so there's "plenty" to solder to. I can't find any other part that is similar aside from ALPS's own center push version as well. Some things you think "Golly, there's got to be a ton of people who make these" and then you can't find one. I mean aren't directional switches on like everything these days? </div></BLOCKQUOTE>


Hmm. I sysupdated and it appeared to take (it rebooted and didn't brick my router anyway), but I'm not exactly sure how to verify (which build # to look at, if any).
 
Originally posted by Kyle Christensen:
Hmm. I sysupdated and it appeared to take (it rebooted and didn't brick my router anyway), but I'm not exactly sure how to verify (which build # to look at, if any).
Click to expand...
Congrats! If you look at the top of any page other than the LinkMeter Home screen, you should see "OpenWrt | Attitude Adjustment (r29664)" the r29664 is the Wrt build, which is what yours should be now.
 
Originally posted by Bryan Mayland:
Congrats! If you look at the top of any page other than the LinkMeter Home screen, you should see "OpenWrt | Attitude Adjustment (r29664)" the r29664 is the Wrt build, which is what yours should be now.
Click to expand...

Affirmative! That's what I figured the build number was. On my WRT54GS in the OpenWRT portion of the firmware, the form rendering seems abysmally slow, is it normally that way?
 
Originally posted by Kyle Christensen:
Affirmative! That's what I figured the build number was. On my WRT54GS in the OpenWRT portion of the firmware, the form rendering seems abysmally slow, is it normally that way?
Click to expand...
Oh god yes it is the worst. A normal page can take 5-7s to load. If the router is doing something else at the same time, it can take a minute, or it can even run out of memory and reboot!
 
Originally posted by D Peart:
Bryan, I'm interested in your V4.0 board. My next project is to convert one of the temp probes to a humidity sensor. I then want to use that to control a SSR to turn on/off a humidifier. My goal is to control both temp and humidity for making salami. If you are freeing up an output that should allow me to do this.
Click to expand...
Took a little longer than I thought but this is in github now, with the commit labeled "V3.2 draft with 74HC595 shift register" and the date in the EAGLE frame is 1/10/12 11:07:23AM. The board file should be ready to CAM if you're going to make one. I still haven't tested it with the RFM12 board running simultaneously but it should work hardware-wise. They should also work software-wise except in the case where the RFM12 is transmitting/receiving and the LCD wants to change, where either the LCD can get messed up or the RFM12 could corrupt the transmission (due to high interrupt latency).

EDIT: The digital pin that is freed is PIN_LCD_DATA (8).
 
Originally posted by Bryan Mayland:
Took a little longer than I thought but this is in github now, with the commit labeled "V3.2 draft with 74HC595 shift register" and the date in the EAGLE frame is 1/10/12 11:07:23AM. The board file should be ready to CAM if you're going to make one. I still haven't tested it with the RFM12 board running simultaneously but it should work hardware-wise. They should also work software-wise except in the case where the RFM12 is transmitting/receiving and the LCD wants to change, where either the LCD can get messed up or the RFM12 could corrupt the transmission (due to high interrupt latency).

EDIT: The digital pin that is freed is PIN_LCD_DATA (8).
Click to expand...

Why did you go with the 74HC595 shift register?
 
Originally posted by M Rochford:
Why did you go with the 74HC595 shift register?
Click to expand...
Over the existing design? It is latched so it gets around the hokey AND gate made by the resistor/diode combination on the current board. I actually bought some SPI to parallel out converters with the idea of effectively making an SPI LCD when it occurred to me a shift register would work effectively the same except costs less and is more readily available. The SPI transfer is also a lot (5x) faster, not that it matters.
 
Originally posted by Jon Schelmbauer:
I think I answered my own question...my first search for an HC returned zero results, but this time I got
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Yeah I actually got 10 for $3 shipped USPS from somewhere else. They're relatively cheap parts.
 
Thanks, I'll take a look.

Have you thought about using 1/8 watt resistors instead of the 1/4 watt ones? They quite a bit smaller and would give you some board space back. All the 10k pull up resistors could easily be 1/8 rated.

just a thought,
dave

Originally posted by Bryan Mayland:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by D Peart:
Bryan, I'm interested in your V4.0 board. My next project is to convert one of the temp probes to a humidity sensor. I then want to use that to control a SSR to turn on/off a humidifier. My goal is to control both temp and humidity for making salami. If you are freeing up an output that should allow me to do this.
Click to expand...
Took a little longer than I thought but this is in github now, with the commit labeled "V3.2 draft with 74HC595 shift register" and the date in the EAGLE frame is 1/10/12 11:07:23AM. The board file should be ready to CAM if you're going to make one. I still haven't tested it with the RFM12 board running simultaneously but it should work hardware-wise. They should also work software-wise except in the case where the RFM12 is transmitting/receiving and the LCD wants to change, where either the LCD can get messed up or the RFM12 could corrupt the transmission (due to high interrupt latency).

EDIT: The digital pin that is freed is PIN_LCD_DATA (8). </div></BLOCKQUOTE>
 
I agree that it would be fantastic if the controller started using Raspberry Pi. If it lives up to the hype it seems like it will be a very nice platform to do development on.
 
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