LinkMeter v2 Homebrew BBQ Controller - Part 2


 

Bryan Mayland

TVWBB Hall of Fame
Well, I have to get rid of my WSM. My stupid HOA has outlawed charcoal grills/smokers. You melt hole through the stucco flooring of your balcony, and they never forgive you. (To be fair, that was pretty stupid of me. Also they probably don't even know I did that.)
Hahah wow! That's a rough one. What if you build a bracket that extends out over the balcony so that technically the smoker isn't on your property any more? :-D
 

Jackson Raygor

New member
Help, I messed up my linkmeter.
My linkmeter was working fine (I used 4 probes on it to monitor a brisket cook last weekend that turned out great), except I did not have a fan yet. Well the fan showed up today, so I excitedly wired it up and plugged it in. The fan did not start and the LCD instantly turned off. So I immediately unplugged it, and unplugged the fan. Then I plugged the linkmeter back in without the fan and have the following issues:
- LCD isnt blank, its just very very dim (it didnt used to be)
- LED on the hetermeter board briefly flashes twice then stays off (I thought I remembered this stay on permanently from my initial build, but could be wrong)
- web interface seems to still be working fine / temp probes are still reporting correct temps

I opened the case, checked connections, smelled the board and looked for burnt components and cannot find anything. What could mis-wiring the fan possibly have wrecked on the board that would cause the LCD to be so dim?
 

John Bostwick

TVWBB Wizard
Make sure your Cap and Diode are soldered the right direction

Use a meter to check for any shorts wires to and from the fan and on the board, Check solder joints for any bridges

It sounds like you have a short

You might be able to get the britness back by using the "lb-" command
 

D Peart

TVWBB Pro
Well that's not fun.

The green LED only flashes, then turns off, so that is normal.
It sounds like the LCD is working, but the backlight is not as bright as before? Did you check the backlight setting in the LM, just in case it got reset? Look on the configuration page it has a spot for backlight percentage.

As for the fan, just one quick question, you sure you hooked the fan up to the fan jumper and not the button jumper? Just checking here. . .

Did the fan spin at all for the short time it was connected?

Is your fan good? Can you try running it directly from your power supply or check the resistance of it? If the fan is shorted out, this could explain what happened.

dave


Help, I messed up my linkmeter.
My linkmeter was working fine (I used 4 probes on it to monitor a brisket cook last weekend that turned out great), except I did not have a fan yet. Well the fan showed up today, so I excitedly wired it up and plugged it in. The fan did not start and the LCD instantly turned off. So I immediately unplugged it, and unplugged the fan. Then I plugged the linkmeter back in without the fan and have the following issues:
- LCD isnt blank, its just very very dim (it didnt used to be)
- LED on the hetermeter board briefly flashes twice then stays off (I thought I remembered this stay on permanently from my initial build, but could be wrong)
- web interface seems to still be working fine / temp probes are still reporting correct temps

I opened the case, checked connections, smelled the board and looked for burnt components and cannot find anything. What could mis-wiring the fan possibly have wrecked on the board that would cause the LCD to be so dim?
 
Last edited:

Jackson Raygor

New member
Update: Everything (including the fan) is now up and working correctly. Except the LCD is still misbehaving (it was working perfectly prior to the fan incident).
I tried setting the lb to 1 and to 254 as recommended and it made no difference. I think the backlight is completely non-operational. I can read the LCD display in a dark room, so the rest of the LCD is still functioning.

It looks like the backlight is controlled by pins 15 (pow) and 16 (gnd). Which would make the possible failure points R13, Q2 or R7 (just a piece of wire on my board), SJ2 (what is SJ2?) or the LCD backlight unit itself.
How can I test the backlight unit on the LCD itself?

Thanks for the help,

Help, I messed up my linkmeter.
My linkmeter was working fine (I used 4 probes on it to monitor a brisket cook last weekend that turned out great), except I did not have a fan yet. Well the fan showed up today, so I excitedly wired it up and plugged it in. The fan did not start and the LCD instantly turned off. So I immediately unplugged it, and unplugged the fan. Then I plugged the linkmeter back in without the fan and have the following issues:
- LCD isnt blank, its just very very dim (it didnt used to be)
- LED on the hetermeter board briefly flashes twice then stays off (I thought I remembered this stay on permanently from my initial build, but could be wrong)
- web interface seems to still be working fine / temp probes are still reporting correct temps

I opened the case, checked connections, smelled the board and looked for burnt components and cannot find anything. What could mis-wiring the fan possibly have wrecked on the board that would cause the LCD to be so dim?
 

Bryan Mayland

TVWBB Hall of Fame
You can test the backlight directly by running +5V to pin 15 (from pin 2) and connecting 16 directly to ground (from pin 1). If that works that means either the BC337 is bad (this might be Q2, I don't have the schematic in front of me) or one of the traces is blown on the PCB (which you can route around). If the backlight still doesn't come on, something on the LCD is bad so you'll have to rig up your own solution.
 

Jackson Raygor

New member
Thanks for the help, it turned out that pin 15 and/or 16 on the LCD didnt have a solid solder connection to the LCD board. Plugging in the fan to the RCA style plug must have pressed enough on the case/cable/etc to break them loose. Resoldered them both and everything is working great. Thanks for the troubleshooting help.
 

MMatthews

New member
I have been watching these threads with great interest, and built 3 heatermeter systems. I have also purchased2 pi systems, ordered 3 boards for the pi systems, and bought a linksys 54gs router. The issue I have is the router came with dd-wrt installed, and I can't revert it. I was watching ebay for some more routers, and reading up on openwrt. Lo and behold, you can install openwrt on wrap boards. Just imaging. I have on hand, about 50 wrap boards. My questions is, do you install openwrt on the wraps first, on a generic linux system. I have been searching on how this can be done, with no avail. If I can get these boards to work, I may have an outlet for these bookend wrap boards.
 

John Bostwick

TVWBB Wizard
I have been watching these threads with great interest, and built 3 heatermeter systems. I have also purchased2 pi systems, ordered 3 boards for the pi systems, and bought a linksys 54gs router. The issue I have is the router came with dd-wrt installed, and I can't revert it. I was watching ebay for some more routers, and reading up on openwrt. Lo and behold, you can install openwrt on wrap boards. Just imaging. I have on hand, about 50 wrap boards. My questions is, do you install openwrt on the wraps first, on a generic linux system. I have been searching on how this can be done, with no avail. If I can get these boards to work, I may have an outlet for these bookend wrap boards.

As to the DD-wrt router, if you first revert it back to the stock firmware and then you can install Openwrt. You may need to get router tools Router tools I have a couple routers that have had DD-wrt and I have converted them to Openwrt. As for your other questions, I cant help you, but someone one on here surely could.
 

Bryan Mayland

TVWBB Hall of Fame
Lo and behold, you can install openwrt on wrap boards. Just imaging. I have on hand, about 50 wrap boards. My questions is, do you install openwrt on the wraps first, on a generic linux system.
I don't even know what a wrap board is. Can you provide a link?
 

Bryan Mayland

TVWBB Hall of Fame
Wow those are pretty nifty, I had never heard of them before. It looks like the serial port is RS232 so you'll need to build a converter to interface to the HeaterMeter using a MAX232 or similar converter chip. It might be more trouble than it is worth considering the low cost of the Rasberry Pis.
 

MMatthews

New member
I didn't realize the serial was a different protocol I just saw tx, rx, ground and the serial port settings for the heaterboard. Is there any way to integrate the old 3.2 boards to the pi's?
 

Bryan Mayland

TVWBB Hall of Fame
Yeah the serial port on the WRAP looks to be a standard good-ole serial port which means its voltage levels are like +18/-18V or whatever they are. HeaterMeter and the routers all do TTL-level serial, which is 0V/3.3V. Hooking one to the other would almost certainly fry the HeaterMeter.

The HM 3.2 board's RX/TX can hook up directly to the RX/TX pins on the Pi, they're the same voltage level. The AVR on the V3.2 boards runs at 5V though and the V4.0 boards are 3.3V. Technically you could remove the LM7805 regulator, and hook up the +5V from the Pi to the HeaterMeter to power it. You'd need to populate the 12V barrel jack to still provide 12V for the fan operation as well as have a USB power supply for the rPi/HM boards. I haven't really thought it all the way through, but that's the basics. If someone was planning to do that then they should understand how the two boards work before trying to just hook them up.

Also, the avrupdate uses the board type to determine the communication method to invoke hmdude with to flash the AVR firmware. So if you did this, you'd have to do any AVR firmware updates manually or edit the avrupdate script.
 

Nathan L

New member
Does anyone still have a spare v4 board I could buy off them or should I just order 3?
Thanks, and thanks for making this awesome project!

Edit: I went ahead and placed an order with Osh Park for 3, so I will have a couple extras in a couple weeks.
 
Last edited:

Bryan Mayland

TVWBB Hall of Fame
So, if one was to try to use a dlink dir-601 that has openwrt installed already, what would the steps be?
Basically you just need an OpenWrt that is compatible with the libraries used and then there's just the 3 custom packages: librrd NOGRAPH, rrdtool NOGRAPH, and linkmeter. Everything is sort of geared towards the Attitude Adjustment OpenWrt release. I thought it was coming out a lot sooner than it was (heck over a year later and it still isn't released yet) so unfortunately things don't just work on a Backfire release. Double unfortunately "For most devices using brcm47xx images is fine, but older models with only 16 MiB RAM or slower CPUs (200 Mhz) will not run properly with it" that almost specifically points to WRT54GLs so I'm not sure I'll ever get Attitude Adjustment final images for LinkMeter on the WRT54GL.
 

 

Top