2/16/2024

Liftmaster Garage door range issue

My garage door opener (Chamberlain Liftmaster pro 3280/3280-267) has been working fine up until I had my house and garage door painted (yeah I know that sounds odd).

Before the house was painted I could open the door from about 60 feet away with the 373LM remote, and about 100 feet with my Subaru homelink.

Now I have trouble getting the homelink to work at all, and the 373LM will sometimes work about 40 to 50 feet, and sometimes I have to get about 25 feet from the opener.

What I have tried:
new batteries in remotes.
running coax to an antenna outside the garage.
checking the openers circuit board for cold solder joints. re-soldering some even though they looked fine.
extending the antenna on the unit to a full wave length. removing the outside antenna I had installed earlier.
checked for interference on 315mhz (there is none) I have an SDR radio so I can look at a large chunk of the spectrum. nothing transmits within 1mhz of 315mhz (or really at all near me).

Replaced my LED bulbs with incandescent.
re-calibrating my remote. it was off frequency by 500khz. same for my wife's (hers is having similar issues).
purchased a Chamberlain 953EV-P2 which is supposed to work up to 1500 feet (it seems to work no better than the old remote). it is off frequency by 10khz (which is within spec).

I do not want to use a phone app to control the door as that is clunky.

One morning I had an appointment and took my portable SDR with me. I seem to be chasing multiple issues. while monitoring the SDR when I pulled out of the garage I tried to close the door with my subaru homelink which would not work I found that the homelink signal was very strong, distorted, and wandering all over the spectrum.

my old 373LM remote seemed to be dead (no signal on SDR).

the new remote worked fine to close the door.

After that I decided to do more checking for interference on 315mhz.

I didn't really see anything until I turned the gain and amplification all the way up on my SDR. the background noise level (per my sdr with all amplification off) is -85dbfs.

You can just make out a slight "throbbing" of about 1hz in the background noise that turns in to a hump from 308mhz to 327mhz when amplification is turned all the way up. I highly doubt this is causing a problem as it isn't even measurable normally. though I am intrigued as to what it might be. there is a military base 12 miles away, though I can't really pickup any radio activity from my house from there.

on another day I left the house to visit someone and had trouble closing the door and had to resort to using my alarm app. when I came home 7 hours later I was able to open the door from a reasonable distance with the newest remote.

I reprogrammed my homelink and had a lot of trouble getting it to accept the signal.

Drove home one day and could not get the door to open with any of the remotes at all. had to open with my app. I do not like using the apps because it way more involved than just pressing a button.

I found that what I thought was as dead battery in my 373LM was a cold solder joint on the main chip on the circuit board. The signal on the 373lm is all over the place but mostly within spec though sometimes will wander off by as much as 500khz. just to see if it would help I replaced the 4.7uf electrolytic with a new on which made no difference.

Pulled the main board in the opener this morning, found 3 electrolytic capacitors with high ESR. several that tested fine but I replaced anyways. there was one loose trace to one of the capacitors, don't know if I broke it or it was always like that.

Checked the cap on the power supply, it had a low ESR (which is good) I left it in since I did not have a replacement of that voltage. Resoldered anything that look suspicious under my video microscope.

I removed the original antenna and added a short coax lead going to a BNC connector so I can easily experiment with different antennas. yes there is strain relief. Antenna is half wave.


tested range and there seems to be a slight increase but I will have to test from the car at a later date.

Here are some things I found while working on this:

The older remotes use a tuning capacitor to align the signal. not 100% sure about this but it appears that they may tune the wide button at 315.5mhz instead of right on 315mhz as the Chamberlain FCC paperwork indicated. The FCC papers say that it is supposed to be 315mhz +/- .1% or 315khz FCC tolerance is .25%. if you want to find the paperwork google the FCC id and fcc the ID is on the back of the remotes. it's a somewhat technical read.

so the 3 buttons seem to be on slightly different frequencies. at least that is what it looks like on the spectrum from my SDR. If the wide button is on 315mhz then the other 2 will be at a slightly lower frequency separated by 100 or 200khz. This is true for the 953EV-P2, though this unit seems to be self tuning as there is no adjustments. all the remotes I tried have a signal that wanders, though the opener does not seem to care.

on my board there was a space on the circuit board for attaching a coax connector. I did not have one that was of the design but it is nice to know.

I have had a chance to test the remotes since working on the main board in the opener.

I was still having problems with the handheld remotes but my homelink in my car was back to normal after the opener re-learned it. it could open the door from about 50 feet away (which is about what it did before. Sometimes (before all this) it would work from 75 to 100 feet away in certain instances.

however mine and my wife's 373LM and my 953EV-P2 would still not work unless they were less than 20 feet from the opener (with the door closed).

I re-learned all the handheld remotes (before going somewhere) and coming back to the house my 373LM worked from about 50 feet away. I had not tested the other ones yet.

I suspect that with the failing capacitors and maybe something else I am not aware of it is possible that the memory on the opener got corrupted.

upon testing all the remote everything seems to be back to normal. so it appears it was multiple issues:
bad capacitors on opener PCB.
possibly corrupt memory in opener.
possible cold solder joints in 1 or more remotes and PCB of opener.

 Don't try to calibrate the remotes. without proper equipment you can put them way off frequency or they will not transmit at all. a tiny microscopic movement of the adjustment will put the signal WAY off. Do not make any adjustments to the tuning slug on the opener PCB (metal can with hole in the top). 

I was still not getting the range I wanted so I added an antenna connected by coax to the opener, the antenna was 36" long and put between the 2 garage doors. now I can open the door with my car homelink from the neighbors house in front of their garage.

1/31/2024

Dealing with solicitors of any kind

Are you tired of solar companies, exterminators, lawn services, religious organizations, or any other companies/organizations leaving flyers on your door, throwing bags of rocks/gravel in your driveway with flyers attached, knocking on your door, or in anyway soliciting you on your property?

good news, here is how to stop or reduce it:

check you local city ordinance and see if there is one regarding soliciting. If there is have a sign made with large bold letters that says NO SOLICITING followed by the ordinance in question. Post this where it is clearly visible. You can have these signs made on Amazon for not a lot of money.

When companies/organizations violate this you can try to report it, OR if you can identify the company leave a one star review explaining what they did, and quoting the ordinance in question. IF there is no ordinance just leave a 1 star review explaining what they did. You can try calling them but in most cases it will not do any good. they need a permanent reminder where everyone can see what they did.

This applies to churches soliciting is soliciting unless religious organizations are specifically exempted they cannot solicit you to come to their church if a sign is posted.



1/24/2024

Configure a computer to go to sleep and wake up again automatically

Recently I needed to put a computer to sleep and wake it up in the morning at a specific time, while keeping it logged in. Simple right? WRONG! The computer also had to be logged in.

First these instructions will not be detailed step by step (google it) and are not in the order I tried them, they are in the order that should work.

You will need:
scheduled tasks that run with highest privileges, one of which wakes the computer to run.
To configure Autologon if needed (google it).
A modernish computer that supports wake timers (in the bios) from a cmd line type:
powercfg /a
look for:
The following sleep states are available on this system:
    Standby (S3)
there might be others listed.
sysinternals psshutdown64.exe or psshutdown.exe
nircmd.exe... what's that? you've never heard of it? it's a wonderful command line program that does hundreds of very useful things. https://www.nirsoft.net/utils/nircmd.html
A batch file (we will discuss later).
Put all these files in a single non system folder.

Lets start:

disable any screensavers.
disable putting the computer to sleep automatically.
disable hibernate "powercfg -h off"

Stop Windows 10 from asking for password from sleep mode
In Settings, click on Accounts.
On the left side of the "Accounts" Settings window, click on Sign-in options.
Under Sign-in options, locate the drop down menu for Require sign-in.
select never

in regedit.exe under HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Power
add a Reg_Dword PlatformAoAcOverride set it to 0
this will disable "modern standby" S0. Because Microsoft hates you.

In an administrator cmd window issue this command:
powercfg -attributes SUB_SLEEP 7bc4a2f9-d8fc-4469-b07b-33eb785aaca0 -ATTRIB_HIDE
this will make a very important option visible. why is it not visible? because Microsoft hates you.

In control panel\power options enable wake timers, set "turn off display after" to never, and set "system unattended sleep timeout" (which you can now see) to a number of minutes that you want the computer to stay awake without keyboard or mouse movement (after a wake up) in my case 960.

Why? because microsoft decided that if you wake the computer and no one uses it in 2 minutes, it goes back to sleep. because Microsoft hates you.

To put the computer to sleep I created a task scheduler event and used sysinternals psshutdown64.exe file with the command "psshutdown64.exe -d -t 0".

Now the following solved the difficult part of getting the computer AND monitor to turn on.

create a bat or cmd file and add the following lines:

timeout /t 90
nircmd monitor on

if that does not work try:
nircmd async_monitor on
or
nircmd sendmouse move 1000 100

Create a task scheduler event that runs ONLY if the user is logged in (this is important), and wakes the computer to run. also in triggers set "stop task if it runs longer than" to 30 minutes. task scheduler may report the task running from the previous day. You may need to schedule a task that just runs this command 5 minutes before the wake up monitor command:

cmd /c "exit"

The scheduled event should run the batch file you just created.

now for the rant:
I needed a computer to:
autologon (if fully shutdown and then turned on).
keep the monitor on at all times.
keep the computer logged in at all times.
at a specified time put the computer to sleep in a state that it could wake up from and continue where it left off without having to login or restart programs.
wake up at a specific time.

the problems begin with the computer waking up but I had to manually login. Once that was solved the next problem was that the computer was not going to sleep in a wakeable state, it was going in to "modern sleep" (S0) which did not wake up properly. I needed the mode (S3) that shows a blinking power light. The computer cannot hibernate because hibernation requires a power button press to wake up. I could not use wake on lan because I did not want this to be reliant on another computer.

Microsoft does not want you leaving a computer running, and logged in because "muh security".

Microsoft put a hidden option so that if you commanded a computer to wake up and no one used it in 2 minutes it would go back to sleep (muh security). so I was getting the computer to wake up but it would go right back to sleep again.

If you don't enable wake timers then task scheduler cannot wake the computer to run a task.

I had to use sysinternals psshutdown because the more common (RUNDLL32.EXE powrprof.dll,SetSuspendState 0,1,0) command apparently does not work right and has never worked right.

The next major issue was that the computer would wake up but not the monitor. I tried using some simple VBS script (to issue key presses) I found on line but that did not work. there were some ridiculously complicated powershell scripts to move the mouse that I did not want to use either.

That's when I stumbled on nircmd. I powerful little stand alone program that does many many things. however it's command to move the mouse cursor did not work, nor did it's command to change display resolutions. I ran in to a problem where the nircmd monitor on would turn the monitor on and it would go right back off. I tried async_on and it did the same thing.The command that worked was a simple one: sendmouse move 1000 100. Sendmouse is different from the movecursor command.

the next step was to add a program that starts automatically after the computer is turned on or logged out and back in again.

however because this is an app from the microsoft store it is not intuitive.

the more common instructions:
select Start , then select Settings > Apps > Startup. Make sure any app you want to run at startup is turned On.

If you don’t see the Startup option in Settings, right-click (or select and hold) Start , select Task Manager, then select the Startup tab. (If you don’t see the Startup tab, select More details.) Right-click (or select and hold) the app you want to change, then select Enable to run it at startup or Disable so it doesn’t run.

didn't work because it did not show up there.

I finally found this set of instructions (works in 10 or 11):
https://www.elevenforum.com/t/add-app-to-run-automatically-at-startup-in-windows-11.6079/

1 Open File Explorer (Win+E).

2 Copy and paste shell:startup into the address bar of File Explorer, and press Enter to open your account's Startup folder.

3 Add or create a shortcut of any app, folder, drive, file, script, etc... you want to run at startup for your account into this Startup folder. Drag an APP from the start menu into that folder


There might have been other things I did, but I did not keep notes on everything, so if all this does not work for you I cannot help with that.