Re: Need LAN connection over several hundred meters - how to do this?
The problem I see with checking temperatures, PCR tests, vaccines (when they materialize), [I]etc.[/I] is it leaves folks with a false sense of security: "I'm not running a fever so I must not be sick".
Each time I go to the library or a medical provider's office, they check my temperature (noncontact thermometer). It ALWAYS reads a degree or more lower than my actual temperature. Huh??
A more effective solution is widespread testing -- often. "You were...
Curious.George
Badcaps Legend
Last Activity: 11-07-2020, 07:27 AM
Joined: 11-01-2011
Location: Unknown
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Re: Need LAN connection over several hundred meters - how to do this?
There are other frequency bands that may also be available to you (sorry, I don't know what's "legal" where you reside).
You can also buy "extended power" WiFi access points. These aren't legal in the US but may be where you are. In free air. locating one centrally may easily allow you to bridge the distance between "devices" (again, I'm thinking along the lines of separate in and out "devices")...Leave a comment:
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Re: Need LAN connection over several hundred meters - how to do this?
And folks who are infectious aren't necessarily hot!...Leave a comment:
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Re: Need LAN connection over several hundred meters - how to do this?
I only suggested that as a quick/easy way to see if the technology would work for you.
First google link: [URL="https://www.esteem.com/horizon-900-main-page/"]https://www.esteem.com/horizon-900-main-page/[/URL]
And what if they CAN'T access the mains? E.g., running the kit off a small genset (or even batteries!) Or, the branch circuit in one spot is entirely different from the one used elsewhere?
It's not just the hassle...Leave a comment:
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Re: Need LAN connection over several hundred meters - how to do this?
[I have no idea as to your costs, budget, etc.]
As I see it, your problem is that the cameras are high bandwidth devices to the PC. You "need" a hard connection between the PC and camera(s).
But, the INFORMATION that you are managing is really just "how hot is this body" and "how many bodies have gone in/come out".
This is a LOW bandwidth channel.
Imagine locating "smarts" (a PC) at each camera (or...Leave a comment:
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Re: NAS boot issue
It's not part of my "job" (I'm not an IT person). Rather, I have a sh*tload of stuff that I preserve as a consequence of designing hardware/software (for decades).
As a "normal person", I'd typically just be buying bigger disks for my "PC". But, why would I want to keep all that stuff on "my PC" when most of it is for legacy purposes (do you have your tax returns on your PC? Or, have you archived them, somewhere?)? And, once you get beyond a few TB, it's just not convenient to store stuff INSIDE...Leave a comment:
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Re: What do you repurpose server PSUs for?
I have a pair of them (85A @ 12V -- 1000W) that I've stacked to form a 24V supply for an electric wheelbarrow (previously was an electric wheelchair so it goes forward/backward, left/right as well as "dumps" the load). As it never leaves the yard (and, thus, can always be within reach of a long extension cord), it's silly to put 75AHr batteries in the thing! (you usually have to modify the supplies to isolate GND from CHASSIS else you end up shorting one out when you stack them)
I know some folks...Leave a comment:
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Re: NAS boot issue
Sorry, I just noticed your location. We think nothing of having "extra computers", here.
Unless you are really hammering on your NAS, you can usually opt for a less capable "PC" to host the software. I've used "diskless workstations" with external USB drives to expand storage. They (the workstations) are often fanless -- as are the external drives.
I just pulled two [URL="https://support.hp.com/us-en/document/c03235347"]T610's[/URL] out of my stash (I rescue these as there is little...Leave a comment:
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Re: NAS boot issue
My advice? Do yourself a favor and repurpose an old PC as a NAS. There are several "free" packages that you can load on generic hardware and get these features (often MORE features than a "proprietary" NAS).
[FreeNAS comes to mind. There are others.]
Then, worry about how you can transfer the contents of those images to the NAS. (there are some tools available that purport to be able to read many NAS images -- for recovery, only!)
The advantage that this approach has is you can replace...Leave a comment:
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Re: NAS boot issue
You have to very [U]carefully[/U] review the process that is prescribed. Little changes can cause it not to fail (e.g., having the network cable plugged in may change whether or not the process works; failing to hold down any magic buttons at the correct time; etc.)
The LEDs associated with the LAN may be driven entirely by hardware. I.e., they may simply reflect the signals detected on the network connector. Don't assume the processor is actually involved.
You can use a network monitor to see if there...Leave a comment:
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Re: Custom control board for TVs?
The electronics inside the TV have to do a few things:
- receive cable/OTA broadcasts
- drive speakers with the associated audio
- decode the "video" into signals appropriate for the LCD panel in use
- interact with the user (buttons, remote control)
Beyond that, sets typically include:
- support various audio-video CODECs
- support on-line services
- support updates
Most (all?) TVs are unsupported in very short order. So, a particular A/V CODEC...Leave a comment:
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Re: NAS boot issue
Some NASs have software that resides on one (or more) of the drives. Firmware on the "motherboard" just loads this into the system's memory. (this isn't the case for all NASs as the FLASH complement is increasing and, with it, the amount of cruft that can be crammed into the FLASH image)
For such a system, a defect in the FLASH contents (firmware) OR the image stored on the disk(s) leaves you with a non-functioning NAS.
In some cases, the firmware will fallback to relying on a TFTP service (or comparable)...Leave a comment:
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Re: Server emulation??
Likely impossible. If they've set things up to push you to their server (to retrieve your save data) when they could have also given you a local option, then they really WANT you to be tied to their service.
Note that it's typically not just a case of capturing the data on its way across the network; if they want to lock you in, they've likely used an encrypted tunnel and custom protocol to prevent you from actually accessing/viewing the data in transit. (the encryption keys would be embedded in the console)...Leave a comment:
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Re: Remote pump control ideas.
You don't need interrupts. In my example, you LIKELY would have them to provide the timing information. But, you could also implement delays using a real timer.
The point is that you can write your code largely ignorant of the fact that other "programs" (tasks) are co-executing alongside you -- assuming you take precautions not to have two (or more) trying to use the same resource(s) at the same time.
The downside to the "super loop" approach is that you have to remember to EXPLICITLY...Leave a comment:
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Re: Remote pump control ideas.
That's not the case with [I]preemptive[/I] multitasking. And, many nonpreemptive systems can run "endless loops" as long as there is some transfer of control to the OS within that loop ([I]i.e.[/I], any system call).
[CODE]task_t winky(void)
{
while (FOREVER) {
LED = ON;
sleep(1000ms);
LED = OFF;
sleep(1000ms)
}
}
[/CODE]
"works" because the sleep() traps to the OS -- which can take steps to transfer control to...Leave a comment:
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Re: Remote pump control ideas.
IIRC, the network drop comes in over fiber -- any sourced power would have to be available locally (in which case, why not let the MCU use it directly?)
That's been the case for many years, now. But, you're talking about SoCs, not legacy "MCUs". Much of the information in the datasheets deals with peripherals. And, the nitty-gritty details of the processors themselves are really only of interest to people writing OSs or programming on bare metal (where you really DO need to know how your code...Leave a comment:
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Re: best cheap/free scores 1.1
Today, I recycled 6 Smart-UPS 1500s as a token offering to the "God of Equilibrium". I figure I still need to shed some more volume and mass. But, that was a good start.
What I [U]really[/U] need to do is take another pass through all of my books and paper notes...Re: best cheap/free scores 1.1
Today, I recycled 6 Smart-UPS 1500s as a token offering to the "God of Equilibrium". I figure I still need to shed some more volume and mass. But, that was a good start.
...Leave a comment:
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Re: Remote pump control ideas.
That's how a client-server system operates. The server exports a service. Clients make demands on that service.
DNS is a service. A client sends a request to the DNS server: "Give me the IP address associated with Google.com". The server responds with the appropriate "answer".
HTTPd is a service. A client (someone using a web browser) issues a request to a particular HTTPd server: "Give me your top level index.html page". The web server responds with a copy of that page....Leave a comment:
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Re: best cheap/free scores 1.1
Cripes! I'm a sucker for "free"...
Time to see if there are any other things that I can add to my "scrap" pile to get rid of them, tomorrow!...
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Re: Remote pump control ideas.
My point has to do with whether the end of the fiber is "the other end of the link" (dedicated between "switches" and "pump") or, just a "network drop"?
In the former case, you "own the wire" and can do whatever you want without worrying about interference. In the latter, you can't directly control what is pushed down the "wire".
You want to ensure the "wire" is correctly carrying the "state" of the system:...Leave a comment:
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