This stylish pointer display is used to present data on the operation of the servers. It displays the percentage of CPU, RAM, and hard drive usage on your computer. The data is shown using three analog pointer-type devices - 10 V DC voltmeters (or any suitable ones, it is not a problem to choose a resistance for the full deflection of the pointer). The Raspberry Pi Zero module is responsible for controlling the operation of the system, along with a system consisting of two LM358 operational amplifiers powered by a 5> 12 V boost converter (ready-made module from Ali).
Wiring diagram
DAC circuit for op-amp 358 In order to connect voltmeters to the outputs, you need a simple program written in Python that generates three PWM signals in proportion to the load of this element of the controlled server. The op-amp circuit is an analog PWM voltage signal converter.
Parts board - 2 LM358 The DAC converts the 3.3V PWM signal from the Raspberry Pi into a voltage ranging from 0V to 10V. Analog Outputs 1, 2 and 3 are connected directly to the sensors on the panel, while PWM Inputs are 1, 2 and 3, connected to the controller.
Indicator design
The most difficult thing here is not to assemble a diagram - but to print beautiful 3 scales. Here is a picture that you can use for your device.
Drawings of the new scale of indicators Then cut it out and stick it on top of the native dial gauges.
Voltmeter scale View of the finished device
The indicators are mounted on a plate painted with gray paint. You can build it into the computer case, or you can arrange it as a separate prefix-box. The whole system is mounted in a compact case, so nothing can be seen from the outside, except for dial gauges.
Ready indicator — 3 pcs. Everything is powered by one common voltage of 5 volts from the PC power supply. On the one hand, it feeds the Raspberry Pi Zero, and on the other hand, through a 12-volt converter, a circuit for analog generation of a control voltage from 0 to 10 V for switchmen. The circuit and firmware of the MK is not given - since this is another story ...
Quote: "I bring to your attention another option on how to make an original hard drive load indicator. It is based on a change in voltage in the circuit, and converts these jumps into discrete values."
Led indicator
booting the hard drive -y for help
in creating a flash movie
Introduction
I’ll make a reservation right away: I’m not a modder, so I didn’t follow the canons of the genre. I am primarily interested in functionality, I care little about the aesthetic side.
I bring to your attention another option on how to make an original hard drive loading indicator. It is based on the change in voltage in the circuit, and converts these jumps into discrete values.
What is required for this:
Radioconstructor "LED level indicator". In Voronezh, it can be purchased for 55 r, which I do not recommend, since it is equipped with rather dim LEDs, and this money is not worth it. The only useful thing is the circuit board. Parts will cost 15 rubles.
It is advisable to purchase a 2-10 kΩ trimmer instead of R1.
LEDs (minimum 5 pieces).
molex power connector (female). I combined my scheme with an existing device, so I didn’t need it. You can use any power connection method.
When connecting the circuit to 12 V, it is advisable to run the LEDs through resistors. It depends on what kind of LEDs you are using - five volts are unlikely to need resistors, but 3 volts - most likely yes.
Wires, insulation/heat shrink, soldering iron (max. 40W), soldering accessories, etc.
Notes
It all depends on the LEDs that you are going to use (every psycho has his own program :-), more precisely on their price. Personally, I used an LED ruler for 32 rubles. In total, all this cost me 90 r, and for me, the mod is worth the money.
In general, I want to say that this radio designer is not ideal - the more LEDs glow, the dimmer they glow. The problem is partially solved by increasing the voltage (12 V instead of 5 V) and connecting the LEDs through resistors (470-510 ohms). But no one forbids trying another similar indicator - for example, you can search in "CHIP and DIP". So there is a lot of room for further development.
This scheme provides 5 discrete levels of indication. We can observe the similarity of this in the Winamp visualization in the "Spectrum Analyzer" mode.
Of course, for many, the first desire is to adapt this product for music, BUT ... Since I have enough indicators for music (and sounds in general), because instead of speakers I use the center, and it has a 7-band equalizer, and even in Winamp" There is none, so we will not engage in pop music and slightly diversify the scope.
The mod is quite simple and cheap in execution, especially for those who have been dealing with radio electronics for a long time. We will assume that everyone knows the soldering phase (editor's note: and whoever doesn't know, reads) - that is, they soldered the circuit, adjusted the power supply, distributed the LEDs by colors and pins (be careful - the circuit is non-standard!) - so let's move on to the first test.
If you buy a radio constructor, you should get something like this
Why "something" - because I slightly modified the circuit. I connected a blue LED so that it is constantly on (that is, separate from the circuit). It symbolizes the "cold" loading of the hard drive, that is, the zero level. I combined LEDs 2 and 3 to level 1, and LEDs 4 and 5 to level 2. I could initially use a 5 LED strip, but I made a mod with the future in mind if I suddenly find a circuit for 7-8 LEDs, for more accurate indication. The white electrolytic capacitor is not present in the original circuit, for me it acts as a voltage stabilizer.
We connect the power
Hint: If you take only one positive input with your fingers, then perhaps the first or second level will light up. This means the circuit is working.
Now we try to connect the inputs in parallel with the HDD Led (that is, usually the red dim LED, but you already have it DIFFERENT, right?). My LED is connected through a special connector (in the picture - white on the right), so it was not difficult to connect the indicator. Those who have LEDs soldered and insulated will have to tinker a bit.
Here was the first surprise. Initially, I wanted to use 5V power, but this circuit turned out to have one drawback (see above). When connecting the circuit to 12V (and adding resistors to the LEDs), the inputs connected to the HDD Led gave reverse currents, and made this same HDD Led glow half-heartedly. Perhaps due to the fact that I have a sensitive red LED (with which I replaced the original dim one). By removing the input ground (ground) from the circuit, I got the desired result. It's even better - less wires. If everything works fine for you with 2 wires connected, then leave it like that. (In the picture, the remaining input is the blue wire matching the red wire in the connector)
I want to note that this mod is not a complete replacement, but an addition to the main indicator. If HDD Led shows (relatively speaking) the channel load level (how large amounts of data are transferred), then the peak indicator displays how often (at what speed) data is transmitted over the channel. If you do not need to monitor the hard drive, then you can leave only the new indicator. Personally, I now have both indicators on the front of the system unit (for reference, the height of my LED bar is 4 cm).
Tuning
Most likely, your tuning resistor is small, and without a handle, so here we arm ourselves with a small (narrow) screwdriver, and start driving the hard drive. Personally, I took as a basis the operation of archiving small files (web pages), archiving large files (clips, for example), watching a movie through Windows Media Player, copying from one logical drive to another within the physical media. You can also try copying from one hard drive to another, or run Scandisk. We look at how the hard drive behaves, turn the resistor to set the range of indicator oscillations. In general terms, the point is to create different situations: weak loading of the hard drive (small volume in rare portions) and heavy loading of the hard drive (large volume in an almost continuous flow). In the first case, the peak indicator should twitch at level 1-2, in the second case, levels 1-4 will be on almost constantly, and level 5 will be on or blinking. Where to place the LEDs, the circuit, and so on - that is, aesthetic issues - it already depends on the imagination of everyone. Personally, I hid the circuit in the front box, and displayed the LEDs on the left side (on a grand scale for the future - I want to make a similar circuit for the Mobile Rack on the right).
Work illustration
Full load
HDD LED indicator in operation
high loading 
Average load 
Low load Zero load Additionally
Advantages of this mod
1.
Conceptually new element in the design - a great addition to any technogenic computer
2.
Some utility. Having two indicators has already helped me several times. For example, do not restart the computer once again (there was a suspicion that it hung - but the indicator twitched - and after 5 minutes the machine recovered!). Or vice versa, feel free to press Reset - the download LED was constantly on, and the peak was at zero - a sure sign of hang
3. Originality
Flaws
1.
The one that was described above in the article - the voltage is distributed between all working LEDs. However, at high voltages it is not so noticeable. Yes, and pulsation gives "aliveness" to a modified (and genetically modified :-) computer.
2. The very first question of everyone to whom I showed the mod: "Does it react to your music?" TIRED, honestly
You may need to buy a hard drive for various reasons: the volume of the old drive is small, the device is broken, you need an additional, portable drive, etc. Before buying, decide which device you need and with what characteristics.
External drives (HDD)
A portable hard drive is usually used to store a large amount of information, backup. Such a screw is small and easily connected to a computer. When choosing, you need to focus on the amount of memory (1,2,3 or 4 TB (terabytes) - the more, the better, but the higher the price. The form factor is no less important. If you need an external hard drive for a desktop computer, choose model 3 .5". For laptops, the 2.5 option is suitable. The performance of a portable hard drive is affected by data such as buffer memory and spindle speed. The higher these figures, the better.
SSD drives
These devices are much faster than conventional hard drives with a magnetic coating. It is also important to determine the volume here - for a regular, non-gaming PC, a 128 GB model is suitable. Pay attention to the speed of reading information, as well as the type of memory - MLC (more popular) or TLC (economical option with a small resource).
Indicator online store offers you a wide selection of hard drives from leading manufacturers:
- SiliconPower (Silicon Paver)
- Kingston (Kingston)
- Toshiba (Toshiba)
- Western Digital (Western Digital)
- Seagate
- CRUCIAL (Crucial)
- Corsair (Corsair)
- HITACHI (Hitachi)
- Plextor (Plextor)
- Patriot (Patriot).
You can buy a hard drive for solving any problems in all Indicator stores in Simferopol, Sevastopol, Evpatoria, Dzhankoy, Yalta, Krasnoperekopsk, Feodosia, Kerch and Saki. We provide fast delivery throughout the Crimea, as well as a guarantee for goods from the manufacturer.
With whom it has not happened: you leave the computer, after a few minutes you return - and the hard disk activity indicator blinks. What is he doing there? Looks, of course, very suspicious.But really, there's probably nothing to worry about. Computers with default Windows settings do this all the time. Although, of course, the possibility of infection cannot be ruled out, so it will not hurt to check the system with an antivirus for your own peace of mind.
The computer politely waits for its turn
In fact, the computer does not try to do nasty things secretly from the owner. On the contrary, he tries to be smart and polite. Windows needs to run a variety of service tasks in the background, and the system patiently waits for idle time (that is, the user leaves) to run them. This ensures that computer resources are not wasted on extraneous matters when the user needs them to work. If the system is being actively used, background housekeeping processes are suspended so as not to degrade performance.
So it's not a figment of the imagination: Windows is really waiting for idle time to start maintenance. And when the user comes back, service tasks usually stop, so it's usually impossible to figure out why the hard disk activity indicator blinked when idle. The Windows Scheduler gives you the ability to set the task to run exclusively during idle times, and many tasks are performed this way.
What is the computer doing when idle?
But what exactly is the computer doing in the background? The specific set of tasks depends on the system settings and installed programs, but the most common options can be listed.
File indexing. All modern operating systems are equipped with a file indexing function. They check each file (including its contents) and create a database that then instantly returns results when searched. For search to work, the indexing service must regularly check for file changes, and this may explain hard disk activity when idle.
Disk Defragmenter. In the days of Windows 98, you had to close all other programs to successfully defragment your hard drive. Modern versions of Windows defrag automatically in the background, but only when idle.
Scheduled antivirus scanning. Many antivirus programs and other security tools are set by default to automatically scan your system on a regular basis. Perhaps the activity of the hard drive is due to the fact that the antivirus is just checking the files stored on it.
Backup. If automatic backup is enabled (and it should be enabled!), hard disk activity may be caused by the file backup process.
Automatic update. Windows itself and many programs such as Google Chrome or Mozilla Firefox have an automatic update feature. If the computer is busy with something when idle, it is quite possible that it is just downloading and installing updates.
Of course, this is by no means a complete list. There can be an infinite number of options, depending on the specific set of installed programs. For example, if the Steam client is open in the background and an update has just been released for one of the games, the hard disk activity may be due to the download and installation of this update. File download programs, such as BitTorrent clients, can also cause disk activity.
How to find out what programs are using the disk when idle
In theory, everything is clear, but how to find out what the computer does in practice? First of all, if there is a suspicion of infection, it is worth scanning the system with a reliable antivirus, not relying solely on built-in tools. But if you just want to track disk activity, you can do that too.
You can find out which processes are using the disk using the Task Manager and Resource Monitor built into Windows. This is especially true if the disk activity indicator is constantly blinking, and the computer's performance has dropped for some reason.
To open the Task Manager, right-click on the taskbar and select Task Manager or press the ++ keys. In Windows 8, disk usage is displayed right in the Task Manager - you can click on the "Disk" column to sort processes by this parameter and see which one uses the disk the most.
Windows 7 does not have this option, so you need to open the Performance tab and click the Open Resource Monitor link. In the Resource Monitor window, go to the "Disk" tab - and you will see a list of processes that can be sorted by the degree of disk load. By the way, in Windows 8 / 8.1, the Resource Monitor also gives much more information than the Task Manager.
To track disk activity over time, you can use the Process Monitor program from SysInternals, a developer of useful utilities that advanced Windows users love so much. You can start Process Monitor and leave it running during downtime. Then, returning to the computer, you can see which processes used the hard drive in your absence.
Process Monitor logs any activity, but you can use the buttons on the panel to filter the list so that only file system-related events are displayed. For example, in the screenshot below, you can see that disk activity is caused by file indexing.
Process Monitor is good because it can show past activity. Even if a process stops using the disk or terminates altogether, information about it remains in the log. But it is hardly worth using this utility all the time, because event logging also creates a load on the system and, as a result, reduces performance. It should also be understood that Process Monitor keeps an event log only while it is running: if you start it after a surge in hard disk activity, it will no longer be possible to find out what exactly caused it.
The LED indicator (Light Emiting Diode, LED) of the hard drive operation (can be green, yellow or red) is usually located on the front panel of the case and serves to control the operation of the hard drive. Each access to the hard drive is accompanied by an indicator light, usually Indicators, switches and connectors 33
designated on the control panel of the system unit as HDD. Let it not scare you that the hard drive indicator does not burn constantly, but flashes periodically. The point here is not a bad contact, but a visual display of a quick access to the hard drive.
PC power indicator
The PC On light should always be on when the computer is turned on. The cable of this indicator is marked in most cases in green. This is a two-wire cable that terminates in a three-pin plug, with the middle pin not being used. The color of the cable corresponds to the color of the indicator - green-black or green-white cable.
Usually, the PC power-on indication cable is combined with the KeyLock cable (PC keyboard lock cable). In this case, the cable is supplied with a five-pin connector. Motherboard manufacturers usually label all connectors on the motherboard, so the appropriate terminal can be found without problems. The connection point of the KeyLock connector can be easily identified even without markings. Look on the motherboard for a single-row, five-pin bracket with one of the five pins missing. This missing pin is a kind of key for the correct connection of the connector.
Since this plug does not have guides, it is likely to be connected incorrectly. The result of this error will be no operation indication. In this case, you need to turn the plug 180P.
Mains switch Normally, the mains switch is already connected to the power supply. If this is not the case, you should use the instruction manual and connect it.
Attention!
When buying, pay attention to the fact that the switch is connected to the power supply. If there is no instruction, then entrust the connection of the network switch to a specialist. Due to the wide variety of power supplies, there is no single color coding for the power switch terminals. Be extremely careful when connecting it! We are talking about a mains voltage of 220-240 V.
By turning on the computer using the network switch, a cold start of the PC is performed, i.e. starting the system from rest (cold state). During a cold start, you should wait at least half a minute before turning on the computer again, because the mechanics of the drives require a certain time to completely stop.
Attention!
Frequently turning the computer on and off without pause using the network switch can cause serious damage to the disk drives and hard drive.
After turning on the PC, a self-test of the power supply is performed for approximately 0.3-0.5 s. If all supply voltage levels are within acceptable limits, the Power_Good signal is sent to the motherboard. This signal is sent to the motherboard, where the clock generator chip generates a signal for the initial setting of the processor.
In the absence of a PowerGood signal, the clock generator chip will constantly send a reset signal to the CPU, preventing the PC from operating with an “abnormal” or unstable supply voltage. When a Power Good signal is received by the generator, the processor reset signal will turn off and the PC test program (Power On Self Test, POST) written in the ROM BIOS will begin. After the successful completion of the test, the system will boot.
Some cheap power supplies do not have a Power Good signal conditioning circuit at all, and this circuit is simply connected to a +5 V supply voltage.
Some motherboards are more sensitive to Power Good signals than others. Start-up problems often arise precisely from insufficient delay of this signal. Sometimes, after replacing the motherboard, the PC stops working normally. In such a situation, it is quite difficult to figure it out, especially for an inexperienced user who thinks that the reason lies in the new board. But do not rush to write it off as faulty, because it often turns out that the power supply is "to blame": either it does not provide enough power to power the new motherboard, or the Power Good signal is not connected or formed incorrectly. In such a situation, it is best to try connecting the motherboard to a different power supply.
