Hello makers! The schematic presented in this project is actually a constant current source to which a current limiting section composed of Q1, R2 and R3 has been added. The moment the current required for charging is exceeded, it is diverted through Q1 and the output voltage drops. The output voltage is: 1.2x (RV1+R5+R4)/R4 volts. The current limiting occurs when the current is approximately 0.6/R3 amps. For a 6V battery that requires a faster charge, the charging voltage is 3x2.45=7.35V (3 cells, at 2.45V per cell). So the total value for R5+RV1 is then about 585 Ohms. For a 12V battery the value for R5+RV1 is 1290 Ohms. For the power supply to work efficiently the input voltage must be at least 3V higher than the output voltage needed to charge the battery. RV1 is a standard potentiometer capable of handling enough watts for the application in which the circuit is used. The LM317 must be cooled with a sufficiently large heat sink (ultimately it depends on how much you ask of it). Except for the situation when the circuit is used for charging car batteries or accumulators, it can also be used as a stabilized voltage source in various applications. The diode bridge D1 is rated at 2A, and the transformer is a voltage drop from 230Vac, I don't know what voltage it has in the secondary but I trust that I did it correctly. Gerber files and BoM for PCB are available in the download section as well. Enjoy it! 🤓 I just designed the PCB for my own use, I am not the original author so check the source link. *Source: https://2.bp.blogspot.com/-ZEuHsBYY0IY/VtiDgHi8ouI/AAAAAAAAONM/aonvi6pJgT4/s1600/Incarcator%2Bbaterii%2Bauto.gif

Hi makers! This time, the PCB color is very important for the project I want to build. I had a white PCB made at JLCPCB that features many LEDs in white packages as well. I plan to build a more animated and at the same time more interactive panel, practically the easiest way is to do this using LEDs, but not just any LEDs, but the addressable WS2812B ones. Why wouldn't I use LED strips? Because they don't produce the desired effect, I've tried this in the past, by just sticking an LED strip on the interior walls I don't get a really good looking panel. That's why I want to use PCBs because I will basically have a perpendicular view over the LEDs. I was inspired by the classic LED matrix, basically the panel is built from PCBs but in the shape of a hexagon, placed together, on which I place 144 LEDs and capacitors. I thought of separating the panel like this 6+4, meaning 6 PCBs placed vertically on 2 columns to create a kind of waterfall effect, I will have to experiment with SW libraries, FadeLed rather (to obtain a Matrix-like effect), and the other 4 PCBs will be placed in such a way that the overall appearance of the panel is not too linear, having different, more dynamic and diverse effects. I will also need an enclosure for these PCBs, this is where 3D printing comes in, which allows me to build enclosures the way I want, on a puzzle model. I have a friend who owns a printer. The cover will be white, but I will have to experiment when I have the PCB with LEDs, I will try to make the panel hangable but at the same time placeable on a table stand for example. But I will have to make durable joints because it will add some weight. For the power supply I will need a 5V with high current capability, because these LEDs will consume some current. Now, addressable LEDs are not called that by chance, I will need a microcontroller, and for that I will use the well known Nano and Arduino IDE. This allows me to create some scenes or operating modes. I do not exclude the use of an ESP32 and control via phone, but the internet connection is unstable. Maybe things will improve along the way. 😁 For the interactive and control part I will start with a button/touch button to change the color of the 6 cascade PCBs, and the other 4 will have different effects (wheel, stars, Gaussian Pulse, etc). By experimenting I can even use an IR sensor or ultrasonic, which will allow me to control touchless. The manual work will mainly consist of soldering a lot of wires, each hexagon PCB would have 6 power points, which I have to gather in a single point at the power supply. Then there are 2 more wires that connect the PCBs. Fortunately there is no need for many wires connected to the microcontroller board. Maybe I can manage to get a good design in the 3D printing stage that does not involve drilling holes, screws, but at the same time it has to be a solid design. f56c6b13f2214874807957972fd2221d.webp #PCB# #WS2812B#

Hi makers! This schematic represents an Adjustable Linear Voltage Regulator (Power Supply) circuit. Its primary purpose is to take a higher, DC input voltage and convert it into a lower, stable, and adjustable DC output voltage. Before sending a PCB off for manufacturing, I prefer to experiment using either a breadboard or a test board. In this case, however, experimenting on a breadboard is easy. After that, an order is placed with JLCPCB. 1. Core Component: LM1084-ADJ The heart of the circuit is the U1 LM1084-ADJ. Function: It is a Low Dropout (LDO) positive voltage regulator. Capacity: The LM1084 is capable of handling high currents (up to 5 Amps with a serious heatsink), making this a robust power supply compared to standard regulators like the LM317 (which handles 1.5A). 2. Input Stage • J1 (9-20V): This is the input connector. It accepts a DC voltage between 9 Volts and 20 Volts. • C1 (330uF) & C3 (100nF): These are input capacitors. • C1 is a large bulk capacitor that smooths out low-frequency ripples from the power source. • C3 is a small ceramic capacitor that filters out high-frequency noise and prevents the regulator from oscillating. 3. Voltage Adjustment This is how the output voltage is controlled: • R1 (120R): This resistor is connected between the Output and the Adjust pin. It sets the reference current. A value of 120Ω is standard for these regulators to ensure a minimum load current (approx. 10mA) so the regulator stays stable. • RV1 (5k Potentiometer): This is a variable resistor connected to the Adjust pin. By turning this knob, you change the resistance, which changes the output voltage. The Formula: The output voltage is determined by the formula: Vout=1.25V×(1+RV1R1)V_{out} = 1.25V \times (1 + \frac{RV1}{R1})Vout=1.25V×(1+R1RV1). With a 120Ω fixed resistor and a 5k variable resistor, the theoretical range is roughly 1.25V to ~53V. However, since the input is max 20V, the output can never exceed the input (minus a small "dropout" voltage of ~1.5V). So the practical max output is around 18V. The label 3.3-16V on J2 indicates the intended safe operating range. 4. Protection Diode (Top) D1 (1N4007): This diode is a protection component. It is connected in reverse bias (Cathode to Input, Anode to Output). Function: If the input power is suddenly disconnected or shorted to ground, the large capacitors on the output side (C2) would try to discharge back through the regulator, which could destroy it. D1 provides a safe path for this current to flow back to the input side, protecting the LM1084 chip. 5. Output Stage • C4 (100nF) & C2 (100uF): These are output capacitors. They improve the transient response (how fast the regulator reacts to load changes) and ensure the output voltage is smooth and stable. • R2 (1k) & D2 (LED): This is a simple indicator circuit. When the output voltage is present, current flows through the resistor and lights up the LED, indicating the power supply is active. • J2 (3.3-16V): This is the output connector where you would connect your load (the device you are powering). This description was created partly using A.I. Most of the time I use salvaged components or buy from local store, but I tried to build a BoM for you too using LCSC.com supplier. The project is presented as is, made for hobby projects. Enjoy it! 🤓 #PCB# #LM1084#

Hi makers! Another PCB completed, and a different color chosen—blue. I created a simple, minimalist PCB (again via JLCPCB) that allows me to use a microcontroller from the ATMega family. I made this minimal platform for me, I can use it with an ATMega8 or ATMega328 microcontroller, or any compatible microcontroller. I made a simpler version, giving up the programming circuit via USB and others, like voltage regulator, resulting in a PCB that allows us access to the GPIO of the microcontroller. For microcontroller programming, you can use a method similar to that of Arduino platforms, load a bootloader in the microcontroller, and with an FT232RL TTL to USB adapter you can program the microcontroller very easy , as it is done on Arduino boards. There is also a green LED indicator on the PCB for voltage, and a red LED that we can use to load and run a Blink sketch. eb558b3f2c744803bf98c13f00515ba7.webp 1. Microcontroller & Clock Circuit (The Core) U1 (ATmega8A-AU / ATmega328): This is the brain. The schematic shows the TQFP-32 SMD package pinout. It is compatible with both ATmega8 and ATmega328 (pin-compatible for the most part). Y1 (16MHz Crystal) & C1, C2 (20pF): This is the external clock circuit. 16MHz is the standard speed for Arduino boards (running at 5V). The capacitors C1 and C2 are load capacitors required for the crystal to oscillate stable. 2. Power Supply & Indicators Decoupling Capacitors (C4, C5, C6, C7, C3): 10µF (bulk) and 100nF (high-frequency noise filtering) capacitors near the VCC pins (AVCC and VCC) and the AREF pin. This is crucial for stable operation, especially for the ADC (Analog to Digital Converter). D3 (Green LED) & R3 (1k):Power Indicator. It is connected directly to VCC (through a current-limiting resistor). It will light up as soon as the board is powered, confirming voltage is present. J6 (ICSP_2): Power header (VCC and GND), likely used to supply power to the board or tap power from it. 3. Reset Circuit R1 (10k): A pull-up resistor keeping the RESET pin (Pin 29) HIGH (active state) during normal operation. SW1 (SW_Push): A tactile button that pulls the RESET pin to Ground when pressed, manually resetting the microcontroller. Auto-Reset Circuit (C8, D1, "PTR" net): The label "PTR" connects to the DTR (Data Terminal Ready) pin of your FT232RL adapter. C8 (100nF): This capacitor couples the DTR signal to the RESET pin. When you open the serial port to program (like in the Arduino IDE), the DTR line pulses, pulling RESET low momentarily to put the chip into the bootloader. This allows for "Auto-Reset" programming just like a real Arduino. D1 (1N4148): This diode is there to protect the reset line or ensure fast discharge of the capacitor C8 when the button is pressed, preventing conflicts between the manual button and the auto-reset circuit. 4. User Interface (The "Blink" LED) D2 (Red LED) & R2 (1k): LED for testing. Note on Pinout: On an ATmega328, PB1 corresponds to Arduino Digital Pin 9. Standard Arduino Note: The standard "Blink" sketch usually uses Pin 13 (PB5). Since your LED is on PB1 (Pin 9), you would need to change the pin number in the Blink sketch to 9 (or define LED_BUILTIN 9) to see it blink, unless you have customized the bootloader/board definition. 5. Connectivity & Headers (GPIO Access) The main purpose of this board is to break out the pins. J1 (Pins_Left) & J3 (Pins_Right): These headers break out almost all the GPIO pins (Port B, C, D) and Analog pins (ADC6, ADC7, AREF). This allows you to easily connect sensors, modules, or wires. J2 (ISCP_1): This is the ICSP (In-Circuit Serial Programming) header. It exposes PB3 (MOSI),** PB4 (MISO), and PB5 (SCK)**. This is used to burn the bootloader initially using a programmer like a USBasp or AVR ISP. Once the bootloader is installed, you can switch to using the FT232RL method you described. The circuit description was created using A.I. *****The circuit is presented as is, made for hobby projects. #PCB# #Microcontroller#

Hi makers! One of the most fundamental problems in robotics is controlling the speed of a DC motor. The most common speed control method is PWM (Pulse Width Modulation). Pulse Width Modulation is the process of varying the power delivered to a device by switching it on and off at a specific frequency. These on/off switching intervals are referred to as the "Duty Cycle." The diagram below shows waveforms for 10%, 50%, and 90% duty cycles. https://electrodb.ro/control-turatie-motor-prin-varierea-factorului-de-umplere-pwm/ Thus, the duty cycle describes the pulse width as a percentage. A 10% duty cycle means the device receives current for 10% of the cycle, while it receives none for the remaining 90% of the time. A 100% duty cycle means the device receives current continuously, rendering PWM unnecessary. These signals are sent to the motor at a sufficiently high frequency so that the pulsing itself does not adversely affect the motor's operation. The end result of the PWM process is that the total power delivered to the motor can be adjusted from 0% to 100% duty cycle, ensuring high efficiency and stable control. In the PWM circuit, the 555 timer is configured as an astable oscillator. This means that once power is applied, the 555 will oscillate without requiring any external trigger. Circuits of this type allow for motor speed control ranging from 0% to 100% while maintaining constant torque. In principle, the NE555 circuit generates a signal at a specific frequency that is applied to a monostable stage, the timing period of which is determined by the value of a resistor. While N-channel transistors can be used, circuit variants employing P-channel transistors also exist; the difference in the latter case is that the load is placed between the source and the power ground, while the drain is connected to the power rail (the positive voltage supply). I just designed the PCB for my own use, I am not the original author so check the link source. Source: https://electrodb.ro/control-turatie-motor-prin-varierea-factorului-de-umplere-pwm/ This project is presented "as is" and is intended for personal use. Most of the time I use salvaged components or buy from local store. I think you can easily tell who I had this PCB made by (*manual assmebled). 🤓😁 #PCB# #NE555#

Hi maker! I believe most of us use a light source when we can't see anything around us; thats why Im presenting a simple circuit—one that is both practical and a fun project to build. I modified the author's original schematic because I wanted the LED to light up when the room is dark. Before sending a PCB off for manufacturing, I prefer to experiment using either a breadboard or a test board. In this case, however, experimenting on a breadboard is easy. This project is presented "as is" and is intended for personal use. Most of the time I use salvaged components. I just designed the PCB for my own use, I am not the original author so check the link source. Source: https://www.iot-experiments.com/power-on-a-circuit-when-the-lights-are-on/ #PCB# #LED#

Let me also show you a lighter PCB color: yellow. Its the only shade available from JLCPCB, but its actually quite good and uniform—meaning there are no spots or imperfections—even though its a PCB with a lot of traces. I salvaged an electronic board that contains an AT90CAN128 in a QFP package. Initially I thought it was an ATMega128 MCU (I also use an ATMega328, but I don't know all of them 😅), but then I did a search on the internet and discovered that it is a similar MCU that has some extra capabilities. I plan to use this MCU to create a programmable board, through methods known to me, that is, by consulting the internet (forums and so on), and I even found information to program it using the well-known Arduino IDE (and from here we all know what a wide world has formed around Arduino 🤓), but I also have difficulties on this path. Given that the MCU I found is in an SMD package, I cannot use it in optimal conditions on a test wiring, perforated, so I need to design a good PCB. t will be a 2 layers PCB, it is relatively minimalist, in the center of attention being the AT90CAN128, and next to it I will place male pin headers to facilitate access to the GPIOs. This is the electronic circuit (quite complicated to understand 😆😅): Maybe you think the dimensions are a bit generous, but I don't mind, it's one sample. Let's not forget the bill of materials, except for the pin headers, of which I don't have many, the rest of the components are recovered from other electronic boards. Regarding the other components (resistors, capacitors) I will use both SMD and TH, I have them on hand (just what I said at the beginning). This board will be powered by 5V, so it's definitely handy, plus many electronic modules work at 5V. With the help of the Arduino IDE and the available libraries, I will install the board and program the AT90CAN128 via a USB AVR programmer (from the MCU I need the signals: Reset, Mosi, Miso, Sck). What I can do next I have many options, if I have a board with many ports I can use it with environmental sensors, 16x2 display, common modules after all. I have enough ports to attach many LEDs, and for some time I have been thinking about an application with TTP223 touch buttons and RGB LEDs, to create a dynamic light panel or a small table, depending on resources (3D printing would also be needed and this part is a bit tricky) and time. But I also have a more feasible and equally brilliant alternative, 4x4x4 LED cube.In the end, I think that the outline of an application goes something like this: e002ed22dc7b468993c1db60fec6186e.png So, to successfully build this board I would need: Manufacture a professional PCB; Assemble the components that I recovered from other boards; Check the programming instructions with Arduino IDE and software libraries; Take out the USB AVR programmer from the monkeys box 🙈. So, after solving all the above, I still have to experiment with the programming tools and then we are ready to go.

Just a quick tip—in case anyone hasn't noticed this yet—JLCPCB and LCSC share something in common: they use the same part numbers, meaning you can search for components on both sites. They also use the same Manufacturer Part Number (MFR/MPN), so you can be certain you won't mix anything up. quick-tip-for-components-searching-v0-3s3tiv9a78th1.png?width=1366&format=png&auto=webp&s=940d97aa4407958826788a19cbaa40815de556d8 Search on LCSC quick-tip-for-components-searching-v0-mwsdr24c78th1.png?width=1423&format=png&auto=webp&s=c9989aed810be848dc764d59d84b82e59be40e44 Search on JLCPCB 👍😉

We've reached the next color, purple, which also coincides with the largest PCB I've made at JLCPCB, about 200mm*70mm. Initially I experimented with a homemade PCB, obviously aesthetically it didn't turn out too well, but I wanted to make sure the project didn't have any bugs (I still make mistakes 😅). It is a panel with five 5x8 matrices and MAX7219 drivers; I am going to use it with an ATmega328 microcontroller. Who else has chosen this color? #PCB# #Color#

I wanted to try out all the PCB colors, and I did just that. Continuing on from my previous post, I come with a PCB that I have made over time at JLCPCB, the color is green, probably the most common option and yours, I could say basic option. I won't talk much about the PCB, it's a simple adapter for the ESP-01/S module. 🤓 *I know my phone camera isn't great, so the color might appear a bit too dark to you. #PCB# #Color#

Since I know I’ll be finishing my project soon and am always looking to save money, I just wanted to remind you that if you install the JLCONE software from JLCPCB on your PC and place an order, you can get a discount of between $1 and $20; the amount is random, but it’s definitely worth a try. I recently placed an order myself and got a $2 discount, which helped me out. 👇👇👇 https://jlcpcb.com/news/jlcpcb-jlcone-desktop-app Good luck! #PCB# ##JLCONE##

In case anyone is still wondering what color to choose for a PCB, below are photos of my PCB (made by a hobbyist). Just curious—does the chosen color have anything to do with your project's intended use? 🤓 Since the PCB I designed is related to temperature, I chose the color red. #PCB# #color# Overview This circuit is a linear, temperature-controlled fan driver. Unlike simple on/off thermostats or PWM (Pulse Width Modulation) controllers, this circuit varies the DC voltage supplied to the fan smoothly. This "linear" approach eliminates the high-frequency switching noise often associated with PWM and prevents the "coil whine" that occurs when fans are run at very low voltages where they struggle to spin. Key Functional Blocks 1. Temperature Sensing (The Input) Components: TH1 (10k NTC Thermistor) and RV1 (10k Potentiometer). Function: These two components form a voltage divider connected to the base of transistor Q1. TH1 (NTC): An NTC (Negative Temperature Coefficient) thermistor decreases its resistance as temperature rises. RV1 (Pot): This allows the user to manually set the temperature threshold (calibration). Logic: As the device gets hotter, the resistance of TH1 drops, changing the voltage at the base of Q1. This signals the circuit that cooling is needed. 2. Control & Error Amplification (The Brain) Component: Q1 (2N5401 PNP Transistor). Function: Q1 acts as the control element. As the temperature rises and the base voltage drops (due to the NTC), the PNP transistor turns ON more heavily. It amplifies this small change in temperature into a control signal that drives the power MOSFET. 3. Power Driving (The Muscle) Component: Q2 (IRF540N N-Channel MOSFET). Function: This is a high-power transistor that handles the actual current for the fan. Instead of acting as a simple switch (fully ON or fully OFF), it operates in its linear region (acting like a variable resistor). As Q1 conducts more current, it increases the voltage at the Gate of Q2. This lowers the resistance between the Drain and Source, allowing more current to flow through the fan. This results in the "smooth ramping" mentioned in your text. The fan speed increases gradually rather than in steps. 4. Hysteresis (Stability) Components: R1 (100k) and R5 (220k) (and potentially the interaction with R3). Function: The text mentions "shutdown hysteresis prevents frequent cycling." Without hysteresis, if the temperature hovered exactly at the threshold (e.g., 40°C), the fan would rapidly turn on and off (chatter), which is annoying and wears out the motor. The feedback resistors (likely R1 and R5) create a "lag." Once the fan turns on, the threshold temperature for turning it off is lowered. For example, it might turn on at 45°C but won't turn off until the temperature drops to 35°C. This creates a stable "dead band." 5. Coil Whine Prevention (The Zener Diode) Component: D1 (5.1V Zener Diode). Function: The text states the circuit "avoids applying voltage just at the threshold... preventing... coil whine." Fans often make a buzzing or whining noise at low voltages (e.g., 1V–4V) because the magnetic field isn't strong enough to spin the rotor smoothly; it just vibrates. The 5.1V Zener diode likely sets a minimum voltage threshold. The circuit is designed so that the fan stays completely OFF until the temperature is high enough to drive the voltage past this 5.1V point. Once it turns on, it starts at a healthy speed (silent operation) rather than a slow, whining crawl. 6. Filtering Component: C1 (100uF Capacitor). Function: This capacitor is placed across the fan terminals (parallel to the fan). It smooths out any voltage ripple and provides a burst of current when the fan motor demands it (motors are inductive loads), ensuring stable operation and reducing electrical noise. Summary of Operation Cold State: The NTC resistance is high. Q1 is OFF. Q2 is OFF. The fan receives 0V (or is disconnected) and is silent. Warming Up: Temperature rises. NTC resistance drops. Q1 begins to conduct. Activation: Once the threshold is passed (and the Zener voltage is overcome to avoid whine), Q2 begins to conduct. The fan voltage ramps up smoothly from ~5V to 12V. Hot State: Q2 is fully ON (low resistance). The fan receives the full 12V for maximum cooling. Cooling Down: As temp drops, the fan slows down smoothly. Due to hysteresis, it stays on slightly longer than it would in a simple on/off circuit, preventing rapid cycling. The circuit description was created using A.I. Source: *https://www.youtube.com/watch?v=YGpXFbxD_Wk&ab_channel=REDShade* I did not create this circuit, I just designed it for my own use.