There are several benefits when integrating MQTT with Python for real time data visualisations. MQTT has been specifically designed for low-bandwidth devices as a light-weight publishing/subscriber protocol. To create a real-time visualisation of IoT devices using the Python programming language, paho-mqtt is a library that can be used to subscribe to sensor devices and stream in real time the data from those sensor devices into visualisation tools such as Matplotlib and Plotly.

The way this workflow works is you connect to an MQTT broker, subscribe to the relevant sensor device topics, and when the broker receives an update it sends an update to the subscribers (your Python script) which in turn automatically updates the visualisation of the data points using either Matplotlib or Plotly.

MQTT (Message Queuing Telemetry Transport)

Therefore, with an integrated form of Python and MQTT, users are able to create an easily accessible Dashboard that displays live data which is much easier to monitor and debug.

TLS (Transport Layer Security) is used to secure IoT devices through encrypted communications. In this case embedded hardware must use light weight libraries and have a proper way to manage recourses.Use the same secure key storage methods and secure elements (e.g., ATECC608A) to ensure that you cannot extract your private keys.

Ensure you are using the latest cipher suites (e.g., AES, ECC), and that you have a complete certificate validation process to help prevent MITMs. Handshakes in TLS require a large amount of resources therefore re-use sessions where possible and reduce the number of reconnections may help to save resources.

The purpose is not just encryption but also authentication and integrity of the device only communicating with authenticated servers.

The Critical Role of Ground Planes in High-Speed PCB Design: When developing a printed circuit board, the implementation of a solid ground plane is far more than a structural choice; it is a fundamental requirement for signal integrity.

Why Continuity Matters: In high-frequency systems, signals propagate as electromagnetic waves within a transmission line environment. A continuous copper plane directly beneath the signal trace provides a predictable, low-inductance return path. If this plane is fractured or interrupted, the return current cannot follow its ideal path. Instead, it is forced to "detour" around the gap. This deviation increases the loop area of the circuit, causing the electromagnetic fields to expand and bleed into neighboring traces. This mechanism is the primary driver of crosstalk and electromagnetic interference (EMI).

Empirical Evidence: A Comparative Study To quantify the impact of ground plane integrity, we can examine a laboratory setup involving two distinct PCB configurations. Both boards utilize matched 50Ω striplines, each terminated into a 50Ω load to the underlying ground plane. Each board features two connectors, labeled H1 and H2. The Experiment: A high-speed signal is injected into H1 (the "aggressor" line), while the signal on H2 (the "victim" line) is monitored on two different PCBs. The first one (PCB4) has an interrupting trace under both H1 and H2 while the second one has an interrupting trace only under H1 (PCB3). To do the experiment, two waveforms have been injected, a square wave and a sine wave both at 5V, and the peak-to-peak crosstalk voltage and its dependency on frequency have been found. Then, applying different frequencies, different data have been acquired.

Data analysis: From the data it is possible to notice how crosstalk is significantly higher for the PCB4 in both settings: square and sine waves applied. Also, with higher frequencies come also higher crosstalk.

Conclusion: When designing a PCB's layout, guaranteeing that one of the ground planes is solid without any cutting is actually very significant and can guarantee a good output of the PCB reducing crosstalk and thus disturbs.

#PCB##PCB# #PCB# #layout# #grounding# #loop# #current# #PCBDesign#

#decoupling# #capacitor# #pcb design# #JLCPCB#

Lately I have had this doubt: is the position of the decoupling capacitor really significant? Well, the quick answer is YES!

Here you will see a brief experiment and its results that I hope will make you understand how significant actually is.

First of all, what are decoupling capacitors and why are they needed?

• Well, they are needed to stabilize voltage and eliminate noise in electronic circuits by providing a local and high-speed reservoir for components (such as microcontrollers etc.). It will prevent the EMI radiation, as well as isolate the sensitive components from the power supply noise. More specifically, when a circuit needs current instantly the supply rails can't react instantly because of wiring inductance and resistance, thus the supply voltage sags. Putting a decoupling capacitor helps with this by keeping the circuits stable.

What do you need? 

• An oscilloscope, a signal generator and a power supply. The circuit built featured a NPN BJT transistor, with a resistor of 20 Ohm on its source, the gate connected to ground and drain to Vcc. Connected to the gate there was a source generator generating a square wave of 5V of amplitude at 1kHz. The source was connected to the scope/oscilloscope with DC coupling.
• After building the circuit with a breadboard, you can put a capacitor at difference distances from the voltage source and see its effect on the voltage drop.

Obtained data analysis

• the voltage drop without a capacitor is around 4.62V. This is HUGE! Since the voltage power is of 5V.
• the 1000uF electrolytic/ 1uF film capacitors are the one that reduced more significantly the voltage drop. Generally the electrolytic however are slower.
• the more the capacitor is near to the voltage source the more it attenuates its voltage drop.

Key findings from data

The experimental data reveals a critical struggle between power stability and signal speed. Without any decoupling, the 4.62V drop on a 5V rail represents a near-total power failure every time the transistor switches. In a real-world application, this wouldn't just be electrical noise; it would cause a processor to brown out or a sensor to provide false readings because the voltage hits rock bottom.

These results also expose a performance trade-off tied to internal resistance. The 1000uF electrolytic capacitor acts like a massive water tank with a slow, narrow valve. While it holds enough energy to prevent the voltage from sagging, it cannot release that energy fast enough to keep up with the 1kHz square wave. This explains why the signal rise time slowed to 153ns with the large cap, whereas the 1uF film version, acting as a smaller but much faster bucket, snapped the signal into place in just 90ns.

CONCLUSION

When designing a PCB's layout, ALWAYS put the decoupling capacitors near its voltage source, the nearest the better!

Do not put them distant!!

The Inverted-F Antenna (IFA) is an ideal option for 2.4GHz applications (Wi-Fi, Bluetooth) as it is small in size and performs well on basic 2 layer PCBs.

PIFA

An IFA acts like a quarter wavelength radiator. For 2.4 GHz the wavelength is approximately 125 mm so the actual radiating length will be 25 - 30 mm tall on FR-4 as a result of the dielectric material. However, because the antenna is housed on a PCB (which introduces dielectric loading), actual IFA length will typically range from 20-30mm in FR-4 material.

Three components make up the structure of an IFA:

1. Radiating Element/Main Trace
2. Shorting Pin/Trace To Ground
3. Feed Point Located Between The Other Two Components

The shorting component reduces the resonant length of the radiator and aids in impedance matching, while the feed location will allow for further fine-tuning of input impedance (targeted value of approximately 50Ω).

Proper ground plane design is also essential. The IFA should ideally be placed at the edge of the PCB with no copper and no routing underneath and around it (the keep-out area). The remaining area of the PCB acts as the ground plane; thus, the size and shape of the ground plane will have a large influence on performance.

Dedicate the entire bottom layer of a PCB with 2-layers as a solid ground plane and use multiple vias near both the feed and shorting locations to ensure a low-impedance path to ground.

Tuning is a necessary step that cannot be avoided. A small change in an object's length or width, or objects around the object, will affect the resonance. By including a π-matching network in the feed using two capacitors and one inductor, you can fine-tune your fabrication using a VNA after fabrication.

VNA

So what have we learned? Antenna design is split equally between calculation, layout discipline and tuning. Once you have your geometry and grounding right, you end up with an efficient, reliable antenna without having to rely upon elaborate multilayer boards.

PCB close-up

High-frequency circuit board design (microwave design) applies not only to radio frequency circuit board design engineers, but also to today's designers of circuit boards. Circuit board, or PCB, designers use microwave design principles as they reach frequencies of hundreds of MHz or more, where traces on Printed Circuit Boards (PCBs) are no longer behaving as simple wire connections, but will instead function as transmission lines.

Controlled impedance is an important concept in PCB design. Each PCB trace has a characteristic impedance that is determined by the construction parameters of that trace: Width, thickness of conductor materials, dielectric materials used as well as the distance to the reference or ground plane. Impedance mismatches (discrepancies between the characteristic impedances) create reflections/echoes and signal integrity issues in the form of signal loss and/or distortion. As a result controlled PCB geometric shapes must be closely adhered to; otherwise, you will create a signal integrity and performance issue.

Another important concept is return path. High frequency signals will follow the path of least impedance, which will normally be directly underneath the PCB trace (on the ground plane). Any type of discontinuity (for example, split planes) will increase the loop area and cause interference problems in the forms of radiated Electro Magnetic Interference (EMI).

Material selection is important too; standard FR-4 laminate will work on many PCB applications, but as you increase frequency you have increased dielectric losses. Therefore, in high frequency applications (i.e greater than 1GHz), it is common to select lower-loss laminates to maintain signal integrity.

In addition to using proper design parameters & materials, PCB layout techniques will change when designing high frequency PCBs. Design Engineers must consider design matching of trace lengths, effects of vias (splices in traces), and parasitic types of effects. Little elements within a PCB like stubs and sharp bends can have performance ramifications. Therefore, proper routing can be vital to achieving good signal integrity.

In conclusion, the use of simulation tools and measurement tools such as field solvers and vector network analyzers (VNA’s) are an important part of validating both pre-production and post-production designs.

The bottom line for microwave PCB designs is to help control the flow of energy through the circuit as opposed to simply connecting all points. By mastering these basic components of circuit design, you will now be able to produce circuits that function reliably and with superior performance at increasingly higher frequencies.

Three factors will aid you in your determination of which network is best for your IoT application: Coverage, power, and infrastructure.

LoRaWAN is the best candidate if your IoT application requires a network to work out of the grid, or in rural areas. LoRaWAN operates in an unlicensed band, has a long range (up to several kilometres), and consumes very little power – requiring batteries to last for multiple years.In addition, you can use private gateways for your device to provide access to the internet.

NB-IoT (Narrowband Internet of Things) is a licensed cellular technology that has been approved by 3GPP and utilizes existing LTE networks and licensed spectrum. With NB-IoT as an option, you have another viable method of connecting your devices to the Internet; how to do this depends on your needs. NB-IoT also has very good Quality of Service (QoS) because of its direct connection to either the Internet/cloud. While NB-IoT provides a reliable connection for several devices connected to the Internet, it can draw considerably more power than LoRaWAN and is therefore subject to some restrictions on carrier network connectivity.

Side by side LoRa module and NB-IOT module

Your best option for flexibility and extra low power consumption would be the LoRaWAN option, though if you need a mobile/cellular carrier level of reliable connectivity (with[during and after] supported network issues), then you would want to use NB-IoT instead.

To achieve 2-year battery life from one LiPo cell, you must practice aggressive power management. Start with a low consumption MCU and utilize deep sleep modes whenever possible, as many of the more modern MCUs will draw microamperes (µA) when idle. Use duty-cycling for everything, including the sensors, the radios, and even the regulators; they should turn on only when needed.

You can reduce the transmission time in all wireless communications (LoRa, WI-FI, BLE); wireless communications typically consume the largest amount of power. Make sure your firmware has been revised to allow for the controllers to be in sleep mode for an extended period of time in order to allow for quickly waking up, collecting data, transmitting data and returning to sleep mode. Additionally, reduce the quiescent current from your regulators and periphery.

The key to longevity is not purchasing a much larger battery; it is how much time the device spends in sleep mode.

The ESP32 is superior in the aspect of connectivity, with built-in Bluetooth and wi-fi. It is an exceptional device to use as a gateway for collecting, forwarding and transmitting information without having to use additional hardware. Additionally, the ESP32 has a large ecosystem, allowing for quick models to be deployed.

On the other hand, STM32 microcontrollers focus on reliability, low power, and deterministic performance; normally, they require additional RF Modules (LoRa, Sub-GHz). Depending on the use case, it will give greater real-time control to the gateway and industrial-grade reliability.

In conclusion, the ESP32 is an effective solution for fast, connected gateways, while the STM32 is an effective solution for a complete, robust, long-range unified solution by combining the best of both microcontrollers for efficient long-term operations.

Making clean Gerber files is the final stage between your design and a successful build. While there are different workflows with the use of the different tools used for generating Gerber files, the main fundamentals are always consistent - specifically for preparing files for JLCPCB.

First, go to KiCad. Then, Use the Plot menu. Typically, various layers must be output from the Plot menu in RS-274X format. You will not have a drill layer combined with your other layers when making the Gerber files. It’s extremely important that you process your drill layer independently of your other layers.

Once the Gerber files have been generated, you should also check the Gerber files for plotting accuracy using the internal viewer.

Gerber file preview / PCB layers visualization

In EAGLE, using a CAM Processor will allow users to load in a standard job Gerber file and generate all required layers. Be sure to double-check names when renaming layers to avoid any confusion.

Though EasyEDA does not create GERBERS by hand, users must still review output layers and preview before submitting order.

Gerber file preview / PCB layers visualization close-up

If using OrCAD, you will need to use the Manufacture → Artwork process. You will define the film output for the layers you require, as well as when you export to the NC drill files.

Regardless of the software you are using, there are three main steps that you will always need to do in order to prepare your final output – always include all of the layers required, always know what units you are using, and always verify the generated output prior to submitting it. A quick verification in a Gerber viewer may help prevent an expensive mistake in fabrication.

PCB with a green solder mask coating applied

PCBA shortages occur - good design planning can keep you moving forward. First, look for drop-in replacement parts - these should have the same packaging, pinout, and electrical specifications. If that's not possible, find functionally equivalent parts so that you can modify the design as early as possible. Use platforms like JLCPCB to see real-time availability of the component during your bill of materials (BOM) generation process.

Datasheet comparison is critical. If you want to avoid having to redesign your entire system at a later date simply because certain components are no longer available through the supply chain, putting enough design flexibility into your design early on will allow you to do so without any major inconvenience. Voltage tolerances, timing requirements, voltage ranges, and footprints must all be the same as specified in your specifications for the components used in your system.

The most important factors for any industrial air quality monitor are its accuracy and reproducibility. So I typically use JLCPCB since they combine PCB fabrication, SMT assembly and parts sourcing into one workflow to avoid handling errors and to maintain consistent builds across different batches.

For sensor-based designs, assembly quality has to be stable. Proper soldering, precise placement, and controlled process variables all contribute to retaining calibration and consistent performance over time. The availability of a large selection of components also makes it easier to source sensors, MCUs, and power components.

When combined with fast delivery times, this results in efficient iterations of products so they can be tested, adjusted and put into production.

Layout view of my PCB

Engineering a Robust Ecosystem

The heart of this system is the ESP32-WROOM-32U, providing the computational power and connectivity needed for real-time edge processing. By choosing JLCPCB, the transition from this complex, multi-layer design to a physical board was flawless, ensuring signal integrity for the high-sensitivity sensors integrated into the array.

Multi-Sensor Integration

To provide a comprehensive overview of environmental health, the board features a curated selection of industrial-grade sensors:

• MQ136 Gas Sensor: Specifically chosen for targeted gas detection (such as Hydrogen Sulfide), broadening the monitor's utility in specialized industrial zones.
• CCS811: For monitoring Total Volatile Organic Compounds (TVOCs) and equivalent CO2 levels.
• DFRobot SHT31-D: A high-precision digital temperature and humidity sensor protected by a PTFE membrane for long-term stability.

Power Management for the Field

Reliability in the field depends on power stability. The design incorporates a sophisticated power path:

• TP4056 Charging Module: Manages the 3.7V Li-ion battery lifecycle via USB.
• LM2596 Buck Converter: Ensures an efficient step-down to 3.3V/5V rails, maintaining steady operation even as battery levels fluctuate.

Multilayer PCB showing vias

Via stitching is a simple yet powerful way to improve your PCB design. Adding multiple ground vias along traces and adjacent to the edges will give you a low-impedance path between layers. This will help improve the flow of return current, reduce EMI, and help confine RF signals, especially for designs with high frequencies.

Stitched vias also aid in the thermal management of your board by creating a transfer path for heat generated by hot components to the internal planes of the PCB. They are typically used under power devices and next to ground planes.

The most important factor to consider when designing stitched vias is their spacing. You should have enough vias together to provide an effective low-impedance path (usually λ/10 at RF frequencies), but their total distance apart cannot be excessive.

With proper implementation, via stitching improves thermal performance as well as signal integrity.

I typically use four-layer PCB designs for high-speed digital logic designs, not for aesthetics, but to minimize problems down the road.

There are significant benefits to using four-layer PCBs, of which dedicated planes are the most obvious. A four-layer stack provides both a solid ground plane and a power plane, which significantly reduces noise and provides low-impedance return paths to the components in a circuit. The high-frequency returning paths will be through their signal traces as well as through the ground returning to it. Keeping this return path as continuous as possible using the ground plane keeps these paths very short, which will reduce the total size of the loop and therefore reduce the EMI generated.

4-layer PCB stackup diagram

The second benefit of using four-layer PCBs is signal integrity. With four-layer boards, the controlled layer spacing allows for better impedance control and reduced signal reflections. Signal integrity is important with very fast signal edges, even in “moderate” MHz designs, as rise time can create problems even at relatively low frequencies. In comparison to a simple two-layer board, where signals and return paths may compete for routing space, the four-layer PCB will have more consistent routing guidelines as well.

PCB internal layers / cross-section

In addition to using a consistent routing approach, the benefits of routing efficiency are significantly improved on a four-layer PCB due to having two outer signal layers and two inner planes available for routing. This substantially reduces the number of compromises such as reduced crossovers, long routing detours, or unwanted coupling between signals.

Last, but definitely not least, having a dedicated power plane significantly helps with power distribution. The dedicated power plane provides reduced voltage drop, and when placed close to the ground plane for decoupling, it creates a significant amount of inherent capacitance, which helps to stabilize the supply rails.

In the past, cost was an obstacle to using a 4-layer PCB, but now many manufacturers, particularly JLCPCB, are providing 4-layer PCBs at such low prices that the performance improvement almost rarely justifies the increased cost.

This creates cleaner signals, is less likely to cause EMI, and reduces the amount of time spent debugging the board.

Close-up of dense PCB traces

#ESP32# I started exploring **ESP-IDF** after spending about a year working with **Arduino IDE** and **Thonny**, and the shift in programming approach is honestly quite significant. With Arduino, functions like analogWrite() abstract away a lot of the lower-level details, which is great for rapid prototyping. But with ESP-IDF, you're working much closer to the hardware, writing more concise and explicit code that gives you finer control over peripherals.

Since it’s developed by Espressif Systems itself, the hardware integration feels far more robust. For example, instead of basic ADC reads, you get access to features like continuous ADC sampling, precise timing control, and dedicated calibration drivers—things that are either hidden or limited in higher-level environments.

Another major advantage is the built-in support for FreeRTOS, which opens up proper multitasking and real-time application development. Overall, it’s a powerful ecosystem worth exploring—especially if you’ve been considering moving beyond Arduino-level abstraction.

Stepper motors were one of those components I kept hearing about, especially in things like 3D printers and CNC machines—but I didn’t really understand why they were used everywhere until I actually started working with them.

The main reason is precision. Unlike regular DC motors that just keep spinning, stepper motors move in fixed steps. Most commonly, that’s 1.8° per step, which gives 200 steps for one full rotation. This makes them really useful when you need controlled movement without adding sensors.

Internally, a stepper motor has a rotor (the shaft) and a stator with coils arranged in phases (usually A and B). By energizing these coils in a specific sequence, a rotating magnetic field is created, and the rotor keeps aligning with it. Instead of continuous rotation, it moves step by step.

One thing I initially misunderstood was microstepping. I thought it just increases the number of steps and gives more accuracy—but it’s a bit more nuanced than that.

With microstepping, instead of fully energizing one coil at a time, the driver controls current in both coils in ratios (like 50/50 or 75/25). This lets the rotor settle between full steps, making motion smoother and reducing vibrations. But it doesn’t necessarily mean you’re getting perfectly accurate “extra steps”—torque per microstep is lower, and there are nonlinearities.

Another thing that confused me early on was NEMA ratings. NEMA 17, NEMA 23, etc., don’t define performance—they only specify the physical size of the motor faceplate. Torque and current ratings can vary a lot even within the same NEMA size.

Drivers are also a big part of the system. Stepper motors aren’t just voltage-driven—you need drivers that regulate current properly. That’s where modules like A4988, DRV8825, and TMC2209 come in. Choosing the right one depends mainly on the current your motor needs and how smooth you want the motion.

Here are some common driver options and where they fit:

stepper gif from https://www.wikipedia.org/

#electronics# #robotics# #steppermotor# #embedded# #engineering#

Hey there! if you’ve ever wanted to dive into the world of power electronics but felt intimidated by all the math and tiny components, this post is for you. In this post you will see how to build a high-efficiency buck converter, the magic device that takes a higher voltage (like from a battery) and steps it down to a lower voltage (like for your microcontrollers) without wasting a ton of energy as heat.

let’s break down how to design and build one of these as a beginner.

Why a buck converter? Well, linear regulators are easy, but they’re basically just fancy resistors that get hot. a buck converter uses an inductor and high-speed switching to be way more efficient. think of it like a dimmer switch for your power.

What you'll need (the bill of materials):

• the controller: mc1068c buck regulator ic.
• the inductor: 0.47μh (i used the mpl-al4020-r47 for its solid 12.5a saturation current).
• resistors:
  • r1: 100kOhm
  • r2: 49.9kOhm (these set your output voltage via the feedback pin).
• capacitors:
  • input: c1a, c2 (ceramic, 10μf to 22μf range).
  • output: c21, c22, c23 (we use multiple in parallel to keep the voltage smooth).
  • feed-forward: cff (a tiny 10pf cap to help with stability).
• connectors: standard screw terminals or headers for vin and vout.

Layout tips

when you look at my PCB layout, you'll notice a few things:

• keep it tight: the input capacitors (decoupling) and the inductor need to be as close to the ic as possible. this minimizes ringing and noise.

• big copper: notice the thick traces? high current needs space to move, or your board will act like a heater.

• ground plane: use a solid ground pour on the bottom layer. it acts as a shield and a heat sink.

  The layout is a begginer one! it has a lot of room for improving, what would you change?

Final thoughts

building your own power supply is a rite of passage. it feels pretty great when you plug in 5v, and a rock-solid 1.2v comes out the other side without a puff of smoke. Obviously the PCB layout is just a beginner project to get started with PCB design!

#POWERELECTRONICS# #PCB# #PCB# #JLCPCB#