Cheap electronics modules from China: clones explained

Most cheap electronics modules from China are not fakes in any useful sense. They are generic boards built around a documented design, often with a different USB chip or a second-source microcontroller, and they work. A smaller group is something else: a part sold under a name or model it is not, such as a BMP280 listed as a BME280, or a board printed with a trademark it has no right to. This article explains where that line sits, which substitutions are common, how to check what arrived, and when it is worth paying for the genuine part.

Cheap electronics modules from China: three different things

These words get used loosely, and the differences matter.

A compatible board copies a published, open design and sells under its own name. Arduino publishes most of its hardware designs as open source, so copying the design is allowed. Arduino's trademark guide for compatible products says a copied product still cannot be called "Arduino" and should carry its own brand, though it may describe itself with phrases such as "compatible with Arduino". Arduino's own support pages treat compatible boards as no problem.

A clone is the colloquial word for the same thing, often a board that copies the layout of a well-known one (a Nano-shaped board with an ATmega328P, say) under a generic name or none at all. Clones are legal in the same way compatibles are, as long as they do not borrow the brand.

A counterfeit uses the brand or marking it is not entitled to. A board with the Arduino logo and name on it that did not come from Arduino is not legitimate, however well it works. The same goes for a chip whose top marking has been changed to read as another manufacturer's part.

The first two are a normal part of the maker world. The third is a problem because you are being told something false, and you cannot know what else was cut. If you want a genuine board, buy from the manufacturer or an authorised reseller. If you want a cheap generic one, buy it as a generic one.

The common substitutions

Most differences between a cheap module and its better-known equivalent come down to a short list.

CH340 instead of FTDI or ATmega16U2

Arduino Uno R3 boards use an ATmega16U2 as the USB-to-serial bridge. Older boards and many third-party boards used FTDI chips. Cheap Nano and Uno-style clones very often use a WCH CH340 instead. It is a cheaper chip that does the same job: it turns USB into a serial port that the main microcontroller talks to.

The practical consequences are small but real:

• Drivers. On Linux, the CH340/CH341 driver is included in the kernel of most current distributions, so the board usually shows up as /dev/ttyUSB0 with nothing to install. On Windows and macOS you may need WCH's driver. Sources disagree on whether current versions install it automatically, so plug the board in first and see whether a new serial port appears before downloading anything. On macOS you may have to approve the driver in System Settings after installing.
• No native USB. The ATmega16U2 on an official Uno can be reprogrammed to act as a keyboard or other USB device. A CH340 cannot. If your project needs the board to appear as a keyboard or MIDI device, you want a microcontroller with native USB, not a CH340 board.
• Reliability is mostly fine. The CH340 is a widely used, documented chip. It is not a defect that a clone has one. If a CH340 board fails to upload, a bad cable (charge-only) or a missing driver is far more likely than the chip.

A footnote: in 2014 FTDI released a Windows driver update that reportedly stopped counterfeit FTDI chips from working, which is part of why many cheap boards moved to CH340 and similar chips. If a board claims an FTDI chip, check that it is one.

Alternative microcontrollers: LGT8F328P and STM32 second sources

Some boards that look like an Arduino Nano or Pro Mini use a different microcontroller entirely.

The LGT8F328P, from Logic Green, is a chip designed to be close to the ATmega328P. Sources describe it as running at 32 MHz, twice the usual clock, and as largely but not fully compatible. It has features the ATmega328P does not have, and some it does differently: its EEPROM is emulated in flash, for instance, and the original datasheet is in Chinese with English translations from third parties. It needs its own board support package in the Arduino IDE. Code that pokes at registers, timers or the ADC directly may behave differently from the same code on a real ATmega328P. A listing that says "ATmega328P" and ships an LGT8F328P is a mislabelled product, not a compatible one. A listing that says LGT8F328P openly and ships one is simply a different board.

On the ARM side, the "Blue Pill" style boards sold as STM32F103 are the well-known example. GD32F103 from GigaDevice is a documented second source for the STM32F103: same package and largely the same pinout and registers, so existing code often runs. It also differs. The core can run faster, and flash timing and wait states differ from the STM32, so clock and flash settings copied from STM32 code need rechecking. Low-power behaviour is not the same either, and distributor comparison tables disagree on details, so check GigaDevice's datasheet against yours before relying on a particular figure.

CKS32 is a different story. China Key System & Integrated Circuit makes a separate part under that name, and researchers have found STM32F1-marked chips that turned out to be CKS-made on inspection. Forum posts speculate about how these relate to GD32; we found no authoritative confirmation, so treat that as unknown. A board honestly sold as GD32 or CKS32 may work for your project. A chip marked STM32 with different silicon underneath means you were not told the truth.

BME280 and BMP280

This is the mix-up makers hit most often, because the boards look nearly identical and the names differ by one letter.

Both are Bosch environmental sensors in a small metal-lid package. The BME280 measures temperature, pressure and humidity. The BMP280 measures temperature and pressure only. If your weather station needs humidity, a BMP280 will give you temperature and pressure readings and nothing for humidity, and some libraries will print a humidity value of zero or an error.

A seller who labels a BMP280 board "BME280" may be careless or may be hoping you will not notice. Either way you get a product that cannot do the job. Colour is not a reliable guide: board colour and silkscreen are the module maker's choice, not Bosch's. Check the chip itself.

Remarked and recycled chips

Remarked chips have had their surface sanded or coated and new markings printed, usually to pass a cheaper part off as a dearer one. Recycled chips are pulled from scrap boards and sold as new. Both exist in the wider supply chain, but they are a bigger risk with loose ICs from unknown sources than with finished modules built from reeled stock. Warning signs are uneven or ghosted printing, inconsistent pin 1 dots, scratches on the surface, and pins that look used.

Lower-spec passives

The least visible difference is in resistors, capacitors and regulators. A cheap module may use a looser-tolerance capacitor, a part with a lower voltage rating, or a basic linear regulator with less current headroom than the reference design. For most hobby circuits this does not matter. It matters when a module runs near its limits, such as a regulator feeding a Wi-Fi board with current spikes. A high current figure in a listing is a seller claim, not a measurement.

How to spot what you got

Read the chip

Look at the markings with a loupe or a phone camera in macro mode. Check three things: that the part number matches what you ordered, that the print is crisp and even, and that the package and pin count match the datasheet. An ATmega328P has a specific layout and marking; a board claiming it but showing a different, unfamiliar logo is telling you something.

A marking is only what is printed on top. It is a clue, not proof, so pair it with a functional check where one exists.

Ask the chip who it is

For many digital sensors, the chip answers a question about itself. This is the cleanest test there is.

For the BME280 and BMP280, the identity register sits at address 0xD0. A BME280 returns 0x60. A production BMP280 returns 0x58. Bosch documented earlier BMP280 sample parts with other values, so 0x56 or 0x57 points to early samples, not a BME280. A short I2C scanner sketch plus a read of that register tells you which part you have, regardless of what the silkscreen says. The values are listed in the Bosch datasheets for each sensor.

Many sensor libraries already do this. If one reports no BME280 but a scan shows a different ID, you probably got the wrong part. Microcontrollers have similar reads, such as the STM32 device ID or AVR signature bytes. Forum threads report that several fake STM32s return the wrong JTAG ID, which is how they get caught.

Use QC photos

If you buy through a shopping agent, the warehouse photos are your last chance to catch a wrong part before it crosses a border. Ask for the specific shot that answers your question: the top of the sensor chip, the USB chip on a Nano clone, or the header and silkscreen. A photo of a plastic bag does not tell you anything.

Check the photo against the variant you ordered. The choosing the right variant guide covers how listings bundle several versions, and the how to buy from 1688 guide covers the ordering side. Free photos help, but a paid close-up of the right corner of the board usually beats a free picture of the whole parcel.

Tip: order one before you order five, check it, then reorder. A second small parcel costs less than five wrong sensors.

Test it, not just inspect it

Power the module from a bench supply or a USB meter and watch the current. Run a basic example sketch and read the sensor for a few minutes. A temperature reading ten degrees off in a room is a bad unit or a different part. For modules with a regulator, check the output voltage unloaded and under a realistic load.

When clones are fine, and when to buy genuine

Genuine is not automatically better. It depends on what the part is doing.

Clones are fine for learning, prototyping, anything easy to replace, and boards built to an open reference design such as a plain Nano-style board or a common ESP32 development board. They suit parts whose identity you can verify yourself, like a sensor you can read back over I2C, and bulk jobs where one failed board costs minutes.

Buy genuine, or at least from a known source, where the stakes rise:

• Mains, chargers and lithium cells. A lower-spec protection component is not a place to economise, and battery failure is a heat problem, not a bad reading.
• Precision measurement. If you need datasheet accuracy, an unverified chip with unknown calibration may not deliver it.
• Products you sell. Shipping clone chips in a product raises licensing, trademark and support questions a hobby project does not.
• Projects that depend on specific behaviour. Native USB, exact timing, sleep current, or a vendor library.

If you want genuine, a vague listing at a suspiciously low price with a famous name on it is information, and usually not good information.

What PartLark claims and does not claim

PartLark is a catalogue of maker parts matched to Chinese marketplace listings. Matching is based on functional fit, not brand identity. A listing counts as a match when it is honestly a generic part and the core function, chip family and relevant electrical and mechanical requirements match. A branded alternative is accepted only when the listing actually claims that brand and the evidence supports it. Brand names are never inferred from how a board looks.

Some distinctions are kept sharp on purpose. A different sensor is not a match, so a BMP280 is not a BME280. A generic Zero-style board is not a Pico, and a SuperMini is not a genuine XIAO. PartLark does not call a listing genuine, original, tested or quality-checked unless the evidence establishes it, because seller slogans are claims, not proof. Generic and clone parts are labelled as such.

Matches are automatic and can be wrong. They are a sourcing aid, not a guarantee of fitness, safety or authenticity, so read the listing, check the chip, and use QC photos where the exact part matters.

FAQ

Is it legal to buy Arduino clones?

Arduino publishes most of its hardware designs as open source, and says compatible boards that copy the design under their own brand are no problem. What is not allowed is selling a board under the Arduino name or logo when it did not come from Arduino. Rules differ by country, so if you resell boards, get local advice.

Do I need a driver for a CH340 board?

Often not on Linux. On Windows and macOS it depends on your version, so plug the board in and see whether a serial port appears. If not, WCH publishes an installer for the CH340/CH341 family. If uploads fail, try another cable first, since charge-only cables are a common cause.

How can I tell a BME280 from a BMP280?

Read the chip ID at register 0xD0 over I2C: 0x60 for a BME280, 0x58 for a production BMP280. A missing or zero humidity reading is the other giveaway.

Does a cheaper chip mean a worse board?

Not by itself. A CH340 instead of an ATmega16U2, or a GD32 instead of an STM32, can work perfectly. The trouble starts when the listing hides the substitution, or when your code assumes the original chip's behaviour.

Next steps

If you want to see how this plays out for a specific part, browse the catalogue, compare the matched listings and variants, and check the chip named in each. Add what you want to your haul to see the goods subtotal, remembering that domestic freight, agent fees, shipping and import charges come on top; what landed cost really includes walks through the arithmetic. Why PartLark and how it works explain what the site does and does not claim. Some Superbuy links on PartLark are affiliate links, and the catalogue is the same whichever way you buy.