Home M5Stack Chain Mechanical Key Button (STM32G031)

M5Stack Chain Mechanical Key Button (STM32G031)

SKU: M5-U206
Sale price 10,34 €
incl. VAT
excl. VAT
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M5Stack Chain Mechanical Key Button (STM32G031)

M5Stack Chain Mechanical Key Button (STM32G031)

10,34 €

Description

Chain Key is a single-button input node in the M5Stack Chain series. It combines a hot-swappable mechanical blue switch, programmable RGB feedback and an STM32G031G8U6 core MCU in a compact Chain-series control module.

Chain Key uses UART serial cascading communication, making it suitable for interactive button controls, smart home actions and human-machine interfaces. With two HY2.0-4P expansion interfaces, Chain Key can be connected with more Chain series devices to build larger interactive systems.

Features

  • Single-button Chain input: Chain Key provides one tactile button node for M5Stack Chain-series projects.
  • Hot-swappable blue switch: the mechanical keyboard switch design gives Chain Key clear tactile feedback and easy switch replacement.
  • STM32G031G8U6 MCU: an integrated STM32G031G8U6 controller handles key input, RGB output and Chain communication.
  • Programmable RGB feedback: two WS2812C RGB LEDs let Chain Key show status, alerts and interactive lighting effects.
  • UART cascading protocol: Chain Key communicates through UART at 115200bps@8N1 for Chain-series expansion.
  • Dual HY2.0-4P connectors: two expansion interfaces help connect Chain Key with Chain Bridge, Chain DualKey and other Chain devices.
  • Compact control node: the 23.9 x 23.9 x 34.4mm body fits small smart home panels, control boxes and desktop interaction projects.

Specifications

MCU STM32G031G8U6
Input Power DC 5V
Communication Method UART 115200bps@8N1
Interface Spec 2 x HY2.0-4P
RGB LED 2 x WS2812C
Working Power Consumption 28.24mA
Working Temperature 0 ~ 40°C
Product Size 23.9 x 23.9 x 34.4mm
Product Weight 9.1g
Package Size 138.0 x 93.0 x 26.0mm
Gross Weight 14.4g

Applications

  • Smart home scene triggers and programmable wall-button projects using Chain Key.
  • Human-machine interaction panels that need tactile input plus RGB status feedback.
  • Desktop control buttons, macro controls and quick-action input devices.
  • Chain-series interactive installations with multiple cascaded input modules.
  • Education and prototyping projects that demonstrate UART cascading and button-event handling.

Product List

  • 1 x Chain Key
  • 1 x Chain Bridge
  • 1 x Keycap Sticker

Other Content

Chain Connection Direction

When using the Chain Bridge connector, connect the main controller Chain DualKey with Chain Key and other Chain series input devices in the correct direction. The triangle arrow should point outward from the Chain DualKey controller.

Communication And Expansion

Chain Interface Two HY2.0-4P connectors provide input and output chaining for Chain Key.
Serial Settings UART communication uses 115200bps@8N1.
Controller Pairing Use Chain Bridge with Chain DualKey to connect Chain Key into a Chain-series setup.
Development Resources Arduino quick start, M5Chain library, example program, UiFlow2 documentation, firmware and protocol files are listed in Resources.

Resources

FAQ

What is Chain Key used for?

Chain Key is used as a single-button input node for smart home control, human-machine interaction, quick-action controls and Chain-series interactive projects.

Which controller does Chain Key use?

Chain Key integrates an STM32G031G8U6 MCU for button input, RGB LED control and UART Chain communication.

How does Chain Key communicate?

Chain Key uses UART serial cascading communication at 115200bps@8N1.

Can Chain Key connect with other Chain devices?

Yes. Chain Key has two HY2.0-4P expansion interfaces and can be connected with Chain Bridge, Chain DualKey and other Chain series devices.

What is included in the package?

The package includes 1 x Chain Key, 1 x Chain Bridge and 1 x Keycap Sticker.

1. General Shipping Information

  • We provide reliable shipping services with a tracking number for each order.
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  • Please make sure your shipping address is accurate before placing your order. We ship strictly according to the address provided at checkout.
  • In-stock orders are usually dispatched within 1 business day after order confirmation.
  • Estimated delivery times refer to the period after dispatch and do not include order processing time, weekends, public holidays, customs inspection, or force majeure delays.
  • If you need to cancel or modify your order, please contact us before the order is marked as “Shipped”. Once shipped, the order cannot be canceled or changed.

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2. Shipping Rates & Options

Shipping rates are calculated based on order value, destination, and available shipping methods. The final available options will be displayed at checkout.

2.1 Germany Domestic Shipping

Shipping Method Order Value Cost Est. Delivery
Deutsche Post €0.00 - €50.00 €4.95 2-4 Business Days
Deutsche Post Over €50.00 Free 2-4 Business Days
DHL Paket
(Faster Delivery)
€0.00 - €50.00 €6.95 1-3 Business Days
DHL Paket
(Faster Delivery)
€50.00 - €100.00 €2.00 1-3 Business Days
DHL Paket
(Faster Delivery)
Over €100.00 Free 1-3 Business Days

2.2 Selected EU Countries / Regions

Available EU shipping destinations are shown at checkout based on your shipping address. For orders shipped to selected EU countries or regions outside Germany, we use FedEx Regional Economy.

Shipping Method Order Value Cost Est. Delivery
FedEx Regional Economy €0.00 - €100.00 €7.95 3-5 Business Days
FedEx Regional Economy Over €100.00 Free 3-5 Business Days

EU orders may be fulfilled from our Munich warehouse or, when applicable, from our Shenzhen warehouse depending on inventory availability. For EU member states, OpenELAB covers applicable import duties and taxes under DDP service where required.

2.3 United States

Region Shipping Method Order Value Cost Est. Delivery
Continental U.S.
(50 States)
USPS Ground Advantage €0.00 - €45.00 €4.95 3-7 Business Days
USPS Ground Advantage Over €45.00 Free 3-7 Business Days
USPS Priority Mail €0.00 - €45.00 €16.95 1-4 Business Days
USPS Priority Mail Over €45.00 €14.95 1-4 Business Days
Non-Continental U.S.
(AK, HI, PR, etc.)
USPS Ground Advantage €0.00 - €60.00 €6.95 5-9 Business Days
USPS Ground Advantage Over €60.00 Free 5-9 Business Days

Non-Continental U.S. regions include Alaska, American Samoa, Guam, Hawaii, the Marshall Islands, the Northern Mariana Islands, Palau, Puerto Rico, the U.S. Virgin Islands, and U.S. Armed Forces addresses.

2.4 International Destinations Outside the EU

For selected international destinations outside the EU, including Switzerland, the United Kingdom, and Norway, shipping rates are as follows:

Order Amount Shipping Cost
€0.00 - €300.00 €19.95
Over €300.00 Free

For non-EU destinations, import duties, taxes, and customs fees may be charged by the destination country and are the responsibility of the recipient.

3. Warehouses & Fulfillment

Our products may be stored in our Munich, Arlington, and Shenzhen warehouses. The actual shipping warehouse depends on product availability and destination.

3.1 Munich Warehouse

For products stored in our Munich warehouse, we use Deutsche Post or DHL Paket for domestic deliveries within Germany. For selected EU destinations outside Germany, we use FedEx Regional Economy.

3.2 Arlington Warehouse

For products stored in our Arlington warehouse, we use USPS or UPS for deliveries within the United States.

3.3 Shenzhen Warehouse

For pre-order items or products fulfilled directly from our Shenzhen warehouse, we arrange reliable international shipping based on destination and inventory status. For EU member states, OpenELAB covers applicable import duties and taxes under DDP service where required.

4. Inventory, Pre-orders & Split Shipments

  • Inventory Status: Please check the product page for real-time stock information. If an item is out of stock in our local warehouses, it may be marked as “Pre-order”.
  • Pre-order Fulfillment: Pre-order items may be shipped directly from Shenzhen or restocked to a local warehouse first before final delivery.
  • Split Shipments: If your order contains both in-stock and pre-order items, we may ship them separately. No additional shipping fee will be charged for split shipments caused by our fulfillment arrangement.

5. Customs, Taxes & Delivery Issues

5.1 Customs and Taxes

For EU Member States:
Whether shipped from Germany or China, OpenELAB covers applicable import duties and taxes under DDP service where required. Customers in EU member states should not be charged additional import duties or VAT upon delivery.

Important Notice for Non-EU Countries:
For destinations outside the European Union, such as Switzerland, Norway, and the United Kingdom, import duties, taxes, and customs fees may be charged by local authorities upon delivery. These fees are the responsibility of the recipient.

5.2 Damaged, Delayed, or Lost Parcels

Please inspect your parcel upon delivery where possible. If you notice visible damage, please report it to the courier and contact us as soon as possible. This does not affect your statutory consumer rights.

If your parcel is delayed, lost, returned to sender, or the tracking information has not updated for an unusual period of time, please contact us at info@upenelab.com. We will assist you in checking the shipment status with the courier.

5.3 Incorrect Address or Failed Delivery

If a parcel cannot be delivered due to an incorrect or incomplete address provided by the customer, refusal of delivery, or failure to collect the parcel, additional shipping or return costs may apply.

6. VAT

For orders within the EU, VAT is collected at checkout according to the applicable destination rules. No additional VAT should be collected upon delivery for EU member state orders covered under our DDP shipping arrangement.

Customer Reviews

Based on 3 reviews
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Dakota Hughes
M5Stack Chain Mechanical Key Button (STM32G031): smooth first setup

I added M5Stack Chain Mechanical Key Button (STM32G031) to a recent project and found the initial setup straightforward. It has remained dependable and delivered the result I expected.

K
Kendall Price
M5Stack Chain Mechanical Key Button (STM32G031): useful after setup

After working with M5Stack Chain Mechanical Key Button (STM32G031) for a while the overall experience felt stable and predictable. The result was good after a little adjustment during the first configuration.

S
Sydney Bell
M5Stack Chain Mechanical Key Button (STM32G031): solid build quality

The M5Stack Chain Mechanical Key Button (STM32G031) arrived in good condition and fitted neatly into my existing setup. Integration went smoothly and I have not encountered any significant issues.