Home Raindrop Sensor | LM393 Analog & Digital Output
Raindrop Sensor - OpenELAB
Raindrop Sensor - OpenELAB
Raindrop Sensor - OpenELAB
Raindrop Sensor - OpenELAB

Raindrop Sensor | LM393 Analog & Digital Output

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SKU: HS-S09A-B
Sale price 3,57 €
incl. VAT
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Guarantee & Return Policy

For purchases of goods from OpenELAB Technology Ltd. through upenelab.com. OpenELAB Technology Ltd. is a company based in Shenzhen, China. This page explains withdrawal rights, statutory rights relating to defective goods, additional warranties and return procedures. The contractual basis is set out in our Terms and Conditions.

Effective date: September 30, 2026 Terms and Conditions

1. Consumer Right of Withdrawal

This section applies to consumers who purchase goods by distance selling where a statutory right of withdrawal applies under mandatory consumer protection law. For consumers in Germany and other EU jurisdictions, applicable mandatory consumer protection rules remain unaffected.

Right of Withdrawal

Where the statutory 14-day withdrawal right applies, you have the right to withdraw from the contract within fourteen days without giving any reason.

The withdrawal period is fourteen days from the day on which you, or a third party designated by you who is not the carrier, takes physical possession of the goods. If several goods forming part of one order are delivered separately, the period begins when the last item is received. If a single product is delivered in several consignments or parts, the period begins when the final consignment or part is received.

To exercise your right of withdrawal, you must inform us of your decision by means of a clear statement, for example by email or letter:

OpenELAB Technology Ltd.
Parkring 5, 4. OG., 
85748 Garching bei München, Germany
Email: info@upenelab.com
Telephone: +49 155 61896199

You may use the model withdrawal form provided in Section 3 below, but use of the form is not mandatory.

If an online withdrawal form is made available on this page, you may also submit your withdrawal through that form. After submission, we will send confirmation of receipt on a durable medium, such as by email, including the content of your withdrawal declaration and the date and time it was received.

To meet the withdrawal deadline, it is sufficient for you to send your communication concerning the exercise of the right of withdrawal before the withdrawal period expires.

Effects of Withdrawal

If you validly withdraw from the contract under an applicable statutory right of withdrawal, we will reimburse all payments received from you, including standard delivery costs. Additional costs resulting from your choice of a delivery method other than the least expensive standard delivery method offered by us do not have to be reimbursed where permitted by applicable law.

Reimbursement will be made without undue delay and, where the applicable law provides for a fourteen-day reimbursement period, no later than fourteen days from the date on which we receive your withdrawal notice.

Unless otherwise expressly agreed, reimbursement will be made using the same payment method that you used for the original transaction. You will not be charged any fee by us for the reimbursement.

Where permitted by applicable law, we may withhold reimbursement until we have received the goods back or you have supplied evidence of having sent the goods back, whichever occurs first. This does not apply where we have offered to collect the goods.

You must return or hand over the goods without undue delay and, where the applicable statutory rules provide for a fourteen-day return period, no later than fourteen days after informing us of your withdrawal.

Returns should be sent to our authorized return facility in Germany, unless we provide different return instructions for the specific product or case.

You bear the direct cost of returning goods where this is permitted by applicable law and where the goods can normally be returned by parcel service. For goods that cannot normally be returned by parcel service, return arrangements and costs will be handled in accordance with the applicable mandatory consumer protection rules.

You are responsible for any diminished value of the goods only where and to the extent that such diminished value results from handling beyond what is necessary to establish the nature, characteristics and functioning of the goods, subject to applicable law.

2. Exceptions and Additional Information

Statutory withdrawal rights may be excluded in certain cases provided by applicable consumer law. This may include goods that are not prefabricated and are made according to an individual choice or specification of the consumer, or goods that are clearly personalized.

For consumers in Germany, this includes the exception under Section 312g (2) No. 1 of the German Civil Code (BGB). A normal pre-order or procurement of a standard product specifically for a customer's order does not, by itself, make the product customized.

Statutory exceptions may also apply to sealed audio or video recordings or computer software where the seal has been removed after delivery. Ordinary hardware does not become excluded from withdrawal merely because normal product packaging, protective packaging or antistatic packaging has been opened.

Where a relevant statutory exception applies, the customer will be informed as required before the contract is concluded.

An existing statutory right of withdrawal may generally be exercised before the goods are received. Procurement or dispatch of the goods does not by itself eliminate the withdrawal right.

A return request or RMA authorization is not a condition for the valid exercise of a statutory withdrawal right. However, simply refusing delivery or returning goods without any accompanying statement may not reliably constitute a clear withdrawal declaration.

No blanket handling fee, restocking fee or payment-provider fee will be charged solely because a consumer exercises a statutory withdrawal right. Opening, powering on, programming or the absence of the original packaging does not automatically justify a deduction.

Any deduction for diminished value will only be made where permitted under the applicable mandatory law and where the legal requirements for such a deduction are met.

Separately commissioned paid repairs, training services or standalone digital services may be subject to separate withdrawal information. Where required, the relevant withdrawal information will be provided before the respective contract is concluded. This goods return policy does not replace those separate notices.

3. Model Withdrawal Form

If you wish to withdraw from the contract, you may complete and return this form. Use of this form is optional. A clear statement of withdrawal is sufficient, and you are not required to provide a reason.

To:
OpenELAB Technology Ltd.
Parkring 5, 4. OG., 
85748 Garching bei München, Germany
Email: info@upenelab.com

I/We (*) hereby give notice that I/We (*) withdraw from my/our (*) contract of sale of the following goods (*) / for the provision of the following service (*):

Information Details
Goods / quantity or service  
Ordered on (*) / received on (*)  
Name of consumer(s)  
Address of consumer(s)  
Signature of consumer(s) (only if submitted on paper)  
Date  

(*) Delete as appropriate.

You may voluntarily include your order number to help us identify the order. A withdrawal declaration does not have to be made using this form.

4. Statutory Rights for Defective Goods

If a product is defective, incorrectly supplied or does not have agreed characteristics, please contact OpenELAB. Your statutory claims are against OpenELAB Technology Ltd. as the seller. Manufacturer approval is not an additional condition for exercising statutory rights against us where such rights apply.

Consumers may exercise statutory rights relating to defective goods without being charged for remedies where this is required by applicable mandatory consumer law. Necessary shipping, transport, labor and material costs, as well as legally covered removal and reinstallation costs, will be handled in accordance with applicable law.

Where return of a defective product is necessary, we will provide an appropriate prepaid shipping method or agree the applicable shipping arrangements where required by law.

Statutory choices between repair and replacement remain available within the limits established by applicable law. Additional rights, including price reduction, termination of the contract and damages, are subject to the applicable legal requirements.

A fourteen-day withdrawal period is not a deadline for reporting product defects. For business-to-business transactions, statutory inspection and notification obligations applicable to the relevant contract remain unaffected. Where German commercial law applies, this includes Section 377 of the German Commercial Code (HGB).

Intended programming, permitted firmware flashing, intended soldering or normal integration of development products does not automatically eliminate statutory rights relating to defects. The specific defect and its cause are decisive.

Batteries, cables and wear parts are likewise not automatically excluded from statutory defect rights. Normal wear and tear must be distinguished from a legally relevant defect.

5. Additional Warranties

A manufacturer's warranty is provided by the respective manufacturer. Any additional OpenELAB commercial warranty is provided by OpenELAB Technology Ltd., Shenzhen, China.

Whether a commercial warranty is provided, and its duration, coverage, included parts, usage limitations and geographical scope, is determined by the applicable warranty statement or a binding product-specific commitment.

Any commercial warranty is additional to, and does not restrict, statutory consumer rights that apply under mandatory law.

This general page does not create a new uniform commercial warranty for all products. Existing binding warranty commitments, including previously issued OpenELAB warranty commitments, remain valid according to their respective terms.

Where required by applicable consumer law, the relevant commercial warranty statement will identify the warranty provider, contact details, covered goods, warranty conditions and claim procedure and will be provided on a durable medium within the legally required timeframe.

6. Business Customers: Changes and Voluntary Returns

Business customers do not receive a consumer right of withdrawal solely because an order was placed online or at a distance.

Voluntary cancellations, product changes or returns of conforming and non-defective business orders are handled in accordance with the applicable Terms and Conditions and any individual agreement between the parties, including any agreed costs.

The forms provided on this page do not create an additional B2B return right. Statutory or contractual rights relating to defects, delay, non-performance or other legal grounds remain unaffected.

7. Returns and Claims in Practice

When reporting a product issue, please provide your order or invoice reference, the affected product and a reasonably detailed description of the issue. Software versions, photographs or logs may help us investigate the case where they are reasonably available and relevant.

Alternative proof of purchase may also be reviewed. For a statutory withdrawal, you do not need to provide a defect description, photographs or technical evidence.

You may use our return form or contact us directly to coordinate return logistics. We will provide the appropriate shipping instructions and, where applicable, an RMA number.

An RMA number is an administrative and logistics tool and is not an authorization requirement for exercising statutory rights. Do not delay a legally time-sensitive withdrawal declaration while waiting for an RMA response.

Authorized Return Address in Germany

OpenELAB GmbH
Parkring 5, 4. OG.,
85748 Garching bei München
Germany

This German address is an authorized return and logistics facility for OpenELAB returns. The seller and contracting party for purchases covered by this policy is OpenELAB Technology Ltd., Room 1511, Fuchun Oriental Building, Futian District, Shenzhen, China .

The use of the German return facility does not change the identity of the seller or contracting party.

Please use the return address communicated for your specific return. For ordinary returns, prior RMA authorization is not a condition for exercising statutory rights, although contacting us before shipment helps ensure that the goods are routed to the correct facility.

For an agreed collection or specialized repair, please follow the shipping instructions provided for that case. The seller's business address in China is not automatically the correct physical return location for products, heavy equipment or batteries.

Pack products securely for transport. Sensitive electronics should be protected with appropriate ESD packaging where reasonably necessary. Accessories that form part of the return should also be included.

Original packaging is helpful but is not, by itself, a condition for exercising statutory consumer rights. Please retain proof of shipment.

Where we provide a return label or agree a specific shipping method, please use the provided method where reasonably possible. No blanket penalty fee is imposed merely because a different shipping method is used, although additional avoidable costs may be handled in accordance with applicable law or an individual agreement.

For heavy products, freight shipments, or damaged or potentially unsafe batteries, please contact us so that an appropriate collection or safe transportation method can be arranged. Damaged or unsafe batteries must not be sent through ordinary parcel services where transport regulations prohibit or restrict such shipment.

These safety and logistics arrangements do not shorten statutory deadlines or rights.

Where reasonably possible, back up your own data and remove personal credentials or access information before returning a device. If this is not possible because of the defect, please inform us.

This does not exclude or limit liability that cannot legally be excluded. Necessary service-related personal data is processed in accordance with our applicable Privacy Policy.

Paid inspections or repairs outside an existing statutory, contractual or warranty entitlement will only be carried out after we inform you of the scope of work and the applicable price or pricing basis and you authorize the service.

The same applies to agreed inspection or return shipping costs following rejection of a repair quotation. A fault that cannot initially be reproduced does not automatically result in a service fee.

8. Return Form and Contact

The return form may be used for product claims, return logistics and requests for voluntary returns.

To clearly exercise a statutory consumer withdrawal right, use the withdrawal form provided on this page or send another clear statement informing us of your decision to withdraw. Selecting a technical return reason alone does not determine your statutory rights.

Start a return / manage your order

Sign in using your order email address and the code sent to your inbox. Open your order, select the item(s) and quantity you wish to return, then submit your request. We review requests under the conditions on this page and any applicable individual agreement. Submitting a request does not mean a refund has been approved.

Warranty or other assistance

If no return option is available, you cannot sign in, or you need help with a product fault, warranty, repair or exchange, email info@upenelab.com. Include your order number if available, the product, quantity and your request. Photos or videos may help with product faults. You can still contact us about applicable defect rights or warranty coverage after a standard return window has ended. The conditions on this page and any applicable individual agreement apply.

Consumer withdrawal by email

Where a statutory consumer withdrawal right applies, you may send a clear declaration to info@upenelab.com. No reason or approval from our customer service team is required to exercise that right.

Prepare a withdrawal email

This link opens a draft in your email app. Complete and review the details, then send the email yourself. Opening the draft does not submit a declaration. If no email app opens, copy the address above and email us directly.

OpenELAB Technology Ltd.
Parkring 5, 4. OG.

85748 Garching bei München
Email: info@upenelab.com  ·  Telephone: +49 155 61896199
Website: upenelab.com
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Raindrop Sensor - OpenELAB

Raindrop Sensor | LM393 Analog & Digital Output

3,57 €

Raindrop Sensor Module with LM393 Analog and Digital Outputs

The Raindrop Sensor detects water droplets on a large plated sensing board and provides both analog and digital outputs. It is suitable for rain alarms, automatic window or sunroof projects, smart lighting triggers, and weather-station prototypes.

The module uses an LM393-style comparator for the digital threshold output and also exposes an analog voltage for estimating droplet coverage. For comparator background, see the TI LM393 product page; for Arduino wiring, it pairs well with an OpenELAB Sensor Shield V5.

The detection board is made for contact with droplets, but the electronics still need protection. Dry the board after testing and avoid corrosive liquids for long-term reliability.

Technical Specifications

Parameter Value
Sensor type Raindrop / water droplet detection module
Comparator LM393 dual comparator class circuit
Output types AO analog output and DO/S digital output
Operating voltage 3.3 V / 5 V
Sensing board area Approx. 5.0 x 4.0 cm
Surface finish Nickel-plated conductive traces
Sensitivity adjustment Onboard potentiometer
Digital behavior Typically high when dry, low when wet
Pinout GND, VCC, S/DO, A/AO
Connector 2.54 mm pitch pin header
Development support Arduino, ESP32, STM32, Raspberry Pi Pico ADC/GPIO

Board Layout & Label Guide

  • Sensing plate: Large conductive area where raindrops bridge traces.
  • LM393 comparator: Creates a clean digital threshold output.
  • Potentiometer: Adjusts digital wet/dry trigger point.
  • G pin: Power ground.
  • V pin: 3.3 V or 5 V power input.
  • S/DO pin: Digital rain detection output.
  • A/AO pin: Analog droplet-level output.

Application Scenarios

1. Rain or Water Presence Monitor

Read the sensor surface and print a simple moisture level for roof, window, or tabletop experiments.

const int ANALOG_PIN = A0;
const int DIGITAL_PIN = 2;

void setup() {
  pinMode(DIGITAL_PIN, INPUT);
  Serial.begin(115200);
}

void loop() {
  int wetLevel = analogRead(ANALOG_PIN);
  bool wetSwitch = digitalRead(DIGITAL_PIN) == LOW;
  Serial.print("analog=");
  Serial.print(wetLevel);
  Serial.print(" digital_wet=");
  Serial.println(wetSwitch ? "yes" : "no");
  delay(200);
}

2. Automatic Cover Trigger

Use a threshold to trigger a servo, relay, or warning output when water is detected.

const int SENSOR_PIN = A0;
const int OUTPUT_PIN = 8;
const int WET_THRESHOLD = 500;

void setup() {
  pinMode(OUTPUT_PIN, OUTPUT);
}

void loop() {
  int wetLevel = analogRead(SENSOR_PIN);
  digitalWrite(OUTPUT_PIN, wetLevel > WET_THRESHOLD ? HIGH : LOW);
  delay(100);
}

3. Moisture Trend Logger

Average several samples before logging so droplets, fog, or touch events are easier to compare.

const int SENSOR_PIN = A0;

void setup() {
  Serial.begin(115200);
}

void loop() {
  long total = 0;
  for (int i = 0; i < 16; i++) {
    total += analogRead(SENSOR_PIN);
    delay(5);
  }
  Serial.print("average_wet_level=");
  Serial.println(total / 16);
  delay(1000);
}

Packing List

  • 1 x Raindrop Sensor

FAQ

Q: Can this module work with Arduino?
A: Yes. Connect VCC, GND, and the signal pin to an Arduino-compatible board or an OpenELAB Sensor Shield V5.

Q: Can it work with 3.3 V controllers?
A: Yes for the listed 3.3 V to 5 V modules, but keep analog output within the controller ADC range.

Q: Is calibration required?
A: For threshold or quantitative use, calibrate in the final installation and record baseline readings.

Q: Can I use long wires?
A: Shorter wires are better for analog stability; use averaging in firmware if readings fluctuate.

Q: Does the module output precise engineering units?
A: Most of these modules provide relative analog or digital signals, not certified measurement data.

Q: What should I check first if it does not trigger?
A: Verify power, ground, pin mapping, threshold setting, and whether the signal is active-high or active-low.

Q: Is it suitable outdoors?
A: Only with enclosure protection. Keep connectors and electronics away from water and corrosion.

Q: Can it drive a relay or motor directly?
A: No. Use the module as an input to a controller, then drive a suitable relay or motor driver.

1. General Shipping Information

  • We provide reliable shipping services with a tracking number for each order.
  • Shipping addresses must be entered in English and should not contain special symbols, so that the courier system can recognize your location correctly.
  • 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.

🚀 Need Faster Shipping?

If you require expedited shipping, please contact our customer support team at info@upenelab.com for a customized quote based on your destination.

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.