Accurately measures distances using ultrasonic waves
Operates on a working voltage of 3.3 to 5 V
Capable of measuring distances from 2 to 350 cm
Compact and lightweight, weighing just 86g
The Dagu Ultrasonic HC-SR04 Distance Measurement Sensor Module is designed to gauge distances by transmitting and receiving ultrasonic waves. The module measures the time taken for the sound to bounce back from an object and return to the sensor. By utilizing the time difference and the speed of sound propagation, the module can accurately calculate the distance between itself and any obstacles in its path.
The module operates on a working voltage of 3.3 to 5 V. It is capable of measuring a minimum distance of 2 cm and a maximum distance of 350 cm. The compact module, weighing 86g, has dimensions of 43 x 25 mm.
The module employs an input digital signal known as the echo, and an output digital signal referred to as the trig. The module is activated by inputting a high level of more than 10us to the trig pin. Upon completion of the ranging process, the echo pin will output a high level, with the level width being the sum of the ultrasonic round-trip time.
If you are not satisfied with a product purchased from the Site, you may request a return within 30 days from the delivery date, unless the product is listed under the Return Exceptions below or is subject to specific return conditions noted on the product page.
This return policy also applies, as a minimum standard, to products sold and fulfilled by third-party vendors through the Marketplace.
United Kingdom consumers exercising their statutory Right of Cancellation are subject to different conditions. See the Statutory Right of Cancellation.
Returns under this policy concern non-defective products. In the case of a confirmed manufacturing defect, remedies are handled under the Warranty terms, at the Vendor's discretion. See the Warranty section.
Return Conditions
To qualify for a refund under the 30-day return policy, all of the following conditions must be met:
A valid Return Authorisation (RA) number must be obtained prior to returning the product. Returns without an RA number will be refused.
The RA number is valid for 30 days. The returned item must be received within that period.
The RA number must be included with the return.
Products must be returned in unused, unmodified condition (e.g., no scratches, alterations, missing parts, or signs of installation/use) and in their original packaging, suitable for resale.
Shipping fees are non-refundable. Return shipping costs are the responsibility of the customer, except in cases of a product confirmed defective through RobotShop's troubleshooting process or of a verified shipping error by RobotShop.
Refunds are processed within 7 days after receipt and inspection of the returned item.
A £100 cleaning fee may apply to domestic robots returned in used or unclean condition.
A 20% restocking fee may apply to large-quantity returns of items ordered specifically for the customer from the manufacturer or not part of RobotShop's standard inventory.
Return Exceptions
The following products are not eligible for return or refund under this policy:
Used, damaged, or modified products — Items that show signs of use, wear, or alteration, making them unsuitable for resale.
Consumables * — Use and wear-and-tear components, altered or depleted through use (e.g., batteries, belts, brushes, gears, filament, tyres, disposable bags, lubricants, greases, waxes, etc.). Not eligible for return once opened or used.
Perishables — Goods liable to deteriorate or expire rapidly. Not eligible for return.
Sealed goods (health or hygiene) — Items sealed for health-protection or hygiene reasons (e.g., masks, gloves, odour-absorbing products). Not eligible for return once unsealed.
Build-it-yourself products and items requiring customer assembly * — Including robots & kits, robot parts, and other products requiring assembly or soldering. Not eligible for return once assembled, soldered, or installed.
Digital Goods, Software, and Apps * — Final sale only, due to licensing restrictions.
Clearance Items * — Products identified as clearance or final sale, including end-of-life or discontinued items.
Custom-made, personalized, or special-order items — Products manufactured, configured, adapted, or built to the customer's own specifications and requirements.
On-Demand Items * — Standard catalogue products not stocked by RobotShop and ordered specifically to fulfil a customer request.
* United-Kingdom consumers retain their statutory Right of Cancellation on these items. Its exercise is subject to the conditions and exclusions set out in the Statutory Right of Cancellation, and any reimbursement may be reduced to reflect a loss in value resulting from handling beyond inspection.
How to Request a Return Authorisation (RA)
While the same return policy applies, these orders require a separate contact process for returns.
RobotShop Fulfilled Orders → submit a support ticket from your account under My Support Tickets.
Marketplace Vendor Orders → submit a ticket from your account under My Marketplace Tickets to contact the vendor directly.
Note: Marketplace vendor products are normally labelled with SKUs starting with RM, and identified on the product page with the mention "Sold and fulfilled by [Vendor Name]".
