HojellyTek supports optical liquid level sensing projects for buyers who need clearer level feedback, Installation compacte, and customization beyond standard on/off detection.
Most optical liquid level sensors use a photoelectric principle: une LED infrarouge envoie de la lumière dans la pointe d’un prisme, and a phototransistor or receiver detects the reflected light. Dans les airs, the prism reflects light differently than when it is wetted by liquid. The sensor circuit then converts this dry/wet optical change into a usable signal.
For a simple tank alarm, this signal can be an on/off output. For continuous or near-continuous level monitoring, the design may use a longer sensing structure, multiple optical points, or a signal-conversion design that reports level changes to a controller.
Our optical level sensing support can include:
For buyers comparing general solutions, voir notre Capteur de niveau optique Guide.

A photoelectric point level switch answers one question: “Is liquid present at this position?” It is ideal when the system only needs a clear dry/wet status. Par exemple, a coffee machine may need a low-water alert, a medical device may need a reagent-present signal, or a small tank may need overflow protection.
Continuous measurement answers a different question: “How much liquid is in the tank now?” This matters when a controller must track level change during filling, draining, Dosage, Dosage, or process operation.
In many projects, buyers first ask for an optical continuous level sensor, but after review, the correct design may be one of three options:
If your requirement is only “tank full” or “tank empty,” a point device is usually simpler. If you need level trend, refill timing, dosing amount, or process feedback, continuous or multi-point sensing is more suitable.
For fixed-point detection projects, compare our capteur de niveau ponctuel électro-optique.
For continuous optical level projects, the measurement range is not selected like a generic catalogue switch. It must match the tank depth, sensing zone, Position d’installation, liquid behavior, and required control accuracy.
A short reservoir may only need several optical detection points. A taller tank may require a longer probe or a custom sensing structure. A dosing chamber may need higher resolution across a narrow section rather than a long full-tank range.
Resolution depends on the sensing method. With a multi-point array, resolution is based on the spacing between each optical point. Closer spacing gives more level steps, but it also affects probe design, câblage, coût, and controller input requirements. With analog or digital continuous output, the usable resolution depends on the optical sensing design, Traitement du signal, liquid stability, and calibration method.
Buyers should define:
Output selection is one of the biggest buying decisions. A point switch normally uses a discrete output such as NPN, PNP, pousse-tira-pousse, or relay-style logic depending on the control circuit. This is suitable for alarms, pump start/stop, refill triggers, and interlock signals.
For continuous or process-level feedback, buyers often ask for analog output. A 4–20 mA signal is common in industrial control because it can represent a changing level over a defined range and is more suitable for longer cable runs than simple voltage signals. Digital output may be used when the sensor needs to communicate with a microcontroller, smart device, ou passerelle industrielle.
HojellyTek can review the controller requirement during RFQ and help match the output logic to your system. Tension d’alimentation, wiring mode, Longueur du câble, Connecteur, and signal behavior are confirmed before sample production.
Not every continuous-looking application needs a true continuous transmitter. In many compact OEM systems, a multi-point optical array is a practical alternative.
A multi-point design places several optical sensing positions along one probe or assembly. Each point detects whether liquid has reached that height. The controller then interprets the result as empty, faible, Douleur moyenne, haut, ou complet. For many devices, this is enough to control refill, Prévention du fonctionnement à sec, stop overflow, or estimate remaining liquid.
This approach is useful when:
Multi-point arrays are often used in reagent tanks, water reservoirs, cleaning-fluid cartridges, Réservoirs de pétrole, fuel monitoring modules, Appareils connectés, Équipement de laboratoire, and compact industrial devices.
For oil-water or liquid-interface projects, voir notre optical interface level sensor.
| Exigence | Photoelectric Point Switch | Multi-Point Optical Array | Continuous Optical Sensing |
|---|---|---|---|
| Main purpose | Detect liquid at one fixed position | Detect several fixed level zones | Track changing level across a defined range |
| Typical output | NPN, PNP, digital on/off | Multiple digital signals or encoded output | 4–20 mA, Tension, Numérique, ou un signal personnalisé |
| Meilleur choix | Plein, vide, déborder, fuite, high/low alarm | Low/medium/high indication, stepped refill control | Dosing, process feedback, tank trend monitoring |
| Résolution | One detection point | Based on point spacing | Based on sensing design and signal processing |
| Design complexity | Le plus bas | Douleur moyenne | Maximum |
| Buyer should choose it when | Only dry/wet status is needed | Several level steps are enough | The controller needs variable level feedback |
Continuous and multi-point optical sensing is useful when mechanical floats are too large, can stick, or do not fit the product design. Because the sensing tip has no moving float arm, it is suitable for compact equipment where space is limited.
Common uses include:
For smart product designs, Tuya/Smart Life integration may be discussed where the sensor is part of a larger connected monitoring system.

Avant de demander un devis, préparez les détails suivants:
HojellyTek est un fabricant de capteurs optiques et de niveau liquide de Shenzhen disposant d’un système R interne&D, photoelectric sensing experience, and OEM/ODM customization support. Instead of forcing every buyer into a standard point switch, we help review whether your product needs a point sensor, multi-point array, or continuous-level signal design.
Buyers can also review our Produit capteur de niveau optique page before sending drawings or application details.
Non. An optical point switch detects liquid at one fixed position. An optical continuous level sensor or multi-point design gives level feedback across a range or several height zones.
Oui, 4–20 mA can be specified for projects that need variable level feedback. The sensing range, signal scaling, câblage, and controller input should be confirmed during RFQ.
Use a multi-point array when you need several fixed level stages, such as low, Douleur moyenne, and high, but do not need a fully smooth continuous transmitter signal.
PSU is common for many water-based uses. PTFE, 316 Acier inoxydable, or glass may be considered for chemicals, Huiles, Carburants, high cleanliness requirements, or more demanding liquid contact.
Common risks include dirty prism tips, coating liquid, écume, bulles, condensation, poor mounting position, Matériau incompatible, Câblage incorrect, or choosing a point switch when the process needs continuous feedback.
Envoyez votre dessin de char, Type liquide, Plage de mesure, signal de sortie, Méthode de montage, Tension, Exigence du câble, and expected application. Vous pouvez demander un devis par WhatsApp ou par e-mail.
Need continuous level feedback instead of a simple on/off signal? Envoyez votre dessin, Détails sur le liquide, Sortie requise, and installation plan to HojellyTek. Our team can help you choose between a point optical switch, multi-point optical array, or continuous optical level sensing solution for your OEM or industrial project.