Kesen.

OEM & ODM Manufacturing for Environmental Monitoring Instruments

Kesen manufactures for other brands. We build stack samplers, ambient monitors, VOC systems, water analyzers and optical gas sensor modules under customer names, model numbers, housings, firmware and documentation — from a nameplate change through to a fully re-engineered platform.

Discuss an OEM project
Optical sensor modules

The commercial point of this page

Every OEM enquiry is answered with the six numbers a buyer actually needs: minimum order quantity by model, non-recurring engineering cost and what it covers, tooling cost and who owns the tooling, lead time to first article, lead time to production, and warranty and RMA terms. Those numbers appear in the quotation, not on the website, because they depend on the gas, the range, the connector and the annual volume — publishing generic figures on a web page is how suppliers create an expectation they cannot meet.

What we can build for you

Private-label and white-labelYour brand, your model numbering, your documentation, your packaging, your serial-number scheme. Private-label models are not listed in our catalogue and are not offered to your competitors in your market.
Custom configurationMeasurement range, gas list, pump type, output protocol, display language, data software and connectivity built to your market requirements rather than to our catalogue default.
Optical sensor module supplySupply your own controller and housing; we supply the measurement core — light source, optical path, detector, signal processing — with firmware, communication protocol and calibration tooling.
Certification supportWe support your conformity assessment, technical file preparation and CE / UKCA marking documentation, and supply the test reports your notified body asks for.
Logistics and packagingYour box, your manual, your labelling, your documentation set and your carton specification for retail or project shipment.
Firmware and softwareDisplay language, data file format, PC software and any customer-specific protocol. Version policy and support commitment are stated in the agreement.

Optical gas sensor modules — the highest-margin part of this programme

If you build instruments rather than sell finished ones, the measurement core is the part worth buying rather than designing. Each module is a complete optical measurement engine supplied with the documentation needed to integrate it.

Technology Typical targets Why you would choose it over the alternative
NDIR CO, CO2, SO2, CH4, NOx, NH3 Non-dispersive, so no moving parts and a long service life. The default choice when the target gas has strong infrared absorption in the 4–7 µm band.
NDUV NO, NO2, O3, SO2 Non-dispersive ultraviolet. Suits gases with strong UV absorption, including ozone, which NDIR does not measure well.
NDVIS Visible-range species The visible variant, for applications where the sensing element is a photodiode array working in the visible range.
DOAS Long-path and open-path measurement Differential optical absorption spectroscopy for long-path, high-sensitivity and open-path work — stack monitoring at distance, fence-line perimeter measurement, open-path leak detection. A local point measurement is insufficient in these cases.

What arrives with every module

  • Interface specification and communication protocol — UART, I2C or RS485 as specified
  • Firmware outputting raw value, compensated value and diagnostic status
  • Calibration procedure and coefficients where applicable
  • Reference gas requirement for your stated measurement range
  • Mechanical drawing and connector type
  • Operating temperature, humidity and EMC requirements
Range and gas are the decisions that cannot be reversed

The light source and the optical path are determined by the target gas and the measurement range. Changing either after the housing is designed means redesigning the housing. This is the single most common reason an OEM project slips, and it is entirely avoidable: state your gas and range in the first enquiry, not after the first prototype.

Per-module specifications — wavelength, detection limit, response time, warm-up time, power consumption, dimensions — are supplied as factory datasheets on request. They are not published on this site because the module range is maintained as a separate document set rather than a public catalogue.

What we state before you commit

Item What is stated, and in what form
MOQ by model Standard configurations carry standard minimums. A custom gas, range, connector or housing changes both the minimum and the engineering cost. Stated in the quotation before you commit, not discovered afterwards.
NRE and what it covers Non-recurring engineering cost itemised: optical or hardware change, firmware development, tooling, documentation, and the specific deliverables each covers. You know what you are paying for and what you own at the end.
Tooling and ownership Who pays for tooling, who owns it, and what happens to it if the programme ends. Stated in writing in the agreement.
Lead time Two numbers, not one: time to first article, and time to production after first-article approval. Projects usually slip on the second, not the first.
Firmware support Version policy, how long versions are maintained, and what constitutes a change requiring notification. A private-label product that cannot be firmware-updated becomes a liability in your market.
Warranty and RMA Warranty period, RMA routing, who pays freight, and the target replacement turnaround. In the agreement, not in a policy document that can change later.
Channel protection Which models are private-label and therefore unavailable to other customers. This is the term most often left out and most regretted later.

How a private-label programme runs

  1. Specification agreement. Target market, application, gas and range, output protocol, quantity and the certification route you intend to follow. Most projects that fail do so here, because the certification route was decided after the hardware was designed.
  2. Quotation. MOQ, NRE itemised, tooling, lead time to first article, warranty terms and channel protection.
  3. Sample and pre-production unit. Delivered with a calibration record, so you can evaluate on your own bench rather than against a datasheet.
  4. Your conformity assessment and documentation review. We supply the test reports and technical file content your notified body or your own customer requires.
  5. First-article approval. Signed against an agreed test protocol, not a visual check.
  6. Production and serial tracking. Serial-number scheme, test records retained per unit, and a documented change-control process.
  7. Ongoing supply. Change-control notification before any component or firmware substitution. A silent substitution is how a qualified product stops being qualified.

What we need from you to quote an OEM project

Required for a quote Strongly recommended Nice to have at the first enquiry
Target gas or measurand Expected annual volume Target certification route and market
Measurement range and resolution Output interface and protocol Enclosure dimensions and mounting
Supply arrangement — module or complete instrument Display and user-interface language Packaging and labelling artwork
Quantity for the first order Whether you hold the design Forecast horizon and expansion plan

Send these by email with a datasheet or a method sheet attached if you have one. oem@kesensetech.com

One boundary, stated plainly

We build to your specification and to ours. We do not supply measurement cores for applications that fall outside environmental and process gas monitoring, and we will tell you early if a project falls outside what we can support well. A supplier who accepts everything and delivers late is a worse partner than one who declines a project in week one.