EC Sense DS4 / Smart Digital Gas Sensors
Smart digital gas sensors covering 17 gas types across 38 models. Printed solid-polymer electrochemical technology in the standard industrial Size-4 package (20 × 16.6 mm cylindrical housing, three pins: VCC / GND / IO), with a UART 3.3 V half-duplex single-bus output that reports concentration directly. Factory pre-calibrated, no warm-up, measuring on power-up, drawing ≤ 5 mW at 5 V, with sleep/wake support and hot-pluggable installation — drop it into an existing socket and read the value.
A bare cell outputs a nanoamp-level analog current. Turning that into a usable concentration value means building your own amplifier, temperature compensation, ADC stage and calibration rig, then writing the firmware. The DS4 packs all of it into a 20 × 16.6 mm cylindrical housing and hands you the concentration in ppm over a single UART line.
| Aspect | Bare Sensor Cell | DS4 Smart Digital Sensor |
|---|---|---|
| Output Signal | nA – µA analog | UART 3.3 V half-duplex single bus, reporting concentration in ppm |
| Calibration | Build your own rig, gas calibration required | Factory pre-calibrated; an open protocol supports offline secondary calibration and one-click factory reset |
| External Circuitry | Custom amplifier, temp compensation, ADC, firmware | None — three pins (VCC / GND / IO) are all it takes |
| Integration Effort | Weeks to months | Seat it, power it up, read it — under 2 min to stabilize |
| Form Factor & Service | Soldered onto the board — replacement means reworking the PCB | Standard Size-4 housing, hot-pluggable; lifetime and performance self-check with early fault warning |
| Best For | High-volume instrument makers with in-house calibration | Instrument builders who need to ship quickly, or want sensors swapped in the field |
Selection Guide
The DS4 covers 17 gas types across 38 models, and most gases come in several ranges. Work through the sequence below and most projects settle on a single model inside ten minutes.
Decide what you are measuring, then what else is present on site. Background gases drive interference risk: if you are measuring VOCs alongside high CO or NO₂, metal-oxide approaches are largely ruled out. Our electrochemical sensors optimise electrode chemistry and bias per target gas, and cross-sensitivity data is published in each model's datasheet.
The usual mistake is buying the widest range available — wider range means coarser resolution. A practical rule: pick a range two to five times your alarm setpoint. For H₂S, where occupational limits sit around 10 ppm, a 0 – 100 ppm model is enough; you do not need 0 – 5000 ppm. Every range for every gas is listed in the matrix below.
Electrochemical sensing excels at ppm-level toxic and harmful gases, but it is not universal. For %LEL combustible-gas alarms, catalytic bead or infrared is the right choice; for broad-spectrum ppb-level VOC scanning and compound identification, you need a PID. The table below puts the four technology routes side by side so you can check the direction before choosing a model.
The DS4 has exactly one interface: UART 3.3 V half-duplex single bus, 9600 bps, 8N1, on three pins (VCC / GND / IO). Supply is 3.3 – 12 V DC (5 V recommended), with 1 mA peak current and 0.35 mA in sleep (0.5 mA for the O₂ version). If your project needs I²C, or needs the sensor to report ambient temperature and humidity itself, see the comparison with the TB600B&C below.
The DS4 uses the standard industrial Size-4 form factor (20 × 16.6 mm cylindrical, 4.56 g) and drops straight into an existing socket of the same standard. Confirm the site stays within -40 ℃ to +55 ℃, 15 – 95% RH (non-condensing) and atmospheric pressure ±10%, and whether your project needs RoHS or similar compliance documents — certification status is stated in each model's datasheet, and we can supply the reports we hold. Warranty is 12 months.
Pick the wrong sensing principle and no amount of good electronics will save the project. The table below sets out the boundaries of all four routes — the electrochemical column reflects this series' published specifications; the others are industry-typical ranges.
| Specification | Electrochemical (DS4 Smart Digital Sensor) | Catalytic Bead | NDIR Infrared | MOS Semiconductor |
|---|---|---|---|---|
| What It Measures | Ppm-level toxic gases (CO, H₂S, O₂, NH₃, O₃, TVOC and 11 more) | Total combustible gas (%LEL) | IR-active gases: methane, CO₂, SF₆ and similar | Reducing gases (ethanol, VOCs, some combustibles) |
| Resolution & Lower Limit | Down to 0.01 ppm (TVOC-10); 0.1 – 1 ppm typical | %LEL scale, typically 1% LEL | ppm to %VOL, depending on path length | Ppm level, with substantial baseline drift |
| Selectivity | High — electrode chemistry and bias optimised per target gas | Low — one total combustible figure | High, but limited to IR-active gases | Low, with pronounced cross-sensitivity |
| Response Time | < 3 s (T90 30 – 130 s, gas dependent) | 10 – 30 s | 1 – 10 min | Seconds to tens of seconds |
| Power Draw | ≤ 5 mW @ 5 V; 0.35 mA in sleep | High — heated catalytic bead | Medium to high — IR source required | Medium to high — heated element |
| Lifetime & Maintenance | > 3 years, no consumables; offline secondary calibration supported | 2 – 5 years, periodic calibration; prone to silicone poisoning | 5 – 10 years, optical cell must stay clean | Shorter life; drift requires frequent correction |
| Typical Applications | Industrial safety, leak detection, portable and battery-powered devices, IoT nodes | Combustible gas alarms (%LEL), gas and petrochemical sites | Gas networks, biogas, greenhouse-gas online monitoring | Low-cost consumer alarms and trend monitoring |
The catalytic and NDIR columns describe combustible-gas (%LEL) alarm practice and the MOS column covers common low-cost alarm designs; all three are industry-typical ranges rather than specifications of our products. The electrochemical column reflects the published DS4 datasheets.
Both series are EC Sense solid-polymer electrochemical products with equally reliable readings; they differ in form factor and interface. There is a single deciding question: do you want a sensor that drops into an existing socket, or a module with temperature/humidity sensing that talks on a bus?
Best for: portable and battery-powered devices, field replacement of existing Size-4 sockets, single-gas instruments and IoT nodes.
Best for: projects needing ambient temp/RH compensation, several modules sharing one I²C bus, or building a finished instrument or online monitoring system straight from the module.
Both series report concentration directly; the choice comes down to form factor, interface and whether you need temperature and humidity. If you are unsure, send us the application — we will tell you which series fits, including when neither does and a different principle is the better answer.
17 gas types across 38 models, with resolution down to 0.01 ppm and ranges up to 10,000 ppm and 25% VOL. Click any model to open its detail page and download the datasheet.
All 38 order numbers grouped by target gas. Use the filters below to narrow down by gas and Interface.
| Target Gas | Model | Range | Interface | Order No. | Datasheet |
|---|---|---|---|---|---|
| Carbon Monoxide | DS4-CO-100 | 0 – 100 ppm | UART | 04-DS4-CO-100-01 | |
| Carbon Monoxide | DS4-CO-1000 | 0 – 1000 ppm | UART | 04-DS4-CO-1000-01 | |
| Carbon Monoxide | DS4-CO-10000 | 0 – 10000 ppm | UART | 04-DS4-CO-10000-01 | |
| Acetylene | DS4-C2H2-20 | 0 – 20 ppm | UART | 04-DS4-C2H2-20-01 | |
| Acetylene | DS4-C2H2-100 | 0 – 100 ppm | UART | 04-DS4-C2H2-100-01 | |
| Acetylene | DS4-C2H2-500 | 0 – 500 ppm | UART | 04-DS4-C2H2-500-01 | |
| Ethylene | DS4-C2H4-20 | 0 – 20 ppm | UART | 04-DS4-C2H4-20-01 | |
| Ethylene | DS4-C2H4-100 | 0 – 100 ppm | UART | 04-DS4-C2H4-100-01 | |
| Ethylene | DS4-C2H4-500 | 0 – 500 ppm | UART | 04-DS4-C2H4-500-01 | |
| Methyl Mercaptan | DS4-CH4S-100 | 0 – 100 ppm | UART | 04-DS4-CH4S-100-01 | |
| Methyl Mercaptan | DS4-CH4S-5000 | 0 – 5000 ppm | UART | 04-DS4-CH4S-5000-01 | |
| Chlorine | DS4-Cl2-10 | 0 – 10 ppm | UART | 04-DS4-Cl2-10-01 | |
| Chlorine | DS4-Cl2-50 | 0 – 50 ppm | UART | 04-DS4-Cl2-50-01 | |
| Chlorine | DS4-Cl2-100 | 0 – 100 ppm | UART | 04-DS4-Cl2-100-01 | |
| Ethylene Oxide | DS4-ETO-200 | 0 – 200 ppm | UART | 04-DS4-ETO-200-01 | |
| Ethylene Oxide | DS4-ETO-1000 | 0 – 1000 ppm | UART | 04-DS4-ETO-1000-01 | |
| Hydrogen | DS4-H2-1000 | 0 – 1000 ppm | UART | 04-DS4-H2-1000-01 | |
| Hydrogen | DS4-H2-20000 | 0 – 20000 ppm | UART | 04-DS4-H2-20000-01 | |
| Hydrogen Sulfide | DS4-H2S-100 | 0 – 100 ppm | UART | 04-DS4-H2S-100-01 | |
| Hydrogen Sulfide | DS4-H2S-500 | 0 – 500 ppm | UART | 04-DS4-H2S-500-01 | |
| Hydrogen Sulfide | DS4-H2S-1000 | 0 – 1000 ppm | UART | 04-DS4-H2S-1000-01 | |
| Hydrogen Sulfide | DS4-H2S-5000 | 0 – 5000 ppm | UART | 04-DS4-H2S-5000-01 | |
| Formaldehyde | DS4-HCHO-100 | 0 – 100 ppm | UART | 04-DS4-HCHO-100-01 | |
| Hydrogen Cyanide | DS4-HCN-50 | 0 – 50 ppm | UART | 04-DS4-HCN-50-01 | |
| Ammonia | DS4-NH3-100 | 0 – 100 ppm | UART | 04-DS4-NH3-100-01 | |
| Nitrogen Dioxide | DS4-NO2-100 | 0 – 100 ppm | UART | 04-DS4-NO2-100-01 | |
| Nitrogen Dioxide | DS4-NO2-1000 | 0 – 1000 ppm | UART | 04-DS4-NO2-1000-01 | |
| Oxygen | DS4-O2-25% | 0 – 25 %vol | UART | 04-DS4-O2-25%-01 | |
| Ozone | DS4-O3-50 | 0 – 50 ppm | UART | 04-DS4-O3-50-01 | |
| Ozone | DS4-O3-100 | 0 – 100 ppm | UART | 04-DS4-O3-100-01 | |
| Phosphine | DS4-PH3-20 | 0 – 20 ppm | UART | 04-DS4-PH3-20-01 | |
| Phosphine | DS4-PH3-2000 | 0 – 2000 ppm | UART | 04-DS4-PH3-2000-01 | |
| Sulfur Dioxide | DS4-SO2-100 | 0 – 100 ppm | UART | 04-DS4-SO2-100-01 | |
| Sulfur Dioxide | DS4-SO2-1000 | 0 – 1000 ppm | UART | 04-DS4-SO2-1000-01 | |
| TVOC | DS4-TVOC-10 | 0 – 10 ppm | UART | 04-DS4-TVOC-10-01 | |
| TVOC | DS4-TVOC-200 | 0 – 200 ppm | UART | 04-DS4-TVOC-200-01 | |
| TVOC | DS4-TVOC-1000 | 0 – 1000 ppm | UART | 04-DS4-TVOC-1000-01 | |
| TVOC | DS4-TVOC-2000 | 0 – 2000 ppm | UART | 04-DS4-TVOC-2000-01 |
No. Every sensor is professionally calibrated with the matching standard gas before shipment, so it outputs a usable concentration value as soon as it powers up — no secondary gas calibration. An open calibration protocol is also provided: if you have your own calibration workflow you can run an offline secondary calibration, and restore the factory parameters with one command.
Three things decide it. Form factor: the DS4 is a standard Size-4 cylindrical sensor (20 × 16.6 mm, hot-pluggable) while the TB600B&C is a module board. Interface: the DS4 offers only a UART 3.3 V single bus; the TB600B&C comes in UART and I²C versions. Environmental data: the TB600B&C includes temperature/humidity sensing with on-board compensation, while the DS4 reports gas concentration only. Choose the DS4 for compact, low-power products that fit an existing socket; choose the TB600B&C when you need temp/RH compensation or several units on one bus.
No, and this point matters. The DS4 is a ppm-level toxic and harmful gas sensor: it can measure leakage concentrations in ppm for gases such as hydrogen, acetylene, ethylene and methyl mercaptan (H₂ is covered at 0 – 1000 and 0 – 20,000 ppm), but its ranges and resolution are designed around occupational exposure limits and leak detection, not %LEL alarms. For %LEL combustible-gas alarms, choose a catalytic bead or infrared sensor.
The DS4 does not provide I²C — its output is a UART 3.3 V half-duplex single bus, using one line for both directions. If you need several sensors on a shared bus or an I²C interface, choose a TB600B&C module (available in an I²C version). The DS4 also provides self-identification, so a host can read back the sensor's identity — useful when you want a device that recognises which gas was plugged in.
Yes. Total consumption is ≤ 5 mW at 5 V — 0.65 mA working, 1 mA peak and 0.35 mA in sleep (0.5 mA for the O₂ version) — with a 3.3 – 12 V DC supply range. Combined with no warm-up, a stable reading within 2 minutes of power-up, and sleep/wake support, it suits portable instruments, wireless sensor nodes and IoT devices.
Operating temperature is -40 ℃ to +55 ℃, humidity 15 – 95% RH (non-condensing), and pressure atmospheric ±10%; the housing is ABS and the sensor weighs 4.56 g. Accuracy is ± 5% F.S, repeatability better than ± 2%, long-term sensitivity drift under 1% per month, expected lifetime beyond 3 years in air, and warranty 12 months. The sensor also self-checks lifetime and performance so faults surface early.
Every datasheet is downloadable from its product page on this site. For samples and volume pricing, send us the target gas, range, annual volume and the form factor of your instrument through the contact form or by email, and we will quote the matching model and order number with lead time.
Send us your target gas, range requirement and instrument form factor — we will match the model and quote it. Datasheets for all 17 gas types and 38 models are available to download now.
