---
# System prepended metadata

title: 'How to test ultrasonic sensor with multimeter? '
tags: [Sensor]

---

You can do a basic health check of an [ultrasonic sensor](https://www.onzuu.com/category/ultrasonic-receivers-transmitters) with just a [multimeter](https://www.onzuu.com/category/multimeters), but you can’t fully test the distance-measurement function that way – for that you really want a [microcontroller](https://www.ampheo.com/c/microcontrollers) or [oscilloscope](https://www.onzuu.com/category/oscilloscopes).

I’ll break it down by [sensor](https://www.ampheo.com/c/sensors) type and show what a multimeter can tell you.

![m_Circuit_with_Multimeter_a7e61d15-65e4-4232-b566-a5ee37e24cb3_480x480](https://hackmd.io/_uploads/S10r2s-W-g.png)

**1. First: what kind of ultrasonic sensor do you have?**

Most hobby stuff is one of these:

**1. Digital “ping” module (e.g. [HC-SR04](https://www.ampheo.com/product/hc-sr04-26835950), HY-SRF05, etc.)**

* 4 pins: VCC, GND, TRIG, ECHO
* You send a trigger pulse, it returns pulse width on ECHO.

**2. Analog / 3-wire ultrasonic sensor**

* 3 pins: V+, GND, OUT
* OUT is a voltage proportional to distance.

**3. Industrial sensor (4–20 mA or 0–10 V output)**

* Often 3–4 wires, labeled with power & signal.

Your multimeter is most useful for type 2 and 3. For HC-SR04-style modules you can only do sanity checks.

**2. Basic health checks for any ultrasonic sensor (with a multimeter)**
**(a) Visual + continuity check (no power yet)**

1. Look for:

Burn marks, broken solder joints, cracked PCB.

2. Use continuity / resistance mode:

* Check that there’s no short between VCC and GND (should not beep).
* Check each pin is not shorted directly to another (do quick sanity checks).

If VCC–GND reads almost 0 Ω, the module is probably fried.

**3. Testing a 3-wire analog ultrasonic sensor (best case for multimeter)**

Pins: V+, GND, OUT.

**Step 1 – Power the sensor**

1. Connect a DC supply of the correct voltage (check datasheet / label, often 5 V, 12 V or 24 V).
2. Hook your multimeter in DC voltage mode to:

* Black probe → GND
* Red probe → OUT.

**Step 2 – Look for a distance-dependent output**

1. With no object nearby, note the output voltage (e.g. 0.5 V, 1.2 V, etc.).
2. Bring a flat object (book, cardboard) in front of the sensor at different distances:

* Close (10–20 cm)
* Medium (50 cm)
* Far (1 m+)

You should see OUT voltage change with distance (either increasing or decreasing depending on sensor type).

If:

* OUT is stuck at 0 V → no output, power issue, or dead sensor.
* OUT is stuck at supply voltage (e.g. always 5/12/24 V) → also suspicious.
* OUT responds smoothly as you move an object → sensor is basically working.

**4. Testing a 4–20 mA / 0–10 V industrial ultrasonic sensor**
**4–20 mA type**

1. Connect supply (+V and GND) as specified.

2. Put multimeter in current (mA) mode, in series with the signal loop:

* +V → sensor +
* Sensor output – → multimeter A/mA input
* Multimeter COM → supply GND

3. Move an object in front of the sensor:

Current should change between ≈4 mA (min distance or out of range) and ≈20 mA (max distance).

**0–10 V type**

1. Connect supply.
2. Measure between signal pin and GND in DC volts mode.
3. Move target: output should vary between 0 V and (roughly) 10 V.

If you see a good, repeatable change with distance → sensor is alive.

**5. What you can do with a multimeter on an HC-SR04-style module**

For modules like HC-SR04 (4 pins: VCC, GND, TRIG, ECHO):

**Step 1 – Check power and current**

1. Power the module with 5 V (as specified).

2. Set multimeter to DC voltage:

Check VCC–GND ≈ 5.0 V.

3. Optional: measure current draw by placing multimeter in series on the 5 V line:

Typical idle current is a few mA to tens of mA.

If it draws zero or a huge current → it’s likely dead or shorted.

**Step 2 – Check idle logic levels**

With the sensor powered and TRIG left unconnected (or pulled low):

* Measure TRIG pin to GND → should be near 0 V (if pulled low).
* Measure ECHO pin to GND → usually near 0 V (idle low).

If ECHO is stuck at 5 V or floating weirdly with no trigger, something might be wrong.

**Step 3 – Understand the limitation**

The distance information is encoded as a pulse width on ECHO that lasts a few hundred microseconds to a few milliseconds. A multimeter:

* Updates only a few times per second
* Averages the signal

So you cannot reliably see the timing of the ECHO pulse with a normal DMM. You might see some random, flickery voltage if you keep triggering it, but you can’t measure distance.

To really test these modules you need:

* A microcontroller ([Arduino](https://www.ampheo.com/c/development-board-arduino), [STM32](https://www.ampheo.com/search/STM32), etc.) to measure the pulse width, or
* An oscilloscope or logic analyzer to watch TRIG/ECHO.

**6. Quick summary**

With just a multimeter, you can:

* Check for shorts between power pins.
* Verify supply voltage and current draw.
* On analog / 4–20 mA [sensors](https://www.ampheoelec.de/c/sensors): actually see the output change with distance.
* On HC-SR04-style modules: only do basic power & pin sanity checks.

You cannot:

* Properly measure the echo pulse timing of digital ultrasonic modules.
* Fully validate their range accuracy with only a DMM.