Close view of a purple Blinky Hawk clipped to the side of an orange Keysight multimeter, the BLINKY HAWK name moulded into its housing in green, its indicator lit green. A wall outlet sits blurred behind it.
Available now · Built to order in Illinois · Patent pending

Blinky Hawk - Your DMM's BFF

Your DMM has a blind spot. It can't tell you when "0V" means "Open" and when it means "Closed."
Blinky Hawk watches that blind spot and tells you instantly: connected, open lead, or live.

A pocket-sized detector that piggybacks on your meter's voltage inputs. Same probes, same workflow, no mode switching — it watches continuously and tells you with a flash and a beep.

Buy now — $49.99 ▶ Watch the demo

$49.99 plus $9.00 USPS shipping · 30-day returns · one-year warranty · cancel any time before it ships

Two multimeters side by side on a countertop, each with a green Blinky Hawk attached. The left reads 0.0000 V with its detector lit green because its probes are touching; the right reads 118.5 V AC at a wall outlet with its detector lit orange.
The sales pitch

What problem does Blinky Hawk solve?

The problem: digital multimeters have a fundamental limitation. You set your meter to a voltage mode, probe two points, and read ~0 V. Is that true zero — or are you simply not connected: a floating probe, a clip that fell off, or a measurement across an isolation barrier?

Blinky Hawk tells you what “0 V” means, letting you work safer, faster.

Probe two points. Listen.

Single beep

No voltage. You didn't even have to lift your eyes.

Double beep

You have voltage (above ABS ~0.6 V). You also didn't even have to lift your eyes. A short-long beep instead means DC the other way around, and three beeps means AC.

No beep

Caution. Maybe you didn't make contact? If you were expecting voltage or continuity, you may have just found your problem.

The product

What you actually get

A self-contained, rechargeable detector with stacking banana plugs. It fits any meter with standard V/COM jacks — your probes plug into the back of it, and nothing about how you work changes.

A Blinky Hawk unit lying on a countertop, the BLINKY HAWK name moulded into its green housing, with its stacking banana pins at one end, the buzzer port, the USB-C charging slot, a short red lead and a loose orange stacking banana plug beside it. Behind it a Fluke 87V reads 118.5 V AC at a wall outlet with a second unit attached, lit orange.
The unit itself — stacking banana plugs, the LED/buzzer port, and USB-C for charging. Behind it, a second one calling out the 118 V at the outlet.
  • Three answers, not one. Open, closed, or live — shown on a colored LED and a buzzer, so it works whether or not you are looking at it.
  • It never leaves voltmeter mode. No ohmmeter circuitry exposed to a live circuit, and no pause to switch.
  • It tells you what kind of voltage. AC, DC, or DC with your probes reversed — each gets its own color sequence and beep rhythm, so you learn the polarity of a connection without reading the display.
  • Rechargeable. USB-C, roughly 60 hours of ordinary use per charge, and zero drain when switched off.
  • A three-position switch that also gives you a 100 kΩ test load — a fast way to tell a real supply from a phantom voltage.
  • Fully configurable. Sensitivity, alert patterns, brightness, and timing are all adjustable over USB with plain text commands. No reprogramming.

A closer look

A purple Blinky Hawk riding on the upper edge of an orange Keysight U1272A. The meter reads 0.0000 V with the two probe tips touching, and the round indicator on the detector is lit green to say the leads are closed.
It rides on the side of the meter, out of the way of the display and the dial — and the same unit moves to whichever meter you are using.
A purple Blinky Hawk standing on end on a stone countertop with the black hook-and-loop pad on its back facing the camera. In front of it sit the orange stacking-plug block with its banana pins upright, the purple cap that covers those pins, and mating hook and loop pads for your meter. A meter with a second unit attached is blurred behind.
Rear view — hook-and-loop on the back to attach it to your meter, plus the stacking-plug block, its cover, and spare pads.
A purple Blinky Hawk lying face-up on a stone countertop, the BLINKY HAWK name moulded into its housing in green, with the metal toggle switch at one end and a short red-and-black lead running to the stacking-plug block, which has the purple cover fitted over its banana pins.
Small and compact — and with the cover fitted over the banana pins, it works on its own as a standalone instrument.

Open by design

This is the whole circuit — not a redacted block diagram. The schematic and the firmware source are published, so you can see exactly what is across your probes, and change it if you want to.

Blinky Hawk V3 schematic: two 500 kilohm resistor ladders from the probe inputs meeting at a 100 kilohm sense resistor and an AO3400A bridge MOSFET, a TL431 reference, Schottky clamp diodes, an SK6812 LED, a buzzer across D8 and D9, and a pin-function table.
The board in full. The two 500 kΩ ladders and the 100 kΩ sense resistor are the 1.1 MΩ your probes see; Q1 is the bridge MOSFET the detection depends on.

At a glance

FitsAny meter with standard banana V/COM jacks — stacking plugs, probes go in the back
Tells youOpen leads / closed leads / voltage present — and whether that voltage is AC, DC+, or DC− — continuously
AlertsRGB LED and buzzer, both configurable (and both defeatable)
Working rangeDetection verified from 0 V through ±1 kV
Effect on your reading−5 mV of ghost voltage on open leads; nothing once a real voltage is present
Battery320 mAh internal lithium, USB-C charging, ~60 hours per charge
OpenFirmware source and schematics published in the project repo
Off means offThe switch disconnects the battery and both leads — your meter reads exactly as it would bare
ConfigurationStored on-board, adjustable over USB serial or the desktop app
Read the user guide Quick-start sheet (PDF) How it works →
Order one

Buy a Blinky Hawk

$49.99 + $9.00 USPS shipping

$58.99 before tax. Sales tax is worked out from your delivery address at checkout, so the final figure depends on where you are.

Built to order in Illinois, in small batches. Current lead time is one business day to three weeks, depending on where your order lands relative to the batch I am building.

  • Cancel any time before it ships. Full refund, no questions asked — you should never feel trapped by the lead time.
  • Thirty-day returns. Not happy with it? Send it back within 30 days of delivery for a full refund of the purchase price. Return shipping is at your expense.
  • One-year warranty. If something goes wrong in that window, you get a refund, a repair, or a replacement.
  • Need it by a specific date? Say so when you order and I will prioritize it at no extra charge. If the date is not realistic I will tell you rather than take your money.

Ships to United States addresses for now — the internal lithium cell brings real carrier restrictions I would rather solve properly than promise badly. Outside the US, email me and I will tell you where I have got to. The full terms live on the FAQ, shipping & returns page.

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Why it's different

Not “Smart Mode.” It never switches modes.

Some DMMs — or scripted bench meters — auto-switch to ohmmeter circuitry after a 0 V reading. That's just the user changing modes, automatically. The distinction here is fundamental, not incremental: it never leaves voltmeter mode at all.

 “Smart Mode” auto-switchThis design
SpeedPauses to switch modesContinuity checked at 20 Hz (up to ~500 Hz)
ExposureCan expose ohmmeter circuitry to live voltageNever leaves voltmeter mode — nothing fragile exposed
AdoptionBuy a whole new DMMStandalone — clip it onto the meter you already love
The payoff

What “0 V” can finally mean

Across the everyday things you probe, a normal meter gives you one ambiguous number. This gives you an answer.

Probes separated byNormal meterThis detector
Copper — same net0 V“Leads Closed”
Air gap0 V“Open Leads”
Open relay0 V“Open Leads”
Diode (unenergized)0 VFunction of polarity / type
Transformer pri↔sec (unenergized)0 Vmay read “Closed” (reactive coupling) *
Capacitor0 Vreads “Closed” while charging *
GPIO pin, output low0 V“Leads Closed”
GPIO pin, MCU off0 V“Open Leads”
Energized impedanceVoltageVoltage

* It measures impedance to a fast pulse, not pure DC continuity — so reactive parts can read “Closed” even with no galvanic path.

One honest limitation. Blinky Hawk detects a low-impedance path to a fast injected transient — which, the vast majority of the time, is a genuine wire-to-wire connection. Reactive components are the exception. A capacitor passes the transient and reads like a short that climbs as it charges (short → tens of kΩ → settling around 100 kΩ), so it can trip “Closed.” A transformer, winding-to-winding, couples that transient through its interwinding capacitance: one tested unit read >4 GΩ on a megohmmeter (galvanically wide open) yet still presented a low-impedance path and read “Closed.” So near reactive parts, treat a “Closed” as “low-impedance path,” not “guaranteed DC connection.”

A Fluke 87V propped on a countertop with its probes in a wall outlet, reading 119.4 V AC. The Blinky Hawk clipped to its side is lit orange.
Live is never ambiguous — the detector calls it before you read the display.
A small child kneeling on a rug, holding both multimeter probes onto a battery holder. The attached Blinky Hawk is lit orange to show voltage is present.
Simple enough for even little kids.
Under the hood

One MOSFET, one bridge, one transient

Blinky Hawk breaks a biased divider for an instant and watches how the node settles. The decay rate is the impedance between your probes — which is how it answers the question without ever becoming an ohmmeter.

The full engineering write-up has the circuit, the measured decay curves across every decade from 10 kΩ to open, the injected-signal safety numbers, the two hardware builds, and the open questions I am still chewing on.

Read how it works
Documentation

Everything that ships with it

Start here

Quick-start sheet

The one-page insert that comes in the box: hookup, the switch, what the lights mean, and the safety notes. Printable PDF.

Everyday use

User guide

Hookup, indicators, interpreting results, the 100 kΩ test load, battery and charging, safety, and troubleshooting.

Going deeper

Firmware manual

Every configuration key, the serial command reference, the low-power mode, and worked recipes for retuning a unit.

Make it your own

Source & schematics

The firmware source and the board schematics are published in the project repo, so the unit is completely customizable — change the behavior over USB, or change the code and reflash it yourself.

See it in action

Two minutes on the bench

Open leads, a real connection, and a live circuit — and what the meter shows in each case.

Ready when you are

Stop guessing what “0 V” means

$49.99 plus $9.00 shipping, built to order in Illinois. Cancel any time before it ships; 30 days to change your mind after it arrives.

Buy a Blinky Hawk

Stay in the loop

Blinky Hawk updates

Firmware releases, design changes, and whatever comes out of the workshop next. A few emails a year at most — and you do not need to be on this list to order one.