Home / Coded vs conventional magnets
Chapter 05 · The comparison
Coded vs conventional magnets
Not better — different where it counts. A conventional magnet is a bulk force; a coded magnet is a mechanism. Here is the whole comparison, including the one independent measurement on record.
| Property | Conventional dipole | Coded / programmable |
|---|---|---|
| Field reach | Long — power-law fade; grabs across real gaps | Short — exponential fade (e−2πz/λ); work under ~2 mm |
| Force at contact | Baseline | Higher on thin steel and coded mates; “4–5×” is vendor claim |
| Force curve | One fixed shape | A design variable — can cross zero, change sign, hold detents |
| Behaviors | Attract / repel | Align, latch, spring, twist-release, key, shear, torque, detent — composable in one part |
| Stray field | Everywhere — wipes cards, collects swarf | Engineered toward zero beyond ~0.25″ vendor claim |
| Identity | Any magnet mates with any steel/magnet | Coded pairs ignore wrong partners (lock-and-key) |
| Cost | < $2 (pair, plain N42 disc) | $10–40 (retail function pair) |
| Sourcing | Global commodity, thousands of suppliers | One primary IP holder + a few licensees; thin catalog |
| Where it wins | Reach, price, holding across gaps, motors/generators | Fasteners, closures, connectors, couplings, safety interlocks — anything at contact |
The one independent test
K&J Magnetics ran the closest thing to third-party validation this category has: an alternating-pole array out-pulled both a plain array and a Halbach array on a steel plate — 88 lb vs 72–77 lb, built from the same five cubes. That’s the near-field concentration effect measured by someone with no stake in it. It is directional support for the vendor strength claims — at contact, on steel — not a blank check for “5× stronger.”
And Halbach arrays?
The famous cousin. Both are engineered-magnetization multipoles with the same exponential near-field decay. The differences:
| Halbach array | Coded magnet | |
|---|---|---|
| Pattern | Periodic rotating magnetization | Aperiodic, correlation-designed N/S code |
| Result | One-sided, uniform flux | Arbitrary spatial force functions |
| Signature jobs | Motors, MRI, maglev, undulators (Mallinson 1973, Halbach 1980s) | Align wells, twist-release, springs, keys — behaviors a Halbach can’t express |
| Construction | Usually assembled from discrete magnets | Printed into ONE piece |
In the K&J pull test, the simple alternating-pole array beat the Halbach for raw pull on steel — a reminder that for contact force, local flux-closing is the whole game.
Rule of thumb
Need force across a gap, or a dollar magnet? Conventional. Need a behavior — self-alignment, gesture release, a click, a key, a contained field? Coded. The honest engineering summary of the entire category fits in that sentence.
Who owns this idea? The company & history →