Building your own EMF detector: feasibility, cost, and whether it's worth it

I'm an engineer by trade, and I've been thinking about building an EMF detector from scratch rather than buying one. Budget's tight, and I'm curious whether it's actually possible to build something reliable and accurate without professional equipment.

The theory's straightforward - you need a sensing antenna, an amplifier circuit, and a display. The challenge is calibration and accuracy. Commercial detectors cost what they cost partly because they've been tested and calibrated to give reliable readings.

I've found some Arduino-based designs online that seem reasonable, though most are more about proof-of-concept than actual detection. Parts cost would be about £40-60 if I'm careful. But here's my question: would the result actually be usable for investigation work, or would I just end up with an expensive gimmick?

Has anyone else tried building detection equipment? What was your experience? And more broadly: does it actually need to be calibrated commercial equipment, or is DIY workable if you're just looking for relative changes rather than absolute values?

This is a genuinely interesting technical question. For investigation purposes, you probably don't need professional calibration - you're mostly looking for anomalies relative to baseline rather than absolute measurements. So a DIY detector could work if you're consistent about where and how you use it.

would I just end up with an expensive gimmick?

Probably, to be honest. Not because DIY is bad, but because EMF detection's already pretty contentious. If you're trying to demonstrate actual findings to anyone, they'll question your equipment. A commercial detector gives you at least some credibility.

I tried building one a few years back using an Arduino and some sensor components. It worked in the sense that it detected EMF, but it was erratic and I couldn't be confident about readings. Spent fifty quid and learned a lesson. If you're doing it for the technical challenge, brilliant - go for it. If you're hoping to use it for actual investigation, spend the money on a proper device.

The real issue with EMF detection for paranormal work is that there's no scientific consensus on whether ghosts actually produce EMF in the first place. So your detector could be perfect and it wouldn't matter - you're measuring something that might not be relevant. Worth considering before you sink time into building one.