What is it?

This electronic circuit detects changes in local electro-magnetic fields and converts them to human-audible sounds.

Electro-magnetic fields are all around us, but are usually invisible and silent. This detector uses two inductors to give a stereo audio output of the noise created by electro-magnetic fields.

This is useful for investigating electronic circuits, checking power supplies and investigating the unseen world around us.

This kit includes a high-quality PCB, all the components, an enclosure and a pair of in-ear earphones.

This is an easy kit to build and should take in the region of 1 hour to construct.

**Note:* The sensors need to be close to the device being measured (touching the outer sheath of a cable for example). The output totally depends upon the EMF field so the stronger the field, the louder the sounds.*

Parts included in this kit:

• PP3 Battery Clip
• 100uf Capacitor x2
• 2.2uf Capacitor x4
• 100k Resistor x2
• 1k Resistor x 3
• 390k Resistor x2
• 5mm Red LED
• Switch
• Jack Phone Socket
• OPA2134 Op-Amp
• 22mH Inductors x2
• 8 Pin IC Holder
• In-ear headphones
• Enclosure - Laser-cut acrylic
• M3 Hex spacers 9mm
• M3 6mm machine screws
• M3 10mm machine screws

Instructions

The instructions for are available here.

Full PCB files, enclosure and schematic files are available on GITHUB here.

I send items from the UK. Typically using Royal Mail 'Tracked 48' service in the UK. Orders for overseas (both EU and worldwide) will be sent with the most appropriate mail service, but usually Royal Mail international tracked.

I aim to send items within 3-5 working days (typically 1-2 days).

For international customers outside the UK: Import duties, taxes and all other fees are the recipient's responsibility.