Octopus
16
Sixteen spring-loaded pins that are the electrodes. No cables, no gel, no cap.
A small round board with two ADS131M08 converters and a Seeed Studio XIAO ESP32-S3 on top. Strap it over the back of the head and it streams 16 channels over Bluetooth, straight into a browser.
- Channels
- 16
- Electrodes
- Pogo pins, dry
- Converters
- 2 × ADS131M08, 24-bit
- Wireless
- Bluetooth LE, 250 SPS
- Brain
- XIAO ESP32-S3
- Power
- 5 V bank, up to 300 mAh
Where to use it
Sixteen pins packed into a few centimetres give you a dense look at one area, usually the visual cortex. Pick a use case and try the live demo.
Simulated signal to show the effect. Real recordings are noisier.
How to set it up
Mount the XIAO, flash the firmware from your browser, strap it on and connect. The last step keeps the pins working for years.
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1
Gather the kit
The board takes a Seeed Studio XIAO ESP32-S3 as its brain. It usually ships without its pins soldered, so check before you start.
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2
Mount the XIAO and the antenna
Line the XIAO up with the socket headers on the board, check the orientation against the photo in the connection guide, and press down gently until it’s fully seated.
Then snap the BLE antenna onto the small round connector on the XIAO. Without it, the Bluetooth range drops to almost nothing.
-
3
Flash the firmware from your browser
Plug the XIAO into your computer with the USB-C data cable, open firmware.pieeg.com in Chrome or Edge, click Install and pick the serial port. It takes about 30 seconds.
When it’s done, unplug and replug the board once. It then shows up over Bluetooth as
Octopus-16-XXXX. Try the installer on the right. -
4
Unplug from the computer, power it from a battery
Once flashed, disconnect the USB-C cable from the computer and run the board from a small 5 V power bank on the head band. A battery keeps the body isolated from mains power and keeps the signal clean.
Do
- 5 V power bank, up to 300 mAh
- 2 A maximum
- Bank fixed on the band, cable short
Don’t
- Wear it while plugged into a computer
- Wall adapters or chargers
- Large, heavy power banks
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5
Place it and check pin contact
Put the board over the back of the head, pins down, and hold it with the band. Set it straight on, at a right angle to the scalp: tilted pins lose contact and can jam.
Dry pins have to reach the skin through hair. Tighten the band until it’s snug but comfortable, and wiggle the board gently so the pins part the hair. Try it on the right.
0of 16 pins in good contactGoodWeakNone -
6
Connect in the browser
Open cloud.pieeg.com, find the Octopus 16 card under Connect Your Device and press Connect. Pick your board in the Bluetooth dialog and the stream starts: 16 channels at 250 Hz, filtered in the browser.
Web Bluetooth needs Chrome or Edge over HTTPS. Firefox, Safari and iOS don’t support it. Building your own page? The PiEEG JavaScript SDK connects in one call.
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7
Look after the pins
Each pin is a tiny spring in a barrel. Dust, hair, oil and sideways pressure can make one stick. Clean them regularly and they keep working.
A stuck pin often still works if it touches the skin. Contamination and wear from handling aren’t covered by the warranty.
Before you put it on anyone
- Octopus 16 is not a medical device and isn’t certified by any regulator. It’s for education, research and engineering, never for diagnosis or treatment.
- Only wear it on battery power. Unplug the USB-C cable from the computer first.
- Press gently. The pins should rest on the scalp, not dig in. Stop if the skin becomes sore or irritated.
- Building an SSVEP interface? Flickering stimuli can trigger seizures in people with photosensitive epilepsy. Screen participants and keep stimuli small.
- Don’t use it with a pacemaker or other implanted device without asking a physician.