Baseline Scan and Electrical Interferences Explained
For a baseline scan you need to get your sensor into a “zero signal” state so that the system can record what level of background (noise) is present. With TENS pads you do this by sticking them together (essentially shorting them out). When using hand cylinders the idea is similar—you need to temporarily have the electrodes not be influenced by your body.
A common method is to connect the hand cylinders together (using a short cable or by holding them firmly in contact with each other) so that they are effectively “shorted.” This creates a baseline reading that reflects only ambient noise. Once the baseline is recorded (and saved in the Spooky2 software), you then attach the hand cylinders to your body for the actual biofeedback scan. The baseline is then used to subtract out any background interference, ensuring your scan results are as accurate as possible.
Shorting the TENS pads together creates a true “zero” or reference point. When the pads are physically stuck (shorted), they’re electrically connected so that any voltage difference between them is minimized—this means the system only picks up ambient electrical noise, not any body-generated signals. If the pads were merely apart, even if not attached to your body, they might still register stray electrical interference or noise.
By shorting them, you ensure that the baseline scan captures only the inherent background signal (often referred to as “baseline” noise). This reference is then subtracted from subsequent scans, helping the system to accurately isolate the biofeedback signals produced by your body. In essence, it’s all about setting a clean, stable reference so that the later measurements reflect only the changes caused by your body’s response.
Stray electrical interference refers to the unwanted electrical signals that are always present in any environment. These signals aren’t “magical”—they come from many common sources. For example:
- Electrical wiring and appliances: Devices such as computers, fluorescent lights, and even power lines emit electromagnetic fields.
- Radio frequency interference (RFI): Wireless devices like mobile phones, routers, and radios also contribute to ambient electromagnetic noise.
- Cables acting as antennas: When electrodes or cables are left unshorted, they can pick up these stray signals much like an antenna, adding to the overall noise.
Shorting the TENS pads together forces the electrical potential between them to equalize, effectively “zeroing out” any differences. This process ensures that when you perform a baseline scan, the reading reflects only the inherent background noise of your system rather than external interference. This clean baseline is then used to subtract out the ambient noise from your actual biofeedback scan, so the signals you later detect are truly from your body's response.
Q : Can you make a complete list of all sources of those "Stray electrical interference" ?
It's virtually impossible to compile an absolutely complete list because almost any electrical or electronic device (or natural phenomenon) can emit electromagnetic signals. However, here’s a comprehensive list of many common sources of stray electrical interference:
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Mains Power & Building Wiring
• Power lines, transformers, and substations
• In-wall electrical wiring and outlets
• Electrical noise from switching circuits in your home’s power supply -
Household Appliances & Electronics
• Refrigerators, microwaves, and other kitchen appliances
• Computers, televisions, and monitors
• LED lights, fluorescent lamps, and other lighting systems
• Chargers and adapters (especially those with switching power supplies) -
Office & Industrial Equipment
• Printers, copiers, and other office electronics
• HVAC systems, industrial motors, and generators -
Wireless Communication Devices
• Smartphones, tablets, and cordless phones
• Wi-Fi routers, modems, and Bluetooth devices
• Radio and television broadcast signals; nearby cell towers -
Cables & Connectors
• Unshielded cables or poorly shielded wiring (which can act like antennas)
• Improperly terminated or connected cables -
Other Electronic Devices
• Medical equipment (e.g., MRI machines, defibrillators) when operating nearby
• Various consumer electronics with internal oscillators and converters -
Natural Sources & Environmental Factors
• Atmospheric phenomena such as lightning or thunderstorms
• Cosmic electromagnetic background (though extremely low in intensity)
• Static electricity from friction (triboelectric effects)
Each of these sources contributes to a background level of electrical "noise" that your biofeedback system might pick up. Shorting sensors like TENS pads together ensures that any stray differences (from these myriad sources) are nullified, giving you a stable baseline reading. This baseline is critical because it lets your system subtract out ambient interference, ensuring that subsequent readings are due to your body's actual response rather than external noise.
While this list covers the most common sources, keep in mind that in any given environment, many other minor or situational factors could add to the overall interference.
Here are some practical tips to help minimize stray electrical interference during a biofeedback scan:
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Choose a Quiet Location:
- Perform the scan in a room with minimal electrical activity. Ideally, select a space away from large appliances (like microwaves, refrigerators, or HVAC systems), computers, Wi-Fi routers, and mobile phones.
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Turn Off Unnecessary Electronics:
- Before starting your scan, power down or unplug devices that aren’t essential. This reduces ambient electromagnetic noise from devices like fluorescent lights, chargers, or TVs.
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Use Shielded Cables and Proper Grounding:
- Make sure the cables connected to your sensors are properly shielded. This helps prevent them from acting as antennas that pick up stray signals. Also, ensure your system is well-grounded if possible.
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Maintain a Safe Distance from Power Sources:
- Try to keep your scanning area away from power outlets and wiring where possible, as these can be significant sources of electrical noise.
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Minimize Movement and Metallic Objects:
- Ensure that there are no unnecessary metallic objects or moving parts near your sensors. Even small metal items can sometimes pick up or reflect interference.
(Source : ChatGPT-4)
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