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Cranial Electrical Stimulation Unit

Commercial cranial electrical stimulation (CES) units cost hundreds of dollars but this one is cheap and easy to build. It is battery-powered, portable and has adjustable current delivery and repetition rate.

By Robert Scott

Main Features

• Adjustable current (0.03-0.5mA)

• Adjustable repetition rate (0.5-
   100Hz in four steps)

• Battery powered

• Portable

• Flashing activity LED

• Automatic turn-off timer (25
   minutes) which can be reset

• LEDs indicate intensity of stimula-

• Long battery life (up to 100 hours
   continuous operation)


(1) This unit (or any other similar device) must not be used on a person who has a Heart Pacemaker or other implanted electronic device.

(2) Do not be tempted to run this unit from a mains adaptor, plugpack or power supply. This could be dangerous if a breakdown occurs in the isolating transformer.

No, this is not a do-it-yourself electroshock therapy project. The voltage and current used for Cranial Electrical Stimulation (also known as Transcranial Electrotherapy or Neuroelectric Therapy) is very low, ensuring that it is safe for the recipient. It does not cause a “shock” sensation or a lot of pain, although it can result in “pinpricks” at the higher settings.

However, at the voltage and current levels involved with this project there is no risk of injury.

We are not doctors so we can not say whether CES is beneficial. Some claim that it reduces anxiety, treats pain (especially headaches) and promotes alertness and relaxation. If you have investigated the potential benefits and would like to try CES, building this project is a cheap and easy way to do so.

We can’t rule out the possibility that the benefits from CES are a placebo effect but if true, such benefits are still real. If so, it would be a case of “mind over matter!”

What is CES?

CES involves passing a small amount of current through the recipient’s head. A proportion of this is thought to pass through the brain and create chemical changes which may influence mood.

Click for larger image
The Cranial Electro-Stimulator is built into a low-profile instrument case and is powered by four AAA 1.5V cells.

Obviously we must be careful to limit the amount of power that can pass through a sensitive organ like the brain. In this case, the current is limited to a maximum of half a milliamp (0.5mA) and the voltage is limited to 15V. Since the unit is powered from a small battery (four AAAs) rather than mains, there is no possibility that a fault could result in a fried noggin!

Commercial CES devices vary but generally deliver somewhere between 0.01mA to 1mA with a repetition rate between 0.5Hz and 100Hz. With this unit, both parameters can be adjusted, so you can find the combination that works best for you.

The Transcutaneous Electrical Nerve Stimulation or TENS unit published in SILICON CHIP, January 2006 is similar in some respects. That unit also relied on electrical stimulation of the human body but at higher voltage and current levels. However, as stated in the TENS article, these levels are unsuitable for use on the head or neck, so this CES unit has been designed to deliver much less power in order to make it safe.

Current is delivered to the patient via clip-on leads that attach to the ear lobes. While at first it may seem unlikely that just 15V can result in current conduction through the human body, the ear tingling and (at higher settings) pin-prick sensation demonstrates that a circuit is indeed made. Just how much current is flowing is indicated by the brightness of two LEDs on the front panel.

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