diy_ tdcs transcranial dc stimulator _ tao currents - classical taoism as a religion

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DIY: TDCS Transcranial DC Stimulator

05 Monday Aug 2013

POSTED BY NEUTRINOZ IN ACUPUNCTURE, HEALTH, MEDICINE

COMMENTS OFF

Warning: TDCS has

been clinically provento affect brainfunction. Consult a

doctor before usingthis device.

Transcranial DCStimulation (tou lu

zhi liu dian qi ji ) or TDCS

is a non-invasive,

electronic treatmentfor mental disorders

and cognitiveimprovement, similar

to acupuncture in

operation, but forhealing the brain.Like acupuncture,

TDCS can regulate the flow and balance of chi. Anodal (+) TDCS stimulates; cathodal (-) TDCS calms.Different from acupuncture, TDCS can polarize an electrical pathway across the brain. It works bypassing a very small electrical current (1 to 2 mA DC) through the scalp, into brain tissue, repairing

neural functions and connections. DC stimulation can polarize or depolarize, because the DC (directcurrent) electricity is unidirectional and can redirect the flow of charge inside the brain. Portable TDCSstimulators (like the one described here) are as convenient to carry and use as swallowing a pill.

Commercial TDCS machines can cost several hundred to several thousand dollars. This project costsaround $15 in parts alone, but add another $40 for tools like a soldering iron, current meter andmiscellaneous parts, if not already owned.

Background:

TDCS complements acupuncture for comprehensive holistic therapy of mind and body. At this time,

the World Health Organization recognizes only one mental disease that can be effectively treated withacupuncture: depression. One limitation of acupuncture is that the needles cannot penetrate the skull



safely (excluding laseracupuncture which

can penetrate theskull slightly). Theelectric field of TDCSeasily penetrates the

skull to alter neuralcharge and chi flowand induce

neuroplasticity.

Many clinical studiesattest to the value ofTDCS to heal the

mind and body.Although a knowntreatment mode since the 1800s, TDCS seems to be riding a surge of interest since 2000, possibly

because its impact on brain function is better understood. In the PubMed Library database, maintainedby the National Institutes of Health, TDCS clinical studies appear sporadically (less than 2 per year)

until about 2003, when the number of studies begins rising quickly. Over 300 TDCS studies came outin 2012. TDCS has demonstrated clinical effectiveness in treating a variety of mental disorders:depression, anxiety,addiction, eating disorders, post traumatic stress disorder, dementia, and schizophrenia.

Clinical trials are being set up to evaluate other mental disorders like ADHD, bipolar disorder, autismand OCD. The value of TDCS goes beyond healing mental illness. It can restore or enhance cognitivefunction: working memory, attention, learning, mitigate the perception of pain, suppress epileptic

seizures, improve the symptoms of tinnitus and Parkinsons disease and stroke injury.

The Circuit

This project is for asingle-channeltranscranial DCstimulator, the secondof a series of simple

DIY electronic chimodulators (the firstwas a DIYacupuncture laser).The picture above isthe circuit schematic,nothing more than a

current-controlled LED light that turns on when the electrodes touch skin. The sole purpose of the LEDis to indicate that current is flowing. The resistor limits the current to the recommended value of 1 mA.More elaborate stimulators (multi-channel) substitute an active current source for the resistor, which



gives precise current regulation. A single-resistor current limiter operates more reliably than an activecurrent source, and my experience has been that precise current regulation does not seem important.

What is important is the voltage of the power supply. Many TDCS designs on the internet and soldcommercially are powered by a single 9-volt battery, and my experience has been that they do not

work well, even when they are set to the same current output as higher voltage stimulators, possiblybecause the low voltage does not adequately penetrate the skull. My TDCS devices have been mosteffective running on a minimum of power supply of 18 VDC (2 9-volt batteries in series). The powersupplies in this project range from 24 volts to 27 volts: three 9-volt batteries for a total of 27-volts or twoA23 batteries that output 24 volts. The A23 cell stimulator is much more lightweight, but does not lastas long. The maximum voltage tested was 27 volts DC; I have not experimented with higher voltages.

As the batteries wear down, the current will drop too. With a multimeter, periodically check the output

voltage of the stimulator at the electrodes. When the voltage has fallen to 18-volts, replace the batteries.At 18 volts, the current output will fall about 70%, from 1 mA to about 0.7mA. Below 18 volts, theefficacy of stimulator diminishes.

Although these stimulators do not offer the option of adjustable current, I have built others withswitchable resistor values. The table below shows the R values for current outputs of 0.5 mA to 4 mA,based on the formula R = Volts/Current. Standard TDCS maxes out at 2 mA. Some TDCS devices canoutput as much as 4 mA, but clinical studies generally do not set the output this high. In the above

formula, the value of V = V(battery) 2V (subtracting a 2-volt voltage drop for the LED). Other thanthe 1mA R values, the other values have not been tested. Ideally, testing should be done with theelectrodes conducting on skin (like a forearm).

DC Current R Value (24v/27v)

0.5 mA 44K/50K

1 mA 22K/25K

2 mA 11K/12.5K

4 mA 5.5K/6.2K

Construction Tips And Testing

Although the circuit is relatively easy to build, the project does require basic soldering skills. I built the

stimulators inside toothbrush holders. Just about any toothbrush holder can fit two A23 batteries for the24-volt stimulator. Finding one that can hold three 9-volt batteries (27-volt) can be difficult. The holdersfor this project were purchased at a Shopko store in Spokane, Washington for $1.00 each (the blue-

yellow combo was made from purchased all-blue and all-yellow units with the parts later swapped).

The holder must have two small holes at the top to form the strain relief. For the 24-volt version only, asmall plastic candy holder like the Icebreakers round or oval mint packs could serve as a project case.

There is no circuit board; everything is wired point-to-point. The LED, resistor and electrode cable are

assembled first and then inserted into the LED mounting hole drilled into the top of the toothbrushholder. That mounting hole should be a snug fit for the LED, because friction keeps it in place; the

LEDs mounting nut isnt used. All connections are insulated with heatshrink tubing. Drop a piece of



tubing onto one of the

wires. Then solder andlet cool. Slide the

tubing over thesoldered connection.

Then pass a flameunder then tubing to

shrink it.

Always confirm the

actual current outputof the stimulator with

fresh batteries. Thiscircuit built as shown

will output 1 mA DC.

Testing requires acurrent meter

(ammeter) that can read a range of about 10 mA DC. The meter shown in the picture is a digitalmultimeter from Walmart that costs around $25. The testing procedure described below only tests the

maximum current that flows when the electrodes physically touch, that is, not across skin/head contact.To test the current actually flowing between skin points, the ammeter must be connected in series with

one electrode. Note: skin impedance drops over time, so the current reading on skin should slowly

increase to the maximum value. If the skin current is too low, decrease R; if too high, increase R.

The electrodes are an interesting design: sponges mounted on small Command wall hooks, which comein a variety of sizes. Choose the sponges carefully so they dont contain impurities. The electrode

sponges in this project are clean cellulose facial sponges. Rinse thoroughly before use. The other type ofcosmetic sponge made of a latex-free foam seems to contain significant impurities and should be

avoided, because the electricity could decompose the impurities and harm skin. In standard TDCS, theelectrode sponges measure about 4 x 4 cm square and larger. For this project, the sponges must match

the size and outline of the wall hooks. Smaller electrodes concentrate the charge, and larger ones

distribute it. In standard TDCS, the electrodes are strapped to the head and scalp; a treatment sessioncan last over 20 minutes and is generally given once a week or month in a clinical setting. The average

length of a session with my stimulator is meant to be about 5 minutes or less, given one or more times aday, as needed. The shorter session time allows the electrodes to be held in place with hands.

This article does not offer a guide to electrode placement, because the topic is complex and because

study of TDCS is ongoing. Instead, placement suggestions can be found in the published studies and

by consulting acupuncture charts. Clinical studies generally locate the electrodes over the area of thebrain known to affect the mental condition. One alternative is to apply TDCS to acupoints or

acupuncture points. Acupoints, identified and mapped by trial-and-error, have been studied forhundreds of years. The electrode sponges distribute an electric charge over a much wider area than the

point-to-point contact of acupuncture needles. Yet, acupressure, which stimulates acupoints with thetips of fingers, also applies force over a wide area. The example below shows how to apply TDCS based

on modern medicine by researching brain function.



Instructions For Building A Transcranial DC Stimulator

Parts (catalog numbers are Radio Shack):

36V version

1 Red LED assembly (RS 276-0068)3 9V battery clips (RS 270 0325)

1 25K ohm, 1/8 watt resistor or 22K ohms + 2.2K ohms (RS 271-1339 and 271-1325)3 9V batteries

Heatshrink Tubing (RS 278-1610)1 toothbrush carrier (195 x 29 x 23 mm see text)

2 Command Designer Hooks (small)

1 cellulose facial sponge, 6mm (0.25 inch) thick10 feet 24-gauge 2-conductor cable (RS 278-1301)

24V version

1 Red LED assembly (RS 276-0068)

2 A23 battery holders (available on Amazon.com)1 22K ohm, 1/8 watt resistor (RS 271-1339)

2 A23 (12V) batteries

Heatshrink Tubing (RS 278-1610)1 toothbrush carrier (205 x 27 x 20mm see text)

2 Command Designer Hooks (small)1 cellulose facial sponge, 6mm (0.25 inch) thick

10 feet 24-gauge 2-conductor cable (RS 278-1301)

Stimulator Method:



1. Top of toothbrush

holder should havetwo vent holes. If one

or both are missing,drill to make a set of

holes at least 1/8-inch

diameter each. Thesewill be part of thestrain relief for the

electronic cable.

2. Locate the desiredposition for mounting

the LED on the tophalf of the toothbrushholder. Lay masking

tape over the positionand mark 3/8-inchhole for drilling. Drillthe hole and test fit the LED.

3. If R will be two resistors, solder them in series. Solder the current resistor to anode lead of the LED.The anode is the longer lead. Test the assembly with a 9-volt battery by touching the other lead of the

resisot to the + terminal and the free lead of the LED to the minus terminal. It should light.

4. Cut a length (about



4. Cut a length (about36) of twin lead forthe electrode cable.

Designate one lead tobe the positive and theother negative. (Tip:examine the cable for

a marking thatdistinguishes theleads.) Strip about 1/2

inch of insulationfrom the wires on oneend. Solder thepositive wire to the

free lead on the LED.Set aside.

5. Snake the free endof the electrode cablethrough the LEDmounting hole, and

out through a hole atthe top. Loop it backin and out the other

hole, forming a singleknot as a strain relief.

6. Assemble the

battery pack: for the24-volt version, soldertwo A23 cell holders

in series, red to black.Insert A23 batteriesinto the holders. Withthe voltmeter, confirm

the pack outputs 24volts.

To make the 27-voltpack, solder three 9Vbattery clips in series (red to black). Attach 9-volt batteries to the clips and confirm the output voltageof 27-volts. Test fit battery pack in the bottom half of the toothbrush holder.

7. Solder the positive (red) lead of the battery pack to the free end of the resistor. Solder the negative(black) lead of the battery pack to the negative wire of the electrode cable.



8. Put the batterypack in the bottom

half of the toothbrushholder and close withthe top half.

9. Strip 1-1/2 inch ofinsulation off each

wire at the other endof the electrode cable.Twist the strands of

each wire together.Cut two 1/2-inchlengths of heatshrink

tubing, one color toidentify the positivewire and anothercolor for the negative

wire. Slide the tubingover their matchingwires.

Form the end of eachelectrode wire into aloop and solder in

place. Tin the loopwith solder. Slide theheatshrink tubing upjust behind the loops

and shrink in place.

Touch the two loops

and the LED shouldlight. To test thecurrent output of thestimulator, set the

multimeter to readDC current in the2mA or 20mA range.

Connect the meter tothe electrode loops,positive (red) meter topositive TDCS wire

and negative (black)



meter to negative

TDCS wire. The LEDshould light, and themeter should readabout 1mA (the

displays in thepictures above readwithin 10% of 1mA).

To test the voltageoutput of thestimulator, set the

multimeter to readDC voltage in the200VDC range.

Connect the meter tothe electrode loops asbefore, positive (red)meter to positive

TDCS wire andnegative (black) meterto negative TDCS

wire. The metershould read thebattery voltage minusapprox. 2V for the

LED. In the pictureabove, the meterreads 26.3 VDC,

because the batterypack of three 9Vbatteries actuallymeasures about

28VDC.

10. To make the

electrodes: from theback of the hooks,remove the tabs forthe adhesive mounting strip by sliding them down and off. Fill the back cavity of the hooks with

crumpled aluminum foil to create a level surface. Lay a cellulose sponge on a table and trace theoutside edge of the hook onto the sponge twice. Cut out the two electrode sponges. Position a sponge onthe back of each hook and secure with a small clean rubber band.

11. To connect the



11. To connect the

electrodes, remove therubber band from theelectrode and lift up

the aluminum foil.Place a wire loop intothe back of the hook.

Reassemble andsecure the electrodewith a small rubberband.

Operation:

General Procedure

(current flows fromthe anode + to thecathode -):

1. Remove the spongefrom the electrode.Moisten the sponges

with water andsqueeze out all excess.Reassemble the

electrode assemblyand secure with therubber band.

2. a. To stimulate acranial point, applythe anodic (+)electrode to the target

area and the reference(-) electrode to theshoulder area on the

opposite side(contralateral deltoid).

b. To sedate or calm a

cranial point, applythe cathodic (-) electrode to the target area and the reference (+) electrode to the shoulder area on theopposite side (contralateral deltoid).

c. To re-polarize or redirect a path in the brain, first determine where on the path the brain will bestimulated and where it will be sedated. Then apply the anodal (+) electrode to the area to be stimulatedand the cathodal (-) electrode to the area to be sedated. Current will flow from the anode to the cathode.



3. Moisten theelectrode points on theskin with a water-

based lubricant likeKY Jelly (optional).Place the electrodes inposition and hold in

place for at least 2-1/2minutes or as long asdesired. If

stimulating/sedatingsymmetrical points,locate the mirror point

on the opposite side ofthe head and repeatstep 2.

4. When done, rinsesponges and let dry.

Treating Anxiety Or

Depression: A TDCSExample

An excess ordeficiency of activity

in the temporal lobeof the brain can resultin anxiety ordepression. (See, e.g.,

Amen, Daniel &Routh, Lisa, HealingAnxiety and

Depression, NewYork: G.P. Putnam, c.2003, p. 71.) Foranxiety, apply

cathodic TDCS to thetemporal lobe to calmexcitability. The

picture above showsthe negative electrodepositioned over the temporal lobe area just behind the ears. The reference electrode (positive) goes to thebase of the neck on the opposite side. Allow the current to run for 2 to 3 minutes. Then apply cathodic



TDCS to the temporallobe on the other side

of the head (and movethe reference electrodeto the other side of theneck). Total treatmenttime: 4 to 6 minutes.

Repeat as necessarythroughout the day.

To treat depression,apply anodic TDCS tothe temporal lobe in asimilar manner (thepositive electrode goes

behind the ears andthe negative electrodegoes to the base of theneck on the oppositeside). For anxiety ordepression, there

should be animmediateimprovement aftertreatment. The effectis cumulative, socontinue dailytreatment for up to a

month and maintainas needed.

Not all anxiety ordepression originatesin the temporal lobe.If the treatments dontseem to improve the

condition, try adifferent placementover the temporallobe. Finally, researchother areas of the brain that could impact the condition and try relocating the active electrode there.

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