We are getting many genuine requests from elderly readers who are suffering from different health related problems and one very painful condition among them is Dry Mouth also called Xerostomia.
Real Life Dry Mouth Problem
One of our respected readers from South Africa who is now 76 years old shared his real life suffering with us. He explained that due to Dry Mouth he is not able to enjoy even simple things like lemon tea coca cola soft food or even peaceful sleep at night.
During sleep when breathing happens through mouth then the tongue becomes fully dry and sticks to the mouth roof and this creates panic and sleepless nights. This problem becomes worse during cold or damp weather and affects the full body condition.
Some medical research papers from UK and India mention that low frequency TENS stimulation applied near the Parotid Gland area of the face can help stimulate saliva secretion.
The Parotid Gland is one of the major salivary glands located on the side of the face near the jaw and ear region.
Based on this information and the reader request I have designed the below given very simple adjustable TENS signal generator circuit using IC 555 which can be safely experimented with under proper care.
Audio/Video Representation
What This Circuit Is Intended For
This circuit is not a medical device and we are not claiming any guaranteed cure. This circuit is only an experimental low power TENS signal generator meant for learning and careful personal experimentation.
If someone has serious medical condition then doctor guidance is always required. This project is shared purely to help readers understand how low frequency stimulation signals can be generated using simple electronic parts.
Basic Working Principle
The circuit is based on IC 555 configured in astable multivibrator mode. In this mode the IC continuously generates ON and OFF pulses at its output pin 3.
The frequency of these pulses can be adjusted from very slow pulses like 2 Hz 4 Hz up to higher values like 50 Hz 80 Hz or even more.
These frequency ranges are commonly mentioned in research papers related to TENS therapy.
By adjusting the pots provided in the circuit the pulse width and frequency can be controlled so that different stimulation patterns can be tested carefully.
Power Supply Section
The circuit works with a simple 9V battery. This keeps the circuit isolated from mains and makes it safer for experimentation.
The 9V supply is connected to pin 8 and pin 4 of the IC 555 through a small 1k resistor which helps in limiting current and stabilizing the supply.
Frequency Control Section
The frequency generation network is formed using a 1M pot a 10k pot two 1N4148 diodes and a timing capacitor connected to pins 2 6 and 7 of the IC.
The diodes allow separate control of charge and discharge paths which gives better frequency adjustment range.
The 1M pot allows wide frequency variation from very slow pulses to faster pulses.
The 10k pot helps in fine tuning the frequency so that exact low frequencies like 2 Hz 4 Hz or mid range frequencies like 50 Hz can be obtained.
The 10nF capacitor connected to pin 2 and pin 6 determines the base timing and can be changed if required for other frequency ranges.
Output Pulse Conditioning
The output pulses appear at pin 3 of the IC. From here the signal is passed through a 4.7k preset which acts as an output intensity control.
This is very important because TENS stimulation must always start from the lowest possible intensity and slowly increased only if comfortable.
After the preset a 1uF non polar capacitor is used for AC coupling. This capacitor blocks DC and allows only the pulses to pass to the TENS pads. This is essential for safety and comfort.
A 1M resistor is connected to ground after the capacitor to ensure proper discharge and stable output reference.
TENS Pad Connection
Two TENS conduction pads are connected at the output. One pad goes to the pulse output and the other pad goes to 0V ground.
These pads must be attached only on clean skin area near the Parotid Gland region on the side of the face. Placement must be gentle and pressure should not be applied.
Always ensure skin is clean and dry before attaching pads.
How This Circuit May Help
When low frequency pulses are applied near the Parotid Gland then it may stimulate the salivary gland nerves.
This stimulation can encourage saliva secretion which may help in reducing dry mouth sensation during rest or sleep hours.
Some users may find benefit at very low frequencies like 2 Hz or 4 Hz while others may feel better at 50 Hz or 80 Hz. This varies from person to person.
Important Safety Notes
This circuit must be used with extreme caution. Always start with minimum intensity. Never use while driving or operating machines.
Do not use if you have pacemaker heart condition epilepsy or any serious neurological issue.
If any discomfort pain or burning sensation is felt then immediately stop using the circuit.
This project is meant only for educated experimentation and learning purpose.
Final Words
Dry Mouth Xerostomia is a very difficult condition and affects quality of life badly especially for elderly people.
If simple electronic experimentation can provide even small relief then it is worth exploring carefully.
We sincerely hope this circuit explanation helps readers understand how a basic low frequency TENS generator can be built using IC 555.
If any reader has additional experience suggestions or improvements related to this topic then please share in comments so that others suffering from similar problem can benefit.
We wish all readers good health peace and restful sleep.