Highly accomplished Yogis can read what's going on in other's minds. This they can achieve by a process called Samyama. Here Yantras are not required.
This is a Yogic Siddhi and thus not a sin. Even deities know our thoughts and are witnesses of all our actions.
Patanjali Yoga Sutras Vibhooti Pada chapter has the following sutra:
In my personal experience I have seen several types of yantras used by Sri Vaishnavas and in Pancharathra/Vaikhanasa temples. It would be a futile attempt to list them all for the reasons I will outline below.
A yantra is a physical manifestation of a mantra. The text of the mantra itself is etched onto a metal sheet (typically copper/silver/gold/panchaloha)...
True. Chakra is a pattern that holds energy in it. Particularly Shri chakra yantra is made with a specific metal (I believe its copper). The dot is the centre of this yantra is called 'bindu' and this is where all its energy is stored. This yantra holds and emits positive energy when invoked by chanting special mantras.These mantras contain beeja aksharas. ...
You can venerate the yantra with simple kumkum or flowers or rice grain etc.
You can chant parashurAma gayatri mantra
परशुराम गायत्री मंत्र :-
ॐ जामदग्न्याय विद्महे महावीराय धीमहि ! तन्न: परशुराम: प्रचोदयात !
‘ॐ रां रां ॐ रां रां ॐ परशुहस्ताय नम:
or simple naama mantra.
Here is a stotra which can be used while worshiping his ...
I am adding my own partial answer based on information found on Astrojyoti.com
According to the author of the above article, the correct color fillings for Sri Yantra has been given in various Scriptures. But the author quotes only the Mantra Mahodadhi.
For quite sometime I have been observing the many multi coloured sri
yantra pictures published in ...
The designs of the Yantras all come from the Tantras and Lord Shiva is the creator. That is basically how they have come to being.
In Mahanirvana Tantra's 1st Chapter the Mother Goddess says:
By Thee also have been composed for the good and liberation of men the Tantras, a mass of Agamas and Nigamas, which bestow both enjoyment
and liberation, ...
You can find detailed pooja process and yantra pooja of Sri Ganesha in texts like mantra mahodadhi.
You can check the second chapter starting from page 48.
It also has nyasa and other necessary details for the pooja. Nevertheless, one should be initiated before taking up these poojas and upasanas.
What exactly is the purpose of this yantra?
First, we need to know what the purpose of a Yantra in general is.
In Hinduism, although the God is essentially stated to be Nirguna, but Saguna worship is mainly recommended, as worshipping the form-less is basically an impossible task.
And, for that purpose, symbols (Pratik) are introduced in various ...
The following image is a correct form of Sri Yantra. But some other forms are also correct.
Quoting from Astrojyoti.com, from where the image is taken:
Shree Chakra pooja or Yantra Pooja is the worship of a deity in a
diagrammatic form. This type of worship exists in a lot of the other
parts of the world also. To enjoy the benefits of Shri Chakra ...