The BIG Blinky -

The BIG Blinky -
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So far our arduino projects interfaced only to low voltage circuits.
However a large number of useful control circuits involve interfacing to 230v ac mains.

We start with a simple circuit using a relay and the standard blinky program. But instead of blinking a LED, we blink a relay which turns on and off a 230Vac night lamp.
Here is the schematic


What is the weird symbol to the right of 1N4001?

We power our simple circuit from arduino Vin. Vin is the voltage we feed to the arduino DC jack, in this case 12 Vdc.
We did a quick hack by assembling the components on a vero board.
Now that it works, @ravi31 will make a pcb on kicad. Then fabricate it by hand, before finally handing over the design - if we mange to avoid goofups (else rinse and repeat) - a professional pcb manufacturer.
We will automate the lights in our maker lab using this board.

Will we require sensors too?

We could replace the relay with a Triac and an opto coupler.
Why should we use an opto coupler? ([Hint:] :smiling_imp:)(How-do-birds-sit-on-high-voltage-power-lines-without-getting-electrocuted)

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Extending from this thought process, although not this particular fork (for mains voltage motors) several very useful technologies for accessibility were discussed in another conversation. I’m condensing that here.

  1. Given that hand motion can be easily used to trigger a motor (not necessarily 230VAC), two motors with perpendicular axes can be used, with sufficiently weighted flywheels, to counter the condition known as essential tremor. A device using such a design has already been built, and with some luck, I’ll be able to locate and display the descriptive video here. Ok, so I couldn’t find it, but I’ll try and upload it directly in another post.

  2. It is fairly straightforward to feed a Braille translation of any text, using a smartphone (apps are readily available in the phone software stores). Which means the text could originate from a text conversation, or by text conversion from speech, or be tapped by somebody in direct conversation with the user, but who doesn’t know how to use sign language. While people with visual impairments might be able to hear a conversation within earshot, this is not so for the deafblind. Apart from visual and deafblind impaired persons, Braille (and, much simpler devices, Morse and TapToTalk) is also handy for persons with motor impairments, who cannot use ordinary screen displays and keyboards.

A set of low voltage terminals in a grid, or a grid of tiny solenoids, could be used to create a single character (or more) refreshable display worn as a glove or a wristband. Unlike a fingertip sensing display, which needs a large throw for the fingertip to sense the shape, the back of the hand, from the knuckles to the forearm, is much more sensitive. A lot of work has been done at NCBS Bengaluru for creating a touch pad for the tongue, which is the most sensitive accessible part of the body, but this might be beyond the capabilities of a tinkering project.

  1. A tactile keyboard, on the other hand, very useful for persons with fine motor impairments, might use regular gross hand movements as specific triggers for inputs to a screen displaying device. eLocutor, the screen display tool, was developed for a single switch (with 3 positions: on, off and hold). It could be reengineered for a modern phone.
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Is there a simple way to offset a second paragraph in a series of numbered bullets? Sometimes, for clarity, it really helps to break continuing matter into 2 or more paragraphs, while retaining the thread of simple bulleted numbers.

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The composer supports MardDown. Markdown Cheatsheet · adam-p/markdown-here Wiki · GitHub

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what could be the alternate of lipo batteries for robotic project

Wired power.
Super capacitor bank.
Lead acid battery
NiCd battery
IC gas engine driving a generator.

A large enough solar panel can also be used.
The australia solar car race runs on solar from Darwin to Adelaide. Really coool machines
https://www.worldsolarchallenge.org/