2Wire (I2C) From Blocks of Light on an LCD Screen

Description

"Here is a crazy idea for interfacing web pages to the real world. Imagine an old SmartPhone sitting in a cradle on a robot or other hardware device. On the phones browser, a web page is pulled up with a Javascript program running that is changing two blocks on the screen from black to white. One block is the clock line, the other is data, and they transmit 2wire (Unidirectional I2C) data. In the cradle, at the bottom of the phones screen, a pair of optical sensors convert the light level into voltages in two wires which then connect to any I2C device (e.g. a servo controller^, D2A, uC, whatever).

Now you have a Javascript controlled robot with wifi connection, maybe camera, screen space for faces or whatever, audio, etc... And optocoupled so there is no danger of frying the phone. No need to root the phone, no need for any apps, no development environment other than a text editor.

Can't post Javascript here, so go to the link and press the "Send" button to see the blink'n'light

Files

Optical SDA SCL.zip

Eagle files for circuit from Conrad.

application/x-zip-compressed - 155.78 kB - 12/28/2015 at 17:36

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Project Logs

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This solution has found a problem
James Newton • 04/05/2022 at 19:01 • 0 comments

This idea is very much a solution in search of a problem, and now there is a problem that is worthy of being solved this way. A robot that is cheap as dirt, but as smart as the average SmartPhone, with all the phones sensors available to detect collisions and tipping (accelerometer) and direction (compass) and position (GPS) and recognize objects and avoid obstacles (camera, possibly with the laser line structured light trick and with cloud services or even vision in the browser via OpenCV.js) all while retaining the WiFi connection to the net for true teleoperation. More about that here:

https://hackaday.io/project/184720-web-smart-phone-screen-blink-bot
(be sure to read the detail section)
New code, support for shift registers
James Newton • 02/02/2022 at 18:10 • 0 comments
Updated versions of this code are also available, using better methods and also supporting shift registers.
- https://stackblitz.com/edit/js-4pcwal?file=index.html Modern version for browsers supporting async / await. It also supports a 3rd block for latching the data into a shift register.
- https://stackblitz.com/edit/js-kxazxy?file=index.html A version written with setInterval and a state machine. Runs in old browsers. Latch support is available, but must be set with an option selection.
These are untested and I would very much like your feedback on them. If you see bugs, please let me know. The silence on this project has kept me from devoting any time to it, but please know that if you ask, I will respond and make corrections, etc...

I'd really like to work on a design for a little board to interface between either a shift register or a microcontroller. My idea is that perhaps one board can be made to serve both functions. e.g. You populate part of the board for I2C, and you populate a different part for a shift register.

The other option is to do two separate boards, in which case I would do the I2C to uC version first. It would be something like my RC Servo to uC adapter board:
https://hackaday.io/project/181972-rc-servo-adapter
but with locations to mount the electronics and 2 light sensors, either directly to the PCB or via wires. (note to self, remember to include strain relief holes. I always forget those).

If a final circuit for a shift register is tested, then I'll try to include a 3rd sensor and use one edge to pinout for a shift register chip.
Another schematic
James Newton • 02/02/2022 at 18:06 • 0 comments

Juergen Pintaske from Facebook also made and tested a version of this. (video is facebook only sadly) Here is the schematic he used:

he is very interested in a version with 3 channels for shift registers.
Got a circuit board to test with!
James Newton • 02/19/2015 at 20:52 • 0 comments

My friend Conrad soldered up a permanent version of the breadboarded circuit and gave it to me. Next is hooking it up to an Arduino and testing the transmission of data for accuracy and speed.

View all 4 project logs

Discussions

muzz.7044 wrote 07/18/2023 at 11:57

For example, if someone says, "As stated on page 10 of the report," it means that the specific information being discussed can be found on the tenth page of the mentioned report. https://techzone-agency.com/

Are you sure? yes | no

muzz.7044 wrote 07/18/2023 at 11:56

For example, if someone says, "As stated on page 10 of the report," it means that the specific information being discussed can be found on the tenth page of the mentioned report.

Are you sure? yes | no

muzz.7044 wrote 07/17/2023 at 10:57

nformation effectively, and ensuring proper HTML markup, on-page optimization aims to make the webpage more accessible, relevant, and appealing to both search engines and https://techzone-agency.com/

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Ken Yap wrote 07/27/2019 at 00:41

Morse code was designed for humans to decode. You could probably use a better and more efficient (not that it matters in this use case) encoding such as those used in remote controls and throw in some error detection/correction as well which is more salient.

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James Newton wrote 07/27/2019 at 02:23

The trick is finding one that supports wide variations in speed. Any suggestions?

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Ken Yap wrote 07/27/2019 at 02:45

You could always start off with a sync pattern. Also look at how barcode scanners do it, those have to adapt to scan speeds too.

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James Newton wrote 07/27/2019 at 03:54

Maybe Manchester encoding so the clock is in there with the data:
http://techref.massmind.org/Techref/io/manchester.htm

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James Newton wrote 07/26/2019 at 22:48

Here's an idea for going the other way (getting data into a cell phone from an LED on a device)

Let's say you setup your IOT device (ESP, whatever) to talk to your router at your home. Now you need to figure out what IP address your home router assigned. Some of us can log into the router to see the DHCP table, but some routers are locked down, etc... There are programs that will scan the IP space, (e.g. FING) but another option is to somehow communicate the value from the bot.

Ido and I were talking about doing this. I remembered that there was a javascript page that could decode morse code:
https://www.bennadel.com/resources/demo/morse_code/
https://www.bennadel.com/blog/2267-decoding-morse-code-with-javascript.htm

Take the keyboard events off that and add processing from the camera:
https://googlechrome.github.io/samples/image-capture/grab-frame-take-photo.html

Accessing the pixels in the picture isn't hard, and you can do a threshold to see if the picture is overall bright (LED on) or dark (LED off).
https://github.com/JamesNewton/AdvancedRoboticsWithJavascript/wiki#image-subtraction-in-a-smartphone-browser

Put that on a public web page (must have HTTPS, not HTTP) and then users can go to the web page, allow access to the camera, hold the camera over the robot, get the web URL decoded, and then click on it to connect directly to the robot!

Users don't even need to know that it's using morse code. But it's also sort of cool that it could decode any message.

Are you sure? yes | no

PointyOintment wrote 02/03/2015 at 22:55

Are you sure? yes | no

James Newton wrote 02/04/2015 at 00:09

Are you sure? yes | no

2Wire (I2C) From Blocks of Light on an LCD Screen

Description

Files

Optical SDA SCL.zip

Project Logs

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This solution has found a problem

New code, support for shift registers

Another schematic

Got a circuit board to test with!

Discussions

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2Wire (I2C) From Blocks of Light on an LCD Screen

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