IR Microcode/Microdot and Shape Scanner/Reader, and Adjustable Bluetooth ranges.

Hey guys.

Newbie stuck on this...

I need some type of Infrared Micro Scanner/Reader to read microcodes and a triangle shape, possibly in a microdot, all invisibly printed with an IR inkjet over sections of paper that already was printed up previously in the visible spectrum with a laser jet (like how IR ink is used for security watermarks).
I need to make it as compact as possible and on a tight budget. So a laser scanner and regular IR micro camera are out. Also this microcode or microdot Scanner/Reader will not be moving over the paper. Just placed. The microcode making up the possible microdot will probably be a bar code unless I find a way to make optical recognition of real digits work.
I planned to have it controled via an Arduino Nano on watch batteries. The microcode and position of the triangle shape will be sent to a Bluetooth LE Arduino module, setup to eventually get that data back to an app to interpret the microcode and triangle facing.

Any recommendations on how to read the IR code and triangle shape? The IR Scanner/Reader will only be a few milimeters away from the microcode and triangle, and the edges of this compact project box holding the electronics and batteries will all have rubber strips on them leaving those few milimeters in complete darkness (no visible light, not that it matters for IR). UV will work too if that makes any idea differences.

I have seen a similar concept setup with out a laser scanner or regular IR microcamera, but don't know how they built the IR reader part.

An example of it would be found between 1:25 and 2:20 of this YouTube video...

With an image of the Stylus seen here...

On a seperate but related note... How do I setup the Bluetooth LE to work at various distances less then its max normal distance? These distance settings would be controlled by a multi position slidding dip switch, intentionally limiting the range of the actual Bluetooth channel. Because very little data will be transmitted from the project box back to the hardware running the app, reduced bandwidth, in addition to reduced range, is not a big issue.

Thank you in advance for any feedback/ideas.

I imagine this would require a lot of R&D $$$ unless you use existing tech.


Its not clear to me that the ink is 'Infrared', just the camera in the Pen backed up by local on-board proccesing.

My guess would be that it may be better to resell/use an existing pen & printing solutions.

Regarding BT range: range will be proportional to tx power and the location (indoors/outdoors/Line of Sight walls etc). However, if a user at the other end has a very good antenna the range will be further than you think.
You could attempt this by accessing signal strength (RSSI) of the other party & blocking the connection unless very strong RSSI is reported. Access to RSSI values are chipset dependent. In this scenario you could run with a poor antenna on your side and only connect to other devices with very strong RSSI values. You may also be able to access tx power settings, which would be another tool.

Example of such a pen: Livescribe :: Never Miss A Word - Livescribe – Livescribe Inc. (US)

I can't imagine being able to build something like this without the R&D $$$ that AnalysIR mentioned. A camera, optics, ARM processor, bluetooth, and battery management in something that size? No DIYer could pull that off.