How would you go about building this?

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TheRyad

Joined Jun 4, 2009
7
Thanks for the clarification, Propaganda. You have been very helpful.

THE_RB, I am very encouraged by the price and your statement that it would easily fit into a bottle cap size. Is a PCB not required?

Zenoc, I really the idea of the dual purpose for the IR. Do you also think it can fit into such a small size at that price?

With regards to using IR, I am assuming it has to be always on. Given that this has to remain active for 3 months, is a 3V battery still sufficient?

CDrive, thanks for that link!

I am going to bring in a few ideas from other sources and I am really interested on hearing your thoughts about them.

- Basic Stamp instead of PIC
- Electronic compass as sensor
- Accelerometer as sensor
- Mercury drop switch with opposed contacts

Please keep in mind the importance of size and cost.

Thanks guys!
 

THE_RB

Joined Feb 11, 2008
5,438
I think all of those parts will increase costs. Apart from the mercury switch which is not gonna work very well anyway.

Yes you will need a PCB. A bottlecap sized one. :)

No the IR does not need to be on all the time. The door open event is SLOW by PIC terms, so you can pulse the IR sender every 0.5 second for a very short pulse. Any door open periods will be at least 1 second.

Like Zenock says you can omit the button and use the IR receiver to start the transmission, BUT then you need a receiving device that has both send and receive. And it may use more power as you will need to detect IR reception during your main operating phase. Personally i'd be tempted to go for the button, it opens up possibilities, ie; using the device in different run modes etc.
 

Zenock

Joined Jun 1, 2009
36
Like Zenock says you can omit the button and use the IR receiver to start the transmission, BUT then you need a receiving device that has both send and receive. And it may use more power as you will need to detect IR reception during your main operating phase. Personally i'd be tempted to go for the button, it opens up possibilities, ie; using the device in different run modes etc.
That's true. I was thinking of size... eliminate parts, size goes down. ;-)
Bottlesize PCB will be inexpensive if you etch it yourself. If you do decide to dual purpose the IR, you could use a laptop for the send receive device. Or you could remove the device from the door and set it next to a desk top with ir transmitter receiver hooked to serial port. Cost of building one of these is trivial.

Here's a receiver...
http://www.best-microcontroller-projects.com/infrared-receiver.html

Here's a transmitter...
http://jap.hu/electronic/irtx_pic.html

These are just from quick googles, I haven't even read them completely. I've built a serial transmitter/receiver myself so it really isn't that difficult or expensive since I'm just about the dumbest and cheapest person I know.

Z
 

CDRIVE

Joined Jul 1, 2008
2,219
I think a lot of time could be saved here if the OP was more up front about what his intentions really are. It became fairly obvious to me, early on, that he perceives a marketable use for his idea. I don't believe this is a one off project. That's why cost and size are so important to him. Right from the get go the OP stated that he is not a Tech or Engineer and has very little electronics education.

If what I said rings true, then the OP is (in my opinion) going about this all wrong. In my many years in this industry I've made some observations and some conclusions. The most paramount of these are that Techs and Engineers make crappy salesmen. They live in their own little world of the current project before them. There are many talented Techies out there that can design damn near anything but don't have the Salesman in them to do anything with it and this includes ME! Talk to them about the minutia of cost and sales and you will see his eyes glaze over.

The successful launch of a product requires at least three elements:

(1) The go getter salesman type that can make things happen. A guy that can open doors and make contacts. This, I believe, would be the OP.
(2) The Electron Head that will design it.
(4) The Money Man that will float the project from R&D to marketing.

The Electron Head has no interest in stealing your idea. He just wants to design it and salivate over his next challenge. The Financier also has no interest in stealing your concept. He just wants to put his money into a profitable endeavor knowing that there is a (make it happen) guy at the helm.

In the end you can't keep it all. The three elements, maybe a corporation, must work out your piece of the pie. The Electron Head will gladly work with the promise of being a major stock holder as long as you supply him with the materials and equipment he needs to complete the job.

Once the prototype is finished then you're going to have to decide whether you're going to off shore (the death of us all) the manufacturing or not.
 

CDRIVE

Joined Jul 1, 2008
2,219
So can you take a design provided to you from a public forum and patent it?

Just wondering?

Z
There are different types of patents and you don't have to be the creator of the item to own the patent. As a general rule you can't patent technology that is considered common knowledge to your peers. There are also patents that protect how the product is packaged and has little to do with the technology within. The Clapper is probably a good example, as there isn't and wasn't anything revolutionary in that box.

The Intermittent Windshield Wiper was a classic court battle that demonstrates how a guy in a black robe, who understood nothing about electronics, adjudicated in favor of the patentee. Like the Clapper, the transistor timer circuit design was common knowledge among his peers. Hell, it was basically an astable oscillator! Yes, a common Flip Flop! Hardly unknown to his peers, as the man was an EE. At best, he should have only been able to secure an Applications patent by arguing that, though it's not new technology, it's application in windshield wipers was a first.

By the way... No, I didn't see the movie but I did read about the court case.
 
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