idea: "green" blinky throwy

[FrankBuss]

I read about LED throwies and blinkies. If I combine this with a solar cell, could this be a successful Kickstarter campaign? Unlike the usual throwy it could blink for decades at night and charge at day (I guess the solar cell would stop working or degrade first after some time).

[ataradov]

I think the main point of those devices is cheapness and disposable-like nature. With solar battery you will need rechargeable battery and charging circuits. All that will make design bulky and expensive.

I doubt it will be successful unless you mange to market it very well.

[FrankBuss]

I could use a SuperCap instead of a battery, this would simplify the design. If the on-time of the blinking duty cycle is short, it should last a night even with a small capacitor.

But you are right, would be more bulky than the classic throwy. It would be a product somewhere between the big solar cell garden lamps and a throwy, but still small, maybe a 4 cm ball.

[matseng]

Just add a blink circuit to this $0.83 unit and you're golden :-)
http://www.aliexpress.com/item/New-2015-Mini-Portable-Solar-Power-Black-3LED-Light-Keychain-Torch-Flashlight/32401698674.html

[FrankBuss]

Just add a blink circuit to this $0.83 unit and you're golden :-)
http://www.aliexpress.com/item/New-2015-Mini-Portable-Solar-Power-Black-3LED-Light-Keychain-Torch-Flashlight/32401698674.html

You can even get it for $0.45
http://www.alibaba.com/product-detail/2015-New-Mini-Portable-Solar-Power_60281777182.html
How can they produce it so cheap? I estimated the price for the parts for my device with SuperCap, solar cell, a small PIC microcontroller, step-up IC and passive parts would be at least $4, and then it needs a nice case, the magnet and manufacturing costs. But thanks for the link, I'll buy some and take a look what's inside.

What do you think about an extended version, with bluetooth low energy? Could be a solar powered Bluetooth iBeacon, very useful for geocaching as well.

[ataradov]

How can they produce it so cheap?

I believe there is a video teardown of one of those on YouTube (possibly by bigclivedotcom). Basically, the cheapest ones have fake solar cell and a regular battery, it works until battery lasts and then that's it. But who will bother dealing with some sketchy seller in China for $0.45?

What do you think about an extended version, with bluetooth low energy? Could be a solar powered Bluetooth iBeacon, very useful for geocaching as well.

It is gimmicky, so all depends on the marketing. If you can find the right crowd, it will get funded.

I personally not only don't "fell" that device, I can't even see a type of person who might.

[ataradov]

Yes, here is the video:

[FrankBuss]

Interesting video. The solar cell even worked, but they saved some cents by omitting the diode and the rechargable battery. But it makes the device more safe, because the battery can't be overcharged

And too bad, there is already a solar cell iBeacon:
http://www.alibaba.com/product-detail/solar-cell-ibeacon-with-power-switch_1635290817.html?spm=a2700.7724857.29.10.9Qdiw0
Looks like it uses the same case as the other product.

[ataradov]

As Chris pointed out in the last Amp Hour, don't be discouraged by existing implementations of your idea. Because basically everything already exists.

You can't compete with China on price, don't even try. But you can compete on quality. That Chinese plastic case won't do for geocaching, that can be a selling point. Of course, given the popularity of the game, it is highly likely that all that equipment exists already and it is going to be a hard sell.

[FrankBuss]

Right, quality and additional features might be a selling point. I think I could add a SD card slot and a temperature sensor, then it could be solar powered, long term temperature logger with Bluetooth connectivity.

Or something for The Things Network. It was mentioned in an Amp Hour episode and looks really cool. 10 km range with one EUR 200 server device. As a client, they sell an Arduino shield for EUR 40 and the project got funded for EUR 300k. I'm sure I can create a cheaper client.

[Brutte]

Because basically everything already exists.

I have heard that many times.

LEDs emit light when subjected to current flow but these also work as PV cells when subjected to light. You could design a crystal-clear, custom shape, lensed LED for that. This way you could kill two birds with one ehh... LED to reduce the BOM.

You could also generate electrical energy by using thermoelectric effect (hint for your temperature logger).
For tests, take two pieces of different metals (like steel paper clip and copper wire), tie/solder two ends and connect a voltmeter to the other free ends. Length of wires does not matter. Then apply temperature gradient (for example heat tied ends and let the other ends cool). You could stack that up to get just enough voltage to run a tiny boost converter. The efficiency of conversion might be poor (0,1%) but if the heat is free and uses cheap BOM then nobody cares when it does the job..

[Kilrah]

To me the whole purpose / attractivity of these things lies in their short life, you get them at a party, wear them proudly with your friends during the night, then forget about them. IMO the "durability" concept would not pass the first real world test i.e. someone getting them once to try because it's new and trendy but who would quickly realise it's nothing but a waste of the extra $x they cost vs normal ones.