First off, thanks for giving the opportunity to take part at this contest. I hope my project will inspire you.
The Idea came to me when I was in a crowded bus station, without any battery left on my phone and trying to find the charging cable of my power bank. Would it be great to have a charging dock in your bag without any fuss?
Check out the build video:
Phase One: The power bank
I bought a cheap power bank from eBay, it was rated at 80000 mAh (?) and had solar charging. I unscrewed the case, desoldered the charging leds (small blue leds), the so called flashlight led and the solar panel.
I took two blue leds and soldered to extension cords. These leds are designed for notifying when the receiver is charging or when the battery is getting power from solar panel.
Also, leds notify whats the battery status, if two leds are on the battery is full, and when the battery discharge, leds turn off.
After this I soldered a longer cable on the solar panel.
Phase two - The Bag:
On the table is the coolest bag I could found, my notebook bag, and it is mandatory to have many pockets or else one will have to sew some for the power bank protection and wireless transmitter. I drilled 3 holes designed for the two leds and solar panel cable.
It's time for assembly! I mounted the leds and the solar panel on the front of the bag and then I solder everything on the power bank. For mounting the leds I used hot glue and for the solar panel I tried double stick tape but didn't worked so good and I went with hot glue as well.
I have to say, cable management was not my thing, as you can see, cables are visible (this will be an update for the next version).
I put the power bank in the small pocket along with micro USb cable.
In the video I placed it in the zipper pocket but then I moved it in the back pocket for better phone position.
This is the correct way:
Phase Three: Charging
The charging occurs through the transmitter and receiver, when the 2 coils are perfectly aligned. This was a problem so I had to sew the two pockets for better sync.
I found out I can charge at least 2 small tracking devices or a tracking device and the phone.
My phone doesn't have wireless charging so I hacked a micro usb wire on the IDT receiver and Voila!
The receiver is pretty power full and outputs 5.3v no matter the battery voltage (mine was 4.86v)
I found that the receiver also works with Qi smartphones like Samsung Edge.
When the device is charging, the leds on the front of the bag stay on and turn off when charging is done.
There's an inconvenience here as you have to push a button on the power bank for it to start working. You have to press once and it's a push button not on/off switch.
Might be different topic, but if you want the bank to stay on all the time you can solder between 5v and Ground a pulse generating circuit, like the one in the attachment.
The power bank can be charged by microUsb cable or solar panel. As one might guess, the solar panel is not very powerful and a heavier one will make the bag heavy.
Charging gps tracker and smartphone:
So, until I have my hands on a wearable and flexible solar panel, I'll go with this.
TO be continued:
...3d Print case and smaller usb cable.