Introduction: Smart Messenger Bag With Wireless Charging
We will be making a smart leather messenger bag that features wireless charging and a Bluetooth strap that pairs with your phone and vibrates when receiving texts or phone calls
coin cell vibrator
hc-05 Bluetooth module
3.7v lipo baattery
tpc4056 charging module
messenger bag or leather to make one
Step 1: Cut Leather for Strap Pad
cut two pieces of 3.25" x 9" leather for the strap. I am using 7oz natural veg tanned leather.
Step 2: Solder Components
cut 4 pieces of ribbon cable in half. attach the cable connectors to the hc-05 module and solder the other ends to the Arduino. The pin configuration can vary, this is just how I did and it matches the provided Arduino code
vcc to 3.3v
ground to ground
txd to d10
rxd to d12
solder ground (blue wire) of vibrator to ground of arduino and positive(red) to A5
solder positive and ground battery wires to positive and ground battery out pins on tp4056
solder ground output of tp4056 to ground in arduino. then solder positive output of tp4056 to switch and switch to 5v on arduino
You will also likely need to replace the rprog resistor on the tp4056 to make sure the appropriate current is applied when charging the lipo battery. google tp4056 charging current to learn more
Step 3: Glue Components to Strap
glue the soldered components in between the holes in the strap. I used hot glue and small dabs of super glue. be careful with the super glue as it hardens leather easily.
Step 4: Upload Code to Arduino
The code can be found here: https://github.com/morsscode/smart_bag/blob/master/smart_bag.ino
Step 5: Test Circuit With Bluetooth Terminal (optional)
you can download Bluetooth terminals from the app store. we will test using the terminal to make sure the arduino is working without having to worry about the app we will be making causing any potential problems. send 0 to test the text vibration and 1 to test the phone call.
Step 6: Download App to Phone
the app was made using MIT app inventor. it can be found here: https://github.com/morsscode/smart_bag/blob/master...
you can drag and drop the file into your phone. You then will likely need to change app instillation permissions to install it from wherever you have placed it in your phone. Once the app is installed you can test it by opening the app, switching on the strap and emailing yourself a text and or use an additional phone to call the paired phone.
Step 7: Leather Electronics Cover
glue a thin piece of leather over the electronics. glue three of the edges to the strap and leave the edge covering the charger and switch open. Adding the cover will allow the strap to slide much easier through the strap pad without catching the electronics.
Step 8: Glue and Sew Strap Pad Together
glue the two strap pad pieces together and sew the edges. I have used a saddle stitch.
Step 9: Wireless Charging Bag
Next we will cover how to mount a wireless charging unit to the messenger bag
Step 10: Strip Wireless Charging Unit
purchase a wireless charger and remove it from its plastic casing. Alternatively you could opt to try and connect the charger directly to the bag as is. I used an Anker circular wireless charger.
Step 11: 3d Print Charger Case.
3d print the charger case pieces and glue them together with the wireless charging unit.
The 3d print files can be found here: https://github.com/morsscode/smart_bag
The case fits my galaxy s7 and should fit similar sized phones.
I chose to use clear filament for the charger cover so the blue led can be seen when charging
Step 12: Run Cables
cut slits in the back of the two front pockets of your messenger bag and feed the charger cable between them.
Step 13: Sew Charger to Bag
use the holes in the 3d printed case to sew it to the bag inside the pocket. Plug the charger into a power bank and test it out.
Step 14: Assemble the Rest of Bag
Either sew the rest of your bag together or sew any fixes in the messenger bag you purchased and you are all done!
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