Electronics, DIY, programming and more…
I purchased the Huawei Honor Pocket Printer model CV80 from Aliexpress on late 2019 but I didn’t tested until 2021, I was unable to sync it with my Android device using the Huawei Printer app from Google Play, then I tried to scan the QR code on the manual and downloaded the Chinese version of the app, with this version the printer can be discovered and prints correctly.
I seems Huawei as it does with mobile phones and other products has two firmware versions one for Chinese market and other for international buyers. Physically the versions differs only in the color of the front panel and on the name on top, for international units it’s “HONOR” while for Chinse units it’s “HUAWEI”. I got the Chinese version and it’s not supported by the Google Play HUAWEI Printer app.
I couldn’t find how to flash the International firmware on the Chinese printer so I tried another approach to have an app I could understand.
Using the International App with Chinese printer
I followed this tutorial to extract the code from the .apk files and I compared the Chinese version with the International one, the Chinese version seems more updated, but most of the code is the same, then I got two options:
- Change the resource files on the Chinese version to translate the strings
- Discover why International version doesn’t find the Bluetooth device.
Changing the language resources seems time consuming as the Chinese version has more strings and I have to find the corresponding string in the English file or translate the missing ones, so I decided to start by investigating why International version can not find the Bluetooth printer.
I guessed that somewhere the program was filtering the discovered Bluetooth devices either by name or by MAC address, and after some digging I found what I was looking for, luckily the code contains some debug strings that simplifies guessing what it does:
International version, class "com.huawei.cv80.printer_huawei.abroad.ui.connection.BleScanActivity"
Chinese version, class "com.huawei.av80.printer_honor.ui.connection.BleScanActivity"
This code filters by device name, on Chinese version Bluetooth device name has the format “HONOR Printer-9999” and International version uses “HUAWEI Printer-9999”, so I changed the strings on the BleScanActivity.smali and rebuilt and signed the .apk . After accepting the security alerts about using a self signed apk the app was installed successful and now the international version can discover the device and everything works as expected.
International version didn’t found any update, but I was able to update my device with the Chinese version and the help of Google Translate.
I was always intrigued about what is wire wrapping, I already have two wire wrap wire reels bought at eBay some time ago for 8 EUR (12 USD) each but I use it as connection wires for soldering.
Thanks to this great explanation of Bil Herd at hackaday I discovered what it is and how useful can it be for prototyping. I immediately went to buy a wire wrap tool online and I found it cost at least 20 USD, to expensive for the usage I will give to it.
Here I will explain how did a simple wire wrapping tool with results like a professional one. Read more of this post
At my home the ADSL router and my room are in the opposite sides of the house, the Wifi signal that arrives to my room is so low that I can barely use it on my phone or tablet. I have an Ethernet cable that goes from the router to my room so I decided to place a Wifi access point in the middle.
The problem is that there is no power outlet around, the solution is to send the power over the Ethernet cable (PoE) along with the signal. There are commercial products that do it, but is funny doing it yourself and I have an old WRT54GC wifi router that is perfect for that. Read more of this post
Having to travel often for work and I suffered some times the nuisance of having the mobile battery almost drain and not being able to find an outlet to charge it. Emergency chargers are widely available but I prefered to build my own.
This is the bill of material I used:
- LED flashlight for AAA or 18650 batteries (0,5€ eBay)
- Solar Boost DC-DC 3V-5V Adjustable Power Supply Module (3€ eBay)
- 8650 battery (3.7V 2600mA) and charger (less than 5€ eBay) Read more of this post
Are you tired of explaining to your family that they have to remain still until the camera timer triggers? on every family celebration the same history. I always wanted a remote shutter so I don’t have to rely on the camera timer, and if I can construct one for few bucks, much better!
The software CHDK adds to Canon cameras functions that are not present by default, in my case I have a Canon S95 and CHDK lets trigger the shutter when a 5V signal is detected on the USB port. Read more of this post