box-keychain

An ink screen that hangs on your key

A picture is changed every 30 minutes, and it can be on standby for more than 20 days. Pictures are uploaded in the background by itself. Press the button to update one picture. If the picture is not refreshed, press it 5 times continuously to enter the picture transmission mode.

Connect the PC to WIFI and connect to the Album, and open the Loader interface of http://192.168.4.1 WeiXue.

There are two versions of the ESP8266 box, one for wireless charging and one for typec (sink plate) charging.

The ESP32 version is at : https://oshwhub.com/guozhaowen/box-keychain-esp32

storage

The pictures are saved in flashj, and the app space is compressed as much as possible, with a ratio of 1M (APP) + 3M (File). The sound quality of each picture is 5K, and the two colors are 10K. Although the 3M space can still store 200 pictures.

Or you can change the Flash yourself, GD25Q64CWIG 64M, 6-7M space is enough. The following welding diagram I bought "GD25Q64CWIG WSON-8 64M-bit 3.3V" from "Chuyi Technology"

In order to reduce the thickness, try not to use SOP8 first, but WSON8.

The last board to be built is ESP32 PICO-D4 + SDNAND (it is a TF card, no slot required, space starting from 1G (128M))

From ESP8266 12F (4-16M) to ESP32 PICO-D4 (4M), to ESPP32 PICO-D4 V3-02 (8M)

In fact, the 4MFlash of ESP8266 12F is basically enough for 200-300 pictures. If it still doesn't work, just change to flash 8-16M, which is enough.

In order to control the thickness, the area where esp826612f is used is cut off, which makes welding a little troublesome.

If you are a novice, I suggest you get a steel mesh. FPC is not easy to weld without a mesh. The price of 10x10cm is 15 yuan + 10 yuan express fee. The boss is very nice. Sometimes I put two small boards together and the boss doesn’t say anything. What, just don’t fight too hard.
Taobao connection: https://xiaorong88.taobao.com/

Find the battery yourself, 303035 is thinner, or 403035 is one millimeter thicker.

In order to save space for ch340 on the board, downloading requires a downloader: https://oshwhub.com/guozhaowen/Ch340C-6Pxia-zai-qi-ESP23-8266

It is recommended to use 0.8 for the board (pursuing the thickness of the box).

Currently, only ESP8266-12F firmware (4MFlash and 8MFlash) is provided, which supports good display red and black and white screens. The yellow color is exclusive to my daughter and is not available for the time being.

The firmware limits the uploading of only 20 pictures for testing purposes.

Wireless charging instructions:

The main controller is NU1680. Only one store sells it, Xubao, but it’s not expensive at only 3 yuan.

If you want to use wireless charging, it is best to print with PETG material. If the wireless charging temperature is not low, PLA will become soft.

When assembling, it is best to use gold fingers to wrap the 0.02 LV board and stick it on the NU1680 for heat dissipation. If there is no LV board, you can also find a can.

The capacitor used for wireless charging is 0402, which requires NOP ceramic chip capacitors, which are more expensive.

The small steel mesh used to join the panels is very practical.

The steel mesh above scrapes the tin

The effect after the hot stage shows that there are almost no excess solder beads, but it is a pity that the ESP32 is placed in the wrong direction.

Before putting on the board, no matter whether your chip is gold-plated or not, you must rub it with a fine sand strip a few times. Don't ask why, I just tell you that the welding success rate will increase by 90% in one time.

Take a look at the effect

Aluminum plate, a few wallets for mail.