General • MiniPico V4

Since I made the small gameboy type device, I have since continued to modify the design.

The gameboy device is nice, but I wanted more keys. The idea was to create a small battery powered device with pi pico w that can do it all.

Features:
-PI PICO W
-16 key keypad
-915mhz LORA transceiver
-DS3231 RTC
-3.3v LDO to supply RTC
-IR transceiver
-buzzer and led for alerts
-two 0.96 OLED displays
-1200 mAh LiPo
-TP4056 charging IC
-60 mA solar panel for keeping battery topped off or slow charge over days
-soft power button
-hard power switch to disconnect Battery from pico and pullups from LDO

I feel like I am missing something, but I will post full schematics when I am on PC.

Received the PCBs and components this week and have begun to assemble. I have 5 pcb's, and parts enough for 3 devices.

I made a mistake when i installed the RTC. it has a tiny "+" sign where the dot should be, but it was barely visible.on the bottom there was another dot. I didnt see the "+" and went off the bottom dot, long story short i installed it backwards. I will have to examine the schematic more to see what vcc was connecting to. I think it was ground pin of RTC. Anyway, i desoldered that one and saved it for later testing and put a new one in. New one is working great, but i cannot get MCP23017 to respond. They share I2C net. Maybe it fried that too. Thankfully i have 3 of each of those IC.

I forgot to add pullups for lora transceiver. It may or may not work without them. We'll see. On this version if so, will add jumper resistors.

Also IR led will not have much power driven directly from GPIO... a transitor will be in next design.

On the soft power switch I and one of transitors i had some cold solder joints, marked them with tape, will fix tomorrow.

Lora module and keys will be installed last if everything else checks out.

I am soldering this all with an soldering iron. The 0603 components and the SSOP IO IC are tricky to solder and it just takes some time, flux, patience, and a desoldering wick.

Pics of progress:MiniPico v3 was smaller, with one oled, and 12 keys. If anyone is interested i can post a pic of that one too. I liked the smaller size, but to add more features it got bigger. I developed a menufor that one i plan on using on this one, as well as tools such as display serial data on display, i2c scanner, etc.

Statistics: Posted by picoprojectmaker — Sat Feb 03, 2024 8:30 am — Replies 1 — Views 78

---