Description
Features
- Lower Key Height / More Ergonomic Keyboard
- Raised outer ridge to prevent accidental keypresses
- Recessed power switch
- Alert Buzzer
- Textured Grips / Edges
- Sunshade for Screen – Also provides protection and prevents accidental keypresses while face down
- Recessed antenna mount to reduce overall size and protect antenna
- Brass inserts for screws allowing easier reassembly
- Attachment loop to hook device to backpack, tree, bike, etc while out exploring
- To-Do: Optional replacement backplate including a kickstand when stationary.
Parts Selection for Building:
The links below are sponsored promotions through the Amazon Affiliate program. Purchasing parts through these links ensures part compatibility and greatly helps me to fund further products!
Depending on what you want to build, you may have to pick and choose parts! You may choose to use different parts from different vendors, which will likely be cheaper if you do not need large quantities of screws and such!
Build Notes
- The case is designed to fit a Heltec V3 WITHOUT pins! You will need to solder all connections!
- The case is designed to fit a CardKB without pin header! You will need to remove the plug and solder directly to the CardKB.
Electronics
- Heltec V3 LoRa – https://amzn.to/4cIXtGz
- CardKB – https://shop.m5stack.com/products/cardkb-mini-keyboard-programmable-unit-v1-1-mega8a
- GT-U7 GPS Module with Ceramic Antenna – https://amzn.to/4rAQO54
- 2n7000 MOSFET (optional, battery save for GPS) – https://amzn.to/3NiFa0E
- 3000mah 105050 Battery (10x50x50mm) – https://amzn.to/41Hxt7E
- Mini Buzzer (9×5.5mm) – https://amzn.to/4sR5T3X
- SPDT Switch (11x6x12mm) – https://amzn.to/4sQVG7f
- Whip Antenna (optional) – https://amzn.to/4tozQrT
Hardware
- M3 Button Head Screws (8mm) – https://amzn.to/3P8Seq0
- Heat Set Threaded Brass Inserts (M3xD5-L4) – https://amzn.to/4lCJ55a
Wiring and Pinout
GPS
-
GPS VCC → Heltec 3.3v -
GPS TX → Heltec GPIO 48
-
GPS RX → Heltec GPIO 47
-
GPS GND → MOSFET DRAIN
-
MOSFET SOURCE → Heltec GND
-
MOSFET GATE → Heltec GPIO 26
Buzzer
-
Buzzer Positive → Heltec GPIO 7 -
Buzzer Negative → Heltec GND
CardKB
-
CardKB GND Pin 1 → Heltec GND -
CardKB 3.3v Pin 2 → Heltec 3.3V
-
CardKB SDA Pin 3 → Heltec GPIO 41
-
CardKB SCL Pin 4 → Heltec GPIO 42
Battery
-
Battery Positive → Heltec Positive Battery Terminal (JST-GH 1.25mm) -
Battery Negative → Switch → Heltec Negative Battery Terminal (JST-GH 1.25mm)
GPIO pins are tested to work with my device configuration. You may use alternate pins if needed.
Software Configuration – Configure via App
Device Config
-
Buzzer GPIO → Pin 7
Position Config
-
Device GPS → Enabled -
GPS Receive GPIO → Pin 48 -
GPS Transmit GPIO → Pin 47 -
GPS Enable GPIO → Pin 26
Canned Messages Config
-
Options → Enabled -
Presets → M5 Stack CardKB
External Notification Config
-
Enabled → True -
Alert Bell → True -
Alert Message → True -
PWM Buzzer → True -
Active → True -
Output GPIO → Pin 7