My Golden Rules:
Note that if deploying image buttons, especially for toolbars, they may have to be defined in pixels (height and width) to minimise distortion. In my experience, square buttons 50pix x 50pix (min 44pix x 44pix) can serve a range of different phone sizes. A Horizontal Scroll Arrangement (aka container) can ensure the User has access to all of the buttons on the toolbar.
Defined and or managed incorrectly, images will take up too much memory and could cause a crash:
Things to look out for:
"Good Housekeeping" pays dividends!
An average of 400,000 Users per month means that you have a lot of competition for the attention of the Power Users (Technical Support Volunteers). Therefore, it is in your best interests to ensure that your help request is very carefully described and where appropriate supported with images and a small Test Project File (.aia) that demonstrates the problem.
If you are communicating with (IOT) hardware such as Arduino, BBC Microbit, Raspberry Pi, Banana Pi -include your Sketch/Script and connectivity (BlueTooth, BlueTooth LE [BLE], Network, WiFi, USB). Include your schematic or circuit diagram too.
If you are having trouble with App Inventor (rather than your work on your App) try this first: MIT: Troubleshooting for App Inventor 2
Description: Tell Us:
How to insert an image of your Blocks into your Forum Post:
How to attach a Project File (.aia) to your Forum Post:
GeneralMIT: Setting Up App Inventor
Learning App Inventor BackMIT Beginner Videos
App Inventor for Teachers BackApp Inventor for Educators
External Storage BackMIT: Using Google Sheets in MIT App Inventor
Activity Starter BackMIT: Using the Activity Starter
Arduino and other Microcontrollers
Hot Tip: Ardunio Sketch (Script): Use println() to separate messages when you transmit.
App Inventor: Set DelimiterByte to 10 in BlueTooth Block.
Check that: Bytes Available > 0 in BlueTooth Block.
Then request -1 bytes to get full message.
Atmel ATtiny85/ATtiny84 (Atmel is part of Microchip Tech) BackOfficial ATtiny85 Website
ESP8266 WiFi Module Back
Hot Tip: The ESP8266 ESP-01 WiFi Module can be used with or without a companion microcontroller. It is an SOC - System On a Chip.ESP8266 Community Forum
LinkIt BackMIT: IoT: Introduction: LinkIt
micro:bit BackMIT: App Inventor Extension for micro:bit
Nordic Thingy 52 BackNordic Semiconductor: Nordic Thingy 52 home page
PIC micrcontrollers BackDesignSpark: Basics of PIC16F877A microcontroller
Rasberry Pi BackDigital Polymath: App Inventor 2 to Control our RPi Robot
8051 8-bit microcontroller (Intel MCS-51) [Embedded Systems] BackNPTEL: PDF: Specifications: Intel 8051 microcontroller
Bluetooth BackJon Gunnar Sponås: Effective Range of Bluetooth Communications
|Text String Character Sets Supported by App Inventor Bluetooth Classic|
|US-ASCII||Seven-bit ASCII (ISO646-US), the basic Latin block of the Unicode character set. 127 characters|
|ISO-8859-1||ISO Latin Alphabet Nº1, (ISO-LATIN-1)|
|UTF-8||Eight-bit UCS Transformation Format|
|UTF-16BE||Sixteen-bit UCS Transformation Format, big-endian byte order|
|UTF-16LE||Sixteen-bit UCS Transformation Format, little-endian byte order|
|UTF-16||Sixteen-bit UCS Transformation Format, byte order identified by an optional byte-order mark|
LEGO MINDSTORMS BackMIT: IoT: Introduction: LEGO® MINDSTORMS® EV3 robot platform
MIT App Inventor Codi Bot BackMIT: IoT: Introduction: Codi Bot
Video Formats BackMIT: App Inventor: Android Video Player Formats Supported
App Inventor Extensions Back
Extensions Library maintained by App Inventor Expert Taifun Baer, including his own excellent ProductsPura Vida: App Extensions
How to install an Extension in App Inventor
Example Extension: MIT Bluetooth Lite Edition (BLE) Extension