A minimal, fast, Arduino‑friendly library for calling Google Gemini models from ESP32 boards — optimized for ESP32‑S3 stability, TLS performance, and clean JSON parsing.

AskGemini is designed for:

• Voice assistants
• Embedded AI devices
• Robotics
• IoT dashboards
• Creative LLM experiments on microcontrollers

• Simple one‑call API: String reply = askGemini(prompt, instruction, temperature);
• Works with Gemini 2.0 Flash and other text‑capable models
• Persistent TLS client for fast HTTPS on ESP32‑S3
• Clean JSON extraction (no heavy JSON libraries)
• Optional text sanitizer for TTS engines
• Three polished examples:
  • BasicUsage
  • InstructionMode
  • GrammarCorrector

ESP32 Arduino Core 3.x (Required)
AskGemini uses the modern HTTPS API:

• WiFiClientSecure
• client.setInsecure()
• http.begin(client, url)

These functions do not exist in ESP32 Core 2.x.

• ESP32‑S3
• ESP32‑S2
• ESP32‑C3
• ESP32 classic (running Arduino Core 3.x)

• ESP32 Arduino Core 2.x
• Boards without HTTPS capability

1. Install ESP32 Arduino Core 3.x
   Arduino IDE → Boards Manager → search “esp32” → install 3.x.x
2. Download or clone this repository
3. Place the folder into: Documents/Arduino/libraries/AskGemini
4. Restart Arduino IDE
5. Open: File → Examples → AskGemini

String Gemini_APIKey = "YOUR_API_KEY";
String Gemini_Model = "gemini-2.0-flash";

void errorHandler(int code) {
Serial.printf("AskGemini error: %d\n", code);
}

String reply = askGemini( "Tell me a fun fact about space.", "Respond with one concise sentence.", 0.2 ); Serial.println(reply);

String concise = askGemini( "What is a microcontroller?", "Respond with one short, clear sentence.", 0.1 );

String friendly = askGemini( "What is a microcontroller?", "Respond in a friendly tone suitable for beginners.", 0.4 );

String technical = askGemini( "What is a microcontroller?", "Respond with a technical description suitable for engineers.", 0.0 );

String reply = askGemini( "I did not see nuthen.", "You are a grammar-correcting assistant. Return only the corrected sentence.", 0.0 );

char* cleaned = sanitizeQuip(reply.c_str()); Serial.println(cleaned); free(cleaned); // Important: avoid memory leaks

sanitizeQuip() allocates memory using malloc(), so you must call free() after use.

The ESP32‑S3’s TLS stack is slower than classic ESP32. AskGemini includes several optimizations:

• Persistent WiFiClientSecure (avoids repeated TLS handshakes)
• Keep‑alive enabled
• http.setReuse(true) for connection reuse
• Efficient JSON extraction
• 20‑second read timeout for long responses

• Use shorter instructions
• Use smaller models (gemini-2.0-flash-lite)
• Limit output tokens (e.g., 16–64)
• Add small delays between back‑to‑back calls

• Fix: Updated AskGemini.cpp / AskGemini.h to stable Gemini 2.0 Flash implementation.
• Fix: Improved memory stability and HTTP path handling.
• Internal: Cleaned logging and clarified error behavior.

MIT License.
See LICENSE.txt for details.

Created by William E. Webb