I have a float variable with a value like -99,9 ... Debian,Mint,Ubuntu Arduino Mega 2560 Arduino Nano Arduino Duemilanove MAC OS Montain Lion Raspberry PI Model B. AWOL Guest; Re: Serial.write a float value #1 Jul 02, 2012, 06:45 pm. 5. float is CPU/RAM intensive IMHO In many Arduino projects there is plenty of CPU/RAM left so I don't think this is a real issue. float introduces a rounding problem. That code works. Eighteen Hints to Reduce Code Size 1. Has anyone else solved this problem? Compile with full size optimization. 4. That is, the double implementation is exactly the same as the float… This yields a range of -32,768 to 32,767 (minimum value of -2^15 and a maximum value of (2^15) - 1). The reason that Serial.print(float) is able to print the floating point is because Arduino painfully and tediously implemented the Serial.print() function (the source code can be viewed at ArduinoCore-avr github page, it is almost like a hack) to support the floating point print. Collect non-local data in structures whenever natural. 2. You actually declared ax and ay as floats, so I made that change (to floats) in my source and still got a clean compile in a plain-vanilla Arduino IDE. I could probably modify it if I just knew where 'rounding' is located. I assume it is rounding. The monitor won't display more than 2 decimal places when reading a float var. 3. My motor controller has 4 pins that give a 0-5V output depending on the current the 4 motors draw (5V = 5A). Therefore you need 4 bytes in your array to store each float. On the Arduino Uno (and other ATmega based boards) an int stores a 16-bit (2-byte) value. So I wrote some code to sent the values to the serial monitor and I'm having some problems. Unless you ditch the whole Arduino part and go bare metal AVR with a C compiler, then the code is fine. To prove this point look at how many Arduino projects contain a delay(x00) in the loop; so if things go to slow simply decrease this number to release some CPU cycles ;-). Make an Arduino Sketch Smaller: If you've every hit that 32,256 byte maximum on an Arduino Uno and wondered if you could make your sketch smaller instead of upgrading to a Mega, this is for you! On the Uno and other ATMEGA based boards, this occupies 4 bytes. The Arduino Reference text is licensed under a Creative Commons Attribution-Share Alike 3.0 License. Use the smallest applicable data type. I've searched Arduino.cc, the forum, googled it and can't find anything. If a non-local variable is only referenced within one function, it should be declared static. Double precision floating point number. I must verify my math among other things. I've written a sketch to remote control my Rover 5 with another Arduino with an analog joystick attached. Float has size of 4 bytes. On the Arduino Due and SAMD based boards (like MKR1000 and Zero), an int stores a 32-bit (4-byte) value. Why not just send all four bytes of the float… Use local variables whenever possible. Use unsigned if applicable. ... An example can be found in one of the DHT22 sensor libraries to disable the code that returns float values. Arduino CNC Shield – 100% GRBL Compatable; Programming hundreds of Arduino Minions in one go; Can-Bus Breakout (Picking Can Bus over RS485) DIY Robot Arm by UFactory; Arduino Web Dashboard without the need of web-server; Arduino Float to String (That actually works) SparqEE CELLv1.0: Cellular made easy (Arduino/Pi/+) Float and double are the same on AVRs - they aren't on the Due and some other fancier microcontrollers, but they are for AVRs. An int stores a 32-bit ( 4-byte ) value should be declared.... Due and SAMD based boards ) an int stores a 16-bit ( 2-byte value! 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