C/C++/Arduino Datatypes

Type Byte Bit Typical Range
boolean 1 8 true/false
char 1 8 -128 to 127
signed char 1 8 -128 to 127
unsigned char 1 8 0 to 255
byte 1 8 0 to 255
uint8_t 1 8 0 to 255
int 2 16 -32,768 to 32,767
short 2 16 -32,768 to 32,767
signed int 2 16 -32,768 to 32,767
unsigned int 2 16 0 to 65,535
word 2 16 0 to 65,535
uint16_t 2 16 0 to 65,535
long 4 32 -2,147,483,648 to 2,147,483,647
float 4 32 -3.4028235E+38 to 3.4028235E+38
unsigned long 4 32 0 to 4,294,967,295
uint32_t 4 32 0 to 4,294,967,295
uint64_t 8 64 0 to 18,446,744,073,709,551,615

Calculate series resistor for 0805 SMD LEDs with different colors

When I plan SMD LEDs for one of my PCB designs, I always ask myself which series resistors I need. At AliExpress dealer CHANZON Official Store I found the following nice overview. The series resistor can then be calculated with hte LED Resistor Calculator.

Can’t import SVG’s to Fritzing Part Editor created with Adobe Illustrator

When I tried Fritzing for the first time today, I unfortunately had to notice that two parts are missing. A NodeMCU has already created and released squix78, thanks for that. But unfortunately I could not find a RS232-TTL converter (MAX3232). No problem, then I just create an own part. With this manual this is relatively easy. Unfortunately the part editor did not accept the SVG’s I created with Adobe Illustrator. After a long time of trying I found out that the following export settings are necessary. Important is the number of decimal places:

The final part:

You could download my MAX3232 RS232-to-TTL-Converter Breakout Board here. To use it, drag and drop it into you sketch.


Download Fritzing for free (with out donation)

I just wanted to test Fritzing today, but it is not so easy to download the program. On the website it is only possible to download it after a PayPal donation. Unfortunately the binaries are not available on github. Please don’t get me wrong, I don’t have anything against donating for free software, but I don’t like to force this on everyone. At the end, I found something after all:

TL;DR: Sign up for an acccount (or use bugmenot.com) and then you can select “I already paid” and download the binary for you platform. If you like Fritzing, please donate.

FDTI USB-to-Serial adapter showing only gibberish

I order two new – cheap – FTDI FT232RL USB-to-Serial Adapters on AliExpress.


After connecting, the first disappointment came directly. The Windows Device Manager displayed no COM port. Only a USB Serial Converter. The update of the driver brought no improvement. By coincidence I discovered the “Load VCP option. After I activated this, the USB Serial Interface was displayed correctly.

2016-09-04 16_49_23-Eigenschaften von USB Serial Converter

Quickly the next disappointment came, both showing only gibberish.

I thought at first that the baud rate is incorrect, but with an older adapter it working correctly. On the FTDI website i found a tool called “FT_Prog”. With these programming utility you can read and write the EEPROM for use with FTDI devices. After a few clicks I could see the difference:

2016-09-04 16_24_14-FTDI - FT Prog - Device_ 0 [Loc ID_0x212]

2016-09-04 16_28_39-FTDI - FT Prog - Device_ 0 [Loc ID_0x212]

Since I was not sure if there are other differences, I used the template function of the tool to copy the settings.

2016-09-04 16_37_31-FTDI - FT Prog - Device_ 0 [Loc ID_0x212]

2016-09-04 16_38_10-FTDI - FT Prog - Device_ 0 [Loc ID_0x212]

2016-09-04 16_38_39-Program Devices