Pressure, temperature and humidity sensor based on MS5637 HDC1080

Mare writes: This is another small module to measure air pressure, temperature and humidity. Two sensors are on-board: MS5637 and HDC1080. Microcontroller is small cortex M0 in TSSOP-20 housing from STM: STM32F070CxP. The SN65HVD72DGKR provides RS485 interface functionality with half duplex mode. Voltage regulator, reverse polarity protection and some LED indicators are provided on-board. Complete […]

USB to RS485

Marko Pavlin has published a new build: Testing of sensors with RS485 using PC without proper interface is not possible. Since RS232 interfaces are very rare, the interface should be hooked to USB. The interface between USB and RS485 can be soldered with one of the many FTDI interfaces with added RS485 driver, or bought […]

Software Serial Modbus Master over RS485 transceiver

Colin writes: We like cheap, well-made temperature controllers. Sure, we can make our own, but for a modest sum we can get a nice NEMA-rated package capable of reasonably complex logic with a communications interface. The Love 4C and 16C controllers can both be had for <$100 fit this description and make dependable control and higher-level […]

Open hardware USB to RS485 adapter

Ethan Zonca of Protofusion writes: While developing the Luma RS485-networked LED driver we discovered a need for a small and inexpensive USB to RS485 adapter. We designed an adapter with a FTDI basic UART chip (FT230XS) and an inexpensive TI differential receiver (SN75176). Our small selection of parts brings the cost down to just over […]

App note: Using the LTM2881 as an Isolated 5V power supply

Here is an app note from Linear Technology on how to use their LTMM2881 isolated RS485 transceiver as a isolated 5v power supply. The LTM®2881 is an isolated RS485 transceiver that guards against large ground-to-ground differentials. An onboard DC/DC converter provides isolated 5V power to the output.

Controllable aquarium moonlight strip

Theatrus build a controllable aquarium moonlight strip. Royal-blue Osram high power surface mount LEDs provide the lighting, and an ATmega88 the control. RS485 port is used for control. All of the design files should be available shortly. Its quite potent (visible with the main 6x80W T5s running). Its easy to mount (a handful of command strips […]

RS-485 and Arduino

As seen in the above illustration from National Instruments, RS-485 ports are identical in appearance to RS-232 but with different pin assignments. You will not find them on contemporary home computer hardware, and they are only rarely seen on legacy machines. They are, however, found on various types of commercial computer and telecom equipment and […]