Some of my posts were dedicated to Remote controlled relay board or . But in many situations, this board was too big. I made another board for this cases and, of course, I made new application for DCTR module. Now, straight, for DPA, but if you want, you can make a simple P2P application from published source code.
Today, we are going to tell something about wireless traffic lights for BMX races. Here it is necessary to control a pair of riders, so they does not enter both on the track simultaneously to avoid collision. This traffic lights alternately allows to enter one of drivers to track, then 10 seconds is red color on both devices (entrances) and then driver from the second entrance is allowed to enter the track.
If You are interested in LED driving through RF, this article would be interesting for you. I tested own PCA9634 breakout board for this chip and wrote simple low level driver for IQRF TR-52D module. Next week, I am going to publish PC application for comfortable operation with that.
In this article you can read about working with RGB LED diode. You can display 8 colors using one LED diode. LED is connected by 3 pins to MCU for control color and by 1 pin is connected to MCU via transistor to regulate brightness (see scheme). Regulation of brightness is performed by PWM.
I like TR-52D modules, but I was disappointed of their DAC capabilities inherited from used MCU. Fortunately we have several ways, how to fix this issue. One of them is AS1500 digital potentiometer usage. It is very simple (from programming view) device and not so expensive. Following example is only draft. For fully functional circuit, some additional hardware is required.
A library described below uses bit banging technique to connect serial SPI RAM to any free MCU pins thus keeping SPI slave interface free for other purposes. In our example we use 256K memory 23A256/23K256 from MICROCHIP. A different type with the same protocol or different capacity can be used too.
This demo application shows how to do simple wireless digital compass. We used a 3rd party compass module with HMC5883L sensor. The Compass Module is designed for low-field magnetic sensing with a I2C interface, to provide heading information for your microcontroller wireless project.