Universal RFToy for quick and easy interfacing Radio frequency modules

Radio modules are great for interfacing remote objects without need of wires. They are cheap and fairly easy to use. With Arduino things are even better as there are software libraries already ready for use. Rayshobby went even further. They designed a small board that incorporates Atmega328p with Arduino bootloader. 128X64 OLED display, coin cell battery, few navigation buttons and most importantly headers for plugging in various RF modules. In fact normally you would need two types of modules – nRF24L01 that comes with both receiver and transmitter, and two different four pin modules that work in 433/315Mhz frequencies. Each board works as standalone device that can be paired with other and so creating virtual wires. Few demos demonstrate how they can be used as RF recorder storing 7different signals or controlling 7 different devices. Another use is so popular wireless temperature sensor where remote sensor temperature can be displayed on receiver’s OLED display. Modules are also equipped with 3.5mm audio jack that gives ability to record and analyze RF raw RF signals wit software like Audacity. Continue reading

Fun FPV RC tank

If you have an Android phone you can download IP Webcam application and have remote IP camera where you can see video stream in web browser screen. But this stuff may become boring as you camera isn’t moving. Nikus decided to build a better solution that would allow follow things with FPV (First Person View). He took Arduino Leonardo and equipped it with robotic threaded platform. He used H-bridge TB6612FNG circuit to control motion motors. Also he added two servos for camera pan and tilt control. He built RF remote link by using two NRF24L01 modules. On his remote control he assembled two joysticks that are interfaced to another Arduino. After assemble was complete he had great robot that can move around the house and record videos. Since video is streamed to PC, it becomes easy to control. There can be lots of funny video made while crawling around. Continue reading

BridgeDuino can carry most of wireless adapters

When project goes wireless prototyping with breadboard can be really messy. This is OK with single module, but what if you need several options? This is why TechBitar designed BridgeDuino board that can work as Arduino shield or HUB that can carry several popular wireless adapters including IR transmitter LED, IR receiver, RF433MHz reseiver and transmitter, Bluetooth HC-06 and HC-05, and Nrf24L01+. Board can sit on top of Arduino Uno as shield or be as base for Arduino Pro Mini along with FTDI programmed adapter. All those adapters already have Arduino libraries available, so there is no problem to interfacing them you just need to be sure when selecting proper control and data pins. BridgeDuino also has several additional features that make life easier. For instance LM1117 3.3V supply for powering Nrf24L01+ module, battery power option with Schotky diode protection, jumpers for programming and configuring other adapters, several I2C and ADC headers. Continue reading

AVR RF based bootloader

Sometimes when you deploy your device for permanent use it is not always convenient to connect to it in order to perform software upgrades. Necromant wanted something convenient and cheap that would allow him to connect to AVR without wires. Since he already had several nRF24L01 RF dongles he decided to build so called over-the-air bootloader. He ported Arduino based nRF24L01 library to AVR by removing Arduino dependencies along with few fixes. One RF dongle is attached to target MCU using either hardware SPI or software SPI. Bootloader fits in to 4KB. As programmer, there is a uISP dongle used where nRF24L01 sits on top. Currently programming speed isn’t great which is probably mostly limited by V-USB. Since RF dongles can handle up to 2MBPS speeds there are plenty space for improvements. But rather sticking to AVR, Necromant plans to build another dongle which will be STM32 based USB chip. Continue reading

Reducing interfacing pin count for nrf24l01

Sometimes we get caught in situations when we need direct solutions without figuring things out in more efficient manner. For instance microcontrollers and pin count. When we need more pins, we start looking for bigger MCU even if processing power is enough even if one additional pin would change the situation. So sometimes this is not effective to waste money and even design to get one or two additional I/Os. Some people may use I/O port expanders or shift registers to get more pins. But as Ralph shows we don’t always need head for obvious. There are tons of discrete electronics components around that may save the day. This time he suggests interfacing well known nrf24l01 RF module to small MCU like Attiny85 by using 3 pins instead of 5. So here it is a discrete schematic which does the magic. First of all Rf module is 5V tolerant except VCC must be powered between 1.6V to 3.6V. So a simple LED reduces VCC to save range. CE is another pin that can be tied to high. CSN signal was… Continue reading