Peter Jakab has written a new article on how to adapt character LCD modules for 3 volt operation.
Generic character LCD modules contain an industry standard HD44780 compatible controller, which can operate down at 3 volts. But the modules are usually specified to work only at 5 volts, unless you choose a specific one designed for 3V operation. It is possible and simple to adapt the 5V modules to work on 3 volts.
Getting character LCDs to work at 3 volts - [Link]
HOPERF modules enable to gain a wireless data transfer or remote control of devices simply and without excessive costs.
A company, which specializes over a quarter of century on a given segment usually has experience and production capacities to develop and produce quality components. This is also a case of company HOPERF Micro-electronics and moreover – thanks to high production capacities the prices of their products are very attractive. HOPERF produces RF chips themselves, as well as read-made RF modules usable for virtually any application requiring a wireless control or data transfer, for example: remote keyless entry (RKE), control, security systems, telemetry, voice and data communication, control of processes and many others.
HOPERF modules offer besides a great price also a very high flexibility of usage. In contrast to many “fix-set” modules, RF modules HOPERF usually offer very wide possibilities to dynamically adjust many parameters, like for example: FSK/ OOK/ ASK modulation, possibility to work in a wide frequency range including free ISM bands 315, 433, 868 and 915MHz, while all main RF communication parameters are programmable.
In our stock can be found for example:
- RFM65CW-433S2 and RFM65CW-868S2 – 433/868 MHz FSK receivers. RFM65CW offers a unique possibility to use narrow-band and also wide-band communication modes. RFM65CW is optimized for a low power consumption while maintaining high sensitivity.
- RFM68CW-433S2 and RFM68CW-868S2 – 433/868 MHz FSK transmitters. It can be used without configuration from an MCU. However, in connection with MCU, it´s possible to change many parameters including output power, modulation format and a working channel.
- RFM73-S – 2,4 GHz transceiver, including a high power +20dBm version RFM73P-S2.
- RFM83C-433S1 – sophisticated 433 MHz ASK/OOK receiver including a version for low voltages RFM83CL-433S operating already from 2.1V
- RFM85W-433D – 433 MHz ASK transmitter. Excellent features and simple usage. Specially designed for remote control, car-alarms etc. working on 433.92 MHz.
- RFM12B-868S2P – multichannel 868 MHz FSK transceiver. RFM12B contains integrated functions of a digital data processing like: data filtering, clock recovery, data pattern recognition, integrated FIFO and TX data register. RFM12B enables to provide a clock for microcontroller.
HOPERF – universal RF modules for surprising prices - [Link]
Electro18 posted a tutorial on how to make a portable digital optical tachometer using an Arduino Uno, an instructable here:
A tachometer is a device used to measure the RPM or Revolutions Per Minute of any rotating body. Tachometers can be contact based or non-contact ones. The non-contact or contact-less optical tachometers usually use laser or Infrared beam to monitor the rotation of any body. This is done by calculating time taken for one rotation.
It can measure RPM over 20k
Sensor range extends upto 7~8 cm
Displays Maximum RPM
Measure RPM – DIY portable digital tachometer - [Link]
An inexpensive single board computer which connects to a composite video monitor, keyboard, and SD card by Jack Eisenmann:
I created the DUO Light as a low cost platform for hobbyists to create fun and useful software. The DUO Light is ideal for anyone who wants a low power computer with video output and keyboard input.
The DUO Light is a hybrid of the Arduino UNO and the Raspberry Pi, but costs less than each. At the heart of the DUO Light is the ATMega328, the same microcontroller as in the Arduino UNO. This chip connects to a variety of peripheral devices, including a composite video monitor and SD card (in a similar fashion to the Raspberry Pi), PS/2 keyboard, and general purpose I/O ports. The second chip onboard is a 64 KB serial SRAM, which also connects to the ATMega328.
DUO Light Computer - [Link]
Free PCB Design Tool – CircuitMaker powered by Altium.
You deserve something better. You’re part of the electronics maker and hobbyist community, and you’re coming up with amazingly cool and innovative things every day. We think you deserve better design tools, made specifically for you, to turn those great ideas into reality. That’s why we’re developing CircuitMaker.
CircuitMaker will be a free PCB design tool powered by Altium. With a streamlined interface and powerful engine to boot, you’ll never have to worry about your software holding you back. This will be a free design tool unlike anything you’ve seen before.
Free PCB Design Tool – CircuitMaker powered by Altium - [Link]
A magnetic stirrer uses a rotating magnetic field to mix fluid samples, such as buffers and media for growing bacteria. Since only a small magnet bar has to be put inside the sample/fluid, the risk of contamination is minimized. For protein purification, overnight sample dialysis steps often utilize magnetic stirrers.
Below are beta release DIY instructions for a magnetic stirrer this summer, courtesy of Malcolm Watts and Massey University in New Zealand. The stirrer runs of off a battery and has multiple speed settings.
You can also download the pdf: magnetic_stirrer_betarelease_V01
Magnetic Stirrer - [Link]
Trandi blogged about his RC servo and stepper motor project. He writes:
For those interested in reproducing this example:
The board is called “EP2C5 Mini Board” and has a EP2C5T144C8 Cyclone II FPGA on it
I used a standard, 9grams micro RC Servo
I used a 28BYJ-48 stepper motor and it’s driver (you can purchase these as a bundle for very cheap on dealextreme or banggood)
I used the free edition of Quartus II from Altera, version 13.0 SP 1 (be careful, later versions do not support Cyclone II FPGAs anymore)
I created a simple project, pasted all this code as a single module (it would of course be cleaner to separate the RC Servo and stepper control code into independent modules)
made the “Top level entity” in the General configuration page equal to “counter” (the name of my module)
used the Pin Planner to assign the inputs/outputs as follows:
FPGA : RC Servo and Stepper motor control in Verilog - [Link]
Remote control your electrical devices through your local network or internet. The circuit contains one output (Relay) and one input (isolated input). The whole project was built by using arduino nano platform and an ENC28J60 ethernet module. It can be used the W5100 ethernet module instead of ENC28J60, by replacing the UIPEthernet library to Ethernet library.
Moreover, the control is made from the Android application I wrote and it’s available on Google Play (https://play.google.com/store/apps/details?id=com.serasidis.NetworkRelay).
The schematic diagram, arduino sketch, photos and demonstration video is on my web site:
Arduino Network relay - [Link]
Davide Gironi writes:
DS18B20 is a programmable resolution 1-wire digital thermometer.
It has an operating temperature range of -55°C to +125°C and is accurate to ±0.5°C over the range of -10°C to +85°C.
This library is an AVR implementation to retrive temperature from DS18B20.
Built using the reference document: “Using DS18B20 digital temperature sensor on AVR microcontrollers” by Gerard Marull Paretas, 2007.
A DS18B20 1-wire digital thermometer AVR ATmega library - [Link]