Tag Archives: LCD

Battery Powered Frequency Meter (0 to 20kHz)

The circuit is a simple digital frequency meter that is made of a frequency-to-voltage converter and an analog-to-digital display converter that can be operatedfrom a single 9-volt battery. The TC7126 ADC generates the voltage required by the TC9400 FVC with internal regulators. The TC7126 is designed to directly drive a 3-1/2 digit, non-multiplexed LCD display so no digital conversion is required.

The input circuit is made up of a current limiting resistor (33kΩ), a DC blocking capacitor (0.01µF), a clamping diode (1N914), and a biasing resistor (1MΩ). The diode acts as a soft clamp to prevent negative going transitions from latching the comparator input and the 33kΩ resistor limits the current during the positive transitions. The gain (VOUT vs. FREQIN) of the TC9400 is determined by the charge-balance capacitor and the integrator feedback resistor (620kΩ) that has been selected for an output of approximately +2V (referenced to ANALOG COMMON) with frequency input of 20kHz. The bias resistor (12kΩ) determined the input threshold of the comparator and has been selected for an input sensitivity range of 250mV to 10V peak-to-peak of a sine or square wave on the input of the FVC.

The TC7126 will have a maximum positive input of about 2V since the input is referenced to ANALOG COMMON that is only 3V below V+. The internal voltage swing of the integrator does not have the same limitation because a positive input results in a negative swing of the integration. A fully charged battery will give a range of about 6V. The integration components (1MΩ and 0.047µF) at pins VBUFF and VIN are selected, in conjunction with the oscillator frequency to have an integrator ramp amplitude of about –3V with a 2V input from the TC9400. The oscillator is set up to run at 48kHz (150kΩ and 50pF) for maximum rejection of stray power-line pickup. This will result in the TC7126 running at three conversions per second.

Battery Powered Frequency Meter (0 to 20kHz) – [Link]

Arduino Distance Meter


Paoson Woodwork @ instructables.com has build an Arduino Based Distance meter using SR-04 Ultrasonic sensors and an LCD display:

This a project I’ve been working for some time now. It is a device that shows in a little LCD display the distance to the nearest object it can find, usually the floor, the ceilling and two walls or columns. So it can be so helpful to hang a picture, a shell, a light point, calculate the area of the entire wall, etc.
The sr04 has a 3mm resolution, so I am only using it in entire centimeters. You can also change it to inches pressing a button but then the resolution is even worse. I am trying to figure out how to get a better resolution, I know it is possible. Needless to say any help will be appreciated.

Arduino Distance Meter – [Link]


Home Thermostat With Arduino and LCD


ArisK3 @ instructables.com decided to replace his home thermostat with a DIY one so he build an Arduino based thermostat with big character LCD.

Replacing a standard thermostat (SIEMENS-RAA30 16GR) with a self made, arduino-based, big LCD screen is a fun project.

Home Thermostat With Arduino and LCD – [Link]


Portable Ultrasonic Range Meter


ManosM @ instructables.com has build a portable ultrasonic range meter based on ATMega328 mcu and LCD display.

This device is a small, portable ultrasonic range meter using an ATMega328 microcontroller, an ultrasonic module and a 4×20 LCD for ranging distances in meters and inches.

Portable Ultrasonic Range Meter – [Link]

Smart Watch


Matthew Filipek from Cornell Univercity has build a nice smart watch with 1.7 inch touch screen, SD card, Bluetooth module and various apps.

One of the main inspirations for this project was Jared Sanson’s implementation of a DIY smartwatch (REF 0). With several design iterations, he was able to produce a watch in a very small package that can communicate with a PC via USB HID, features an OLED display, and has support for an accelerometer. As my project was to be completed in the span of a mere month, several of the components I got were purchased for their ease of use rather than their compactness.

Smart Watch – [Link]

chipKIT Tutorial: Using Nokia 5110 LCD


Raj @ embedded-lab.com has posted another great tutorial on how to interface a Nokia 5110 LCD to chipKIT board.

Today, we will see how to connect a NOKIA 5110 graphical LCD (used in Nokia 5110 cell phones), which is a 84×48 pixel monochrome display of about 1.5″ diagonal in size. The display can be used for graphics, text, and bitmaps.

chipKIT Tutorial: Using Nokia 5110 LCD – [Link]

Better 3D graphics on the Arduino – ILI9341 LCD


M Rule @ crawlingrobotfortress.blogspot.com discuss about ways to optimize 3D rendering on ILI9341 LCD and Arduino:

Both optimizing ILI9341 LCD drivers and rendering basic wireframe meshes have been done before. XarkLabs provides an optimized fork of Adafruit’s library. Youtube user electrodacus has also implementd an optimize driver for the ILI9341 communicating over SPI.

Better 3D graphics on the Arduino – ILI9341 LCD – [Link]

DIY I2C LCD Display


sspence @ instructables.com shows how to interface a character LCD using I2C and only two IO pins.

The typical parallel LCD used with an Arduino (16×2 or 20×4) has 16 pins. Only 6 I/O pins are required on the Arduino, but what if you could get that down to two I/O pins, and still have those pins available for other devices?

The I2C interface is on pins A4 and A5 of the Arduino. These are addressable, and are therefore shareable with other I2C devices that have different addresses.

DIY I2C LCD Display – [Link]

Arduino Tutorial: Using the Soil Moisture Sensor along with a Nokia 5110 LCD display

Using the soil moisture sensor with an Arduino can’t be easier. Adding a Nokia 5110 LCD display makes things more professional since we can visually check the moisture levels of the soil.

The sensor can measure the levels of moisture in the soil. So it can be extremely useful if you want to monitor the soil moisture of your plants or automate the watering procedure. Let’s see the project we are going to build today. I have one cup in front of me with dry soil. If I place the sensor in the cup we can read a low soil moisture value at the Nokia 5110 display. If I pour some water in the cup you can clearly see that the moisture levels rise. The project is working fine and we can visually check the moisture levels of the soil. Of course this is just a demonstration of the sensor, I am going to build more useful projects in the future with this sensor. Let’s now see how to build this simple project.

Arduino Tutorial: Using the Soil Moisture Sensor along with a Nokia 5110 LCD display – [Link]

LCD clock with 4″ display


mcs.uwsuper.edu has build a big LCD clock based on MSP430 mcu and DS3231 RTC clock chip. They write:

The clock is built on a 4″ (101 mm) LCD displays OD-103 manufactured by Orient Display. The LCD provides high contrast of digits and easy reading from a large distance. The unit runs on batteries and can also be powered from mains. Here is how it looks under direct sun.

The time keeping is provided by DS3231 RTC chip with an integrated high accuracy (± 5ppm) MEMS crystal. This makes PCB design very simple, as one does not need to take care on special traces design around the crystal.

LCD clock with 4″ display – [Link]