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Spectrum analyzer code for Arduino platform

Posted on October 26, 2016 by R-B One comment

Spectrum analyzers measure the frequency components contained in an input signal and displays their amplitude as a function of frequency. The amplitude is shown on the y-axis and the frequency in the x-axis. They are useful in computing transmitter and receiver RF power at antenna tower station, measuring the bandwidth of a transmission channel, detecting interference in channels, computing transmission losses, etc. For basic DIY applications, there is a spectrum analyzer code from agp.cooper for Arduino platform. It is ported to ATTiny85 but can be easily used with other Arduino compatible processors. It uses Goertzel’s algorithm with a Hamming window for DFT computations and Nokia PCD8544 LCD for displaying the signal strengths as a function of frequency.

Spectrum analyzer

DIY bike speedometer

Posted on April 23, 2015 by R-B One comment

Check out this detailed build of Arduino-powered speedometer to monitor your bike speed on road. The project uses a reed switch to sense the rotation of one of the bike’s wheels. The Arduino reads in the reed switch closings and calculates the bike speed in mph. The calculated speed is displayed on a LCD screen. The speedometer is calibrated by defining the radious of the wheel in the firmware.

Arduino bike speedometer

Secure both the magnet and reed switch to your bike wheel with electrical tape (either wheel is fine). As shown in the images above, the magnet connects to one of the tire spokes and the reed switch connects to the frame of the bike. This way, each time the bike wheel turns the magnet moves past the switch. Connect the leads form the reed switch to the long wires from your protoboard (orientation does not matter here- it’s just a switch)

DIY Spectrophotometer using Arduino

Posted on April 21, 2015 by R-B Leave a comment

Spectrophotometery is a quantitative measurement of the transmission properties of a chemical substance as a function of wavelength, and the device used for this purpose is known as Spectrophotometer. It operates by passing a beam of light through a sample and measuring the intensity of light reaching a detector through the sample. This Instructable describes an Arduino controlled DIY Spectrophotometer made by two undergraduate biochemistry students-Peter Elphick and Ed Tye, for their final-year lab project.

Arduino powered Spectrophotometer

We wanted to make a spectrophotometer that would measure the concentration of a dye called OPD; a common dye in biological assay kits. In addition to reading the absorbance of the samples, we wanted to make a spectrophotometer that worked with 96-wellmicroplates. These are disposable, multi-sample plastic dishes and are the backbone of assays in academic and pharma bioscience labs. They hold 96 samples of up to 0.35mL, arranged in a grid. Pharma labs like them because they lend themselves to robotic handling and high-throughput assays.

We reckon that the final machine cost about £500 ($750), although a lot of that could be saved if you machine your own frame.

GPS based car locator

Posted on April 19, 2015 by R-B Leave a comment

Keep forgetting where you have parked your car in the parking lot? This Arduino-based car locator uses GPS to remember where you park with just the push of a button and later tells you how far you are from it and in what direction.

The GPS continuously reads the latitude and longitude of the CarTracker. When the button is pressed, the coordinates are saved to the EEPROM. E.g., this would be the location of your car.

Now, let’s say you walk out of a store and are looking for your car. Power up the CarTracker. Do not push button. The GPS will read the coordinates of the store and will calculate distance and direction from there to the stored location (of the car). The compass will orient the display so the display will point to the car and will display the distance.

GPS car locator

DAN64: A DIY 8-bit microcomputer using Arduino

Posted on April 7, 2015 by R-B Leave a comment

Juan J. Martínez’s DAN64 is a single board 8-bit microcomputer based on Arduino board and features a keyboard input, an output screen, and is able to load and run external programs.

DAN64 microcomputer

Current version of the project has the following features:

Composite video black and white output, 256 x 192 resolution, 32 x 24 characters (8 x 8 pixels font, code page 437 character set).
PS/2 keyboard support.
6502 virtual machine with system call interface to native code services.
Linear 64KB memory access from the virtual machine (256 bytes page zero, 256 bytes hardware stack, 6144 bytes of video RAM and 58880 bytes for user programs).
External storage support via audio in/out.
Integrated 6502 assembler and disassembler.
Basic shell supporting peek, poke, load, run, etc.