Archive for the ‘AVR/Arduino’ Category.
I did a teardown of a BK Precision 4011 5MHz function generator a few weeks ago. Like most of basic function generators in old days, BK 4011 does not offer frequency sweep as an option. What it does include is a VCG (Voltage controlled Generator) input, which essentially is just a VCO and it can be used in conjunction with an external sweep generator to generate frequency sweeps. Continue reading ‘Building a Sweep Generator for BK 4011’ »
Last week, I discussed the construction of a network-capable temperature and humidity sensor using SHT21 and ENC28J60 with an ATmega328P microcontroller. In this post, I will show the results obtained so far and the techniques used to chart the data. Continue reading ‘Temperature and Humidity Logging Over Ethernet — II’ »
I did a project on temperature/humidity logging a couple of years ago. In that project I logged the temperature and humidity readings in my basement lab over the course of a year. One issue with the approach I took back then was that the data could not be observed in real time because the logged data were written to an SD card and could only be retrieved once the logging process was done. Continue reading ‘Temperature and Humidity Logging Over Ethernet — I’ »
LM95172 is a 13 to 16 bits wide temperature range automotive-grade temperature sensor in a ceramic SOIC package. Besides its wide range temperature measurements capability (-40 Celsius to 200 Celsius), it can also be programmed to trigger over-temperature/under-temperature alarms and perform one-shot temperature conversation for low power applications. Continue reading ‘Arduino Library For LM95172 Temperature Sensor’ »
I bought a used Keithley 196 bench multimeter a few weeks ago. This is a 6 ½ digit 3,030,000 counts meter, capable of measuring voltages down to 100nV and currents as low as 100nA. It can also be used to measure low resistance with a resolution of 100 µΩ using 4-wire measurement. And because of the high input resistance on lower voltage ranges (> 1 GΩ), this meter is great for working with analog circuits where precision measurements are often required. Continue reading ‘Keithley 196 Firmware/Calibration Data Backup’ »
ADS1224 is a 24-bit delta-sigma analog-to-digital converter with 4-channel differential inputs multiplexer. This ADC chip offers a 20-bit effective resolution (6 to 7 digits of resolution in full scale), which makes it ideal in high-resolution voltage measurement applications. Continue reading ‘Interfacing ADS1224 With Arduino’ »
I picked up an AD9850 DDS module on eBay an couple of weeks ago and decided to build a MCU controlled DDS function generator with it to replace my crude frequency generator I built earlier. Continue reading ‘DDS Function Generator Build’ »
I built an I2C multiplexer shield using an Arduino prototyping shield from SchmartBoard a couple of weeks ago. The shield uses a PCA9548A I2C multiplexer and switch chip from Taxes Instruments. Continue reading ‘I2C Multiplexer Shield Testing’ »
I got a Syma S107G IR controlled helicopter for my son a while ago. This tiny remote control helicopter is a rather amazing toy. Not only its movement is very stable, but the rotor speed, forward backward movements and turning can be all proportionally controlled as well. I thought it might be interesting to take a look at its control protocol to see how things are done. And yes, I do have a video at the very end showing controlling the S107G using the reverse engineered remote control. Continue reading ‘Reverse Engineering the Syma S107G IR Protocol’ »
Microchip‘s MCP4821/MCP4822 is a low budget 12-bit digital-to-analog converter. MCP4821 is the single channel version whereas MCP4822 has two channels that can be latched simultaneously. Both chips have internal band gap references and can be controlled via SPI. Continue reading ‘Code For MCP4821/MCP4822’ »
Last year, I wrote about a simple digital metronome project. While the device worked pretty well there are a few changes that are to be desired. Continue reading ‘Digital Metronome — Revisited’ »
In this post I will show you a simple Zenner diode tester circuit, when coupled with a PWM generator it can be used to measure the breakdown voltage of Zener diodes. Or more generically, it can be used to measure the breakdown voltages (e.g. BVceo, BVcbo) of BTJ transistors. Continue reading ‘Simple Zener Diode Tester’ »
Last time, I discussed how to interface TI’s ADS1112 16-bit delta-sigma A/D converter with Arduino. Today I am going to introduce you to a set of easy-to-program A/D chips from Microchip. MCP3246/7/8 are a family of 16-bit Delta-Sigma A/D converters with an I2C interface. MCP3426 and MCP3427 both have two differential input channels, while MCP3429 has four differential input channels. The programming for all three devices are essentially the same, except for the number of available channels. Continue reading ‘Arduino Library For MCP342X’ »
ADS1112 is a 16-bit delta-sigma A/D converter. This A/D chip has an I2C interface, a 2.048V internal voltage reference and performs a self-calibration on each conversion. These characteristics make it very easy to work with an MCU such as ATmega328p. Continue reading ‘Interfacing ADS1112 With Arduino’ »
I got a used 250VA power transformer that was removed from equipment a couple of weeks ago. The transformer has a dual 10V AC output and a few auxiliary voltage outputs. The 10V winding is rated at 10A, I thought it would be perfect for a high current power supply project. Continue reading ‘5A Lab Power Supply With Digital Readout’ »