Posts tagged ‘Arduino’

Building a Constant Current/Constant Power Electronic Load

A while back I built a simple constant current electronic load using an aluminum HDD cooler case as the heatsink. While it was sufficient for a few amps’ load under low voltages, it could not handle load much higher than a few dozen watts at least not for a prolonged period of time. So this time around, I decided to build a much beefier electronic load so it could be used in more demanding situations. Continue reading ‘Building a Constant Current/Constant Power Electronic Load’ »

Interfacing TLV5620 With Arduino

TI’s TLV5620 is a budget 4-channel 8-bit DAC. While it is designed primarily for running with a power supply between 3V and 3.6V, it can be powered by 5V as well given its wide supply voltage range. With a TL431 voltage reference (2.5V), the DAC output can cover 0-5V with the RNG bit set. Continue reading ‘Interfacing TLV5620 With Arduino’ »

An Isolated DAC Using PWM Output

Arduino‘s (ATmega328P) PWM outputs via analogWrite can be conveniently turned into analog voltage levels through the use of simple RC filters. Since the PWM outputs are not isolated, using them to drive other devices directly could be potentially dangerous. This is especially true if the target circuit uses a higher supply voltage. Continue reading ‘An Isolated DAC Using PWM Output’ »

VFD Clock – Putting Everything Together

After I completed the filament driver and the circuit to drive the multiplexed VFD segments, it is time to finish the VFD clock project I had in mind earlier. Continue reading ‘VFD Clock – Putting Everything Together’ »

A DIY Vacuum Fluorescent Display Driver

In my previous post, I showed a simple vacuum fluorescent display filament driver built using a 555 timer and a custom hand-wound, center-tapped toroidal pulse transformer. And as promised in my earlier comment, I am going to show you the remainder of the VFD driving circuit here. Continue reading ‘A DIY Vacuum Fluorescent Display Driver’ »

Temperature and Humidity Logging Over Ethernet — II

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’ »

Temperature and Humidity Logging Over Ethernet — I

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’ »

Keithley 196 Firmware/Calibration Data Backup

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’ »

Arduino Dev PCB Using Seeed Fusion PCB Service

I have been mainly using perf-boards for my electronics projects. Since most of the stuff I build are not very complicated and are one-offs, using perf-boards has been more than adequate. With that said, I did find wiring the headers in my Arduino projects to be a big pain and depending on the number of break-out pins needed to be wired this could be quite time consuming and error-prone as well. Since I have heard many good things about Seeed Studio‘s Fusion PCB Service, I decided to give it a try. Continue reading ‘Arduino Dev PCB Using Seeed Fusion PCB Service’ »

Interfacing ADS1224 With Arduino

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’ »

DDS Function Generator Build

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’ »

I2C Multiplexer Shield Testing

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 Texas Instruments. Continue reading ‘I2C Multiplexer Shield Testing’ »

Prototyping With Schmartboard Arduino Shield Board

Neal at Schmartboard sent me a 0.65mm pitch Arduino prototyping shield kit a few weeks ago. I had meant to do a review right away, but then thought it would probably be even better if I built a real project with this board to see how well it worked first before sharing my experience with you. Continue reading ‘Prototyping With Schmartboard Arduino Shield Board’ »

Reverse Engineering the Syma S107G IR Protocol

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’ »

Code For MCP4821/MCP4822

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’ »