Archive for January 2013

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’ »

Current Adapter for Low Current Measurement Using TS1001

For current measurement in the low micro-amp and nano-amp ranges, a feedback ammeter is usually an excellent choice (see Keithley Application Note 1671). Because of the very high gain of an Op-amp, the burden voltage can usually be ignored when using a feedback ammeter. Thus, the measurement results can be obtained much more accurately compared to using the shunt resistance current measurement method. Also, because of the near zero burden voltage, circuit that is sensitive to power supply voltage changes can be instrumented without affecting its operation. Continue reading ‘Current Adapter for Low Current Measurement Using TS1001’ »

Interfacing DS3232 RTC With MSP430G2452

I have used DS3232 RTC (real-time clock) in many Arduino based projects before. DS3232 utilizes a temperature compensated oscillator, which makes it far more accurate than devices like DS1307. In this blog post, I will give some code examples on implementing a digital clock using DS3232 and the TI MSP430 Launchpad. Continue reading ‘Interfacing DS3232 RTC With MSP430G2452’ »

Reading SHT21 Using TI MSP430 LaunchPad

SHT21 is a neat little temperature and humidity sensor from Sensirion and I have used it in a couple of my Arduino projects before. Given that the Vcc is 3 V for these sensors, interfacing with a 5V ATMega chip would require an I2C level translator (or alternatively, you could run the MCU at a lower clock frequency and use the lower Vcc). Since TI’s MSP430G2 series MCU runs at lower voltages natively, it is actually a lot cleaner to interface these 3V powered I2C devices. Continue reading ‘Reading SHT21 Using TI MSP430 LaunchPad’ »