Logic analyser

Top-bottom: frequency update, data, clock

First data byte magnified - 8 clock pulses send 00000011

Arduino 'Uno' board and logic analyser connected

I have a new toy to play with; the Saleae 24MHz 8 channel logic analyser. Looking for some signals to analyse with it, I programmed my Arduino board's SPI ( serial peripheral interface ) pins, incorporating the appropriate library code, to send frequency update pulses, 4MHz clock and 6 bytes of data to an AD9850 DDS chip. I was unsure how the SPI modes had been implemented in the library code. With the logic analyser connected I was quickly able to determine where my own code required modification so that the desired signals were obtained.

I needed 3 of the 8 available channels of the logic analyser. Previously I would have had to use my dual channel oscilloscope, viewing only 2 signals at once.

Digital thermometer

Arduino 'Uno' board and temperature sensor board

L: MCP2210 USB to SPI; upper R: LM35D; lower R: MAX6675

My fun with measuring temperature continues while waiting for the solder-mask stencils for reflow-soldering to be prepared. I have been using the LM35D temperature sensor chip. It doesn't require a thermocouple as the chip itself produces a voltage related to its own temperature, ( 10mV per degC ), and because the chip generates almost no heat, its temperature is nearly identical to that of its immediate surroundings. It's accurate to within about 0.5C. This time, because my DIY development board, ( MYDEV2 ), is otherwise engaged, I have been using my Arduino 'Uno' board with Atmel Atmega328P-PU microcontroller. I use the Arduino's analogue to digital converter to sample the voltage produced by the LM35D and then I process the 10 bit digital value to get the temperature for displaying. For no reason other than to use the second row on the display, I've also added a timer to count the seconds which have elapsed since the last program upload or reset.

I might make another for use as the workshop's digital thermometer.