Extend Your DAC Resolution

IF you have used any of the microcontroller, you must have gone through the pain of limited DAC resolution which at some point of time must have forced you to use an external DAC, which is a little complicated to code. You can obviously extend the range of the DAC by using a sigma-delta converter on the software side but it can be a bit slowly. To extend the DAC, a LTC1665 8-bit 8-channel DAC and a 8-bit 6-channel digital potentiometer with a nominal resistance of 10K is used. Since the current flowing through the potentiometer is in the sub-µA range, a precision rail-to-rail opamp (AD8603) is added as a voltage follower to ensure the accuracy of the voltage divider. The resolution is extended by using two DAC with a potentiometer using which we can adjust the output voltage continuously. If the potentiometer is replaced by a digital one the number of bits at the output is effectively the sum of the DAC resolution and that of the digital potentiometer. The effective output is that we have a 16 bit… Continue reading

The dsPIC-Based Laser Light Show Controller – It’s Showtime!

If you always fancied about the laser light shows, but you’ve no ideas how to develop one for yourself, then you must pay attention on today’s topic, as it’s about the dsPIC-based Laser Light Show Controller! This dsPIC-based Laser Light Show Controller can also be known as an arbitrary waveform generator (ARB). For your information, the controller will allow vector patterns to be stored in flash program memory or uploaded from a PC in a vector format. The analog output via two 14-bit DACs has being fed to a commercial analog driver board and two high-speed galvo scanners. For the project, you need to use a Microchip dsPICDEM starter demonstration board featuring a 30F6012 processor chip. The best things about this board is it already has a prototyping area which is populated with the DACs, two connectors, voltage regulators and basic I/O circuitry (an RS-232 interface), where it simplifies the construction of the system. Theoretically, in a basic laser light show, there will be a laser beam is deflected by two galvanometer scanner heads, where each of them moves a… Continue reading