June 2010

PIC-based Musical Tuning Aid

You can tune almost any musical instrument, whether acoustic or electronic, with our PIC musical tuning aid. It can produce almost any note on the tempered musical scale (standard pitch) in any of the eight most common octaves, with accuracy better than ±0.08% or 1.3 musical cents. The selected note is either compared with that of a musical instrument using the ear, or visually using an 8-LED stroboscopic beat indicator.

Has mic / instrument input, line out, note and octave select buttons. Source code available for free download from our library.

DSP Musicolour (Part 2)

This fantastic advanced dsPICmicro-based light show is a full digital design offering a four-channel opto-isolated zero-crossing mains display.  It has direct stereo and microphone inputs for modulation of lights sequences, chaser modes, a 7×15 dot LED display and many more advanced technical features.

In Part 2 this month the full constructional details are supplied, in full colour with crystal clear diagrams. Much of the circuit is at live mains potential and therefore it is designed for assembly by skilled and competent constructors only. Part 3 next month describes the firmware and troubleshooting tips. Free source code (hex) file available from our Library.

PIC-based Water Tank Level Meter Telemetry Base Station (Part 3)

Last month we described the assembly of the basic and telemetry versions, along with installation instructions. In Part 3 this month the 433MHz telemetry base station is described. Designed to work with up to 10 water tank level meters, you can now monitor multiple water levels from a remote location. An option to operate an electric pump is included. A pressure sensor update is also published this month. Source code for the Telemetry Base Station is available for free download from our Library.

Also in this month’s issue:

• Recycle It! Our ‘rat it before you chuck it’ recycling specialist tackles the goodies that can be plundered from the innards of an electric bread maker, and a discarded fan heater (no less).
• PICkit 3 Debug Express Review – Read what our resident PIC expert thinks of this latest offering from Microchip.
• Circuit Surgery –  our specialist column handling readers’ own queries discusses techniques for smart battery monitoring. Dedicated devices such as the Texas UCC3957 and Maxim DS2740 are described.
• Interface – our periodic feature for PC interfacing applications lifts the lid on USB to parallel output interfacing
• Net Work – the Internet column –  takes a look at Google and the privacy concerns surrounding Google Street View: how to report a problem.
• TechnoTalk – mysterious blue spirals appeared in the atmosphere above Norway in December 2009. A US energy-beam experiment, a Russian missile or aliens?