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Coming up in Silicon Chip Altium Designer 19 review Advertising Index Altronics...................15,CATALOG Hot on the heels of the major update that was Altium Designer 18 comes this new major version of this Australian electronics computer aided design (ECAD) software. El Cheapo Modules – LoRa long-range digital modules These low-cost modules allow microcontrollers to communicate with each other even when they are hundreds of metres apart, or in some cases, even kilometres. And they’re pretty easy to set up and use, too. Facial Recognition Systems Ampec Technologies................... 7 Cypher Research Labs............... 8 Dave Thompson...................... 103 Digi-Key Electronics.................... 5 Emona..................................... IBC H K Wentworth.......................... 13 Is Big Brother watching us now? Facial recognition systems are already in use by Australian government agencies. Dr David Maddison explains how computer-based facial recognition systems are able to identify individuals in still photos, video and even in real-time. He then takes a look into the applications of such systems, both beneficial and nefarious. Hare & Forbes..........................2-3 Jaycar............................ IFC,49-56 Keith Rippon Kit Assembly...... 103 LD Electronics......................... 103 Flip-dot display This is one of the more unusual electronics projects that we’ve come across. It’s a dot matrix display that’s highly visible in just about any lighting condition and it’s driven by electromagnets formed from PCB tracks! It could be used in a practical outdoor alphanumeric display or a fun indoor display. LEACH Co Ltd........................... 19 High-current linear bench supply Mouser Electronics.................... 11 This power supply has very low ripple and noise due to the use of linear regulation. But it can still deliver plenty of current (>5A) with an output of up to 50V. Ocean Controls......................... 12 LEDsales................................. 103 Microchip Technology.................. 9 PCBcart................................... 27 UHF repeater Based on reader requests, this device extends the range for devices such as our 2015 Driveway Monitor which use UHF transmissions to send data from a remote unit to a base station. It can both extend the usable range and also solves line-of-sight problems caused by hills or obstacles that are in the way of the signal. Rayming Electronic Co Ltd........ 14 Note: these features are planned or are in preparation and should appear within the next few issues of Silicon Chip. The Loudspeaker Kit.com......... 10 The April 2019 issue is due on sale in newsagents by Thursday, March 28th. Expect postal delivery of subscription copies in Australia between March 26th and April 12th. Rohde & Schwarz.................. OBC SC Vintage Radio DVD.............. 25 Silicon Chip Shop......83,100-101 Tronixlabs................................ 103 Vintage Radio Repairs............ 103 Wagner Electronics................... 93 Notes & Errata Tinnitus & Insomnia Killer, November 2018: there is an error in both versions of the PCB. The 68kW resistor in the Pink Noise Filter (above and to the right of IC1) is connected to the wrong end of the 1kW resistor immediately next to IC1. This results in the pink noise being slightly louder than intended. This error will be corrected on RevC PCBs. If you have a RevB PCB, you can fix it by cutting the bottom layer track between the nearest pads of these two components and wiring the now free end of the 68kW resistor to the opposite end of the 1kW resistor using a short piece of insulated wire. Stationmaster Walkaround Model Rail Controller, March 2017: two 10MW resistors have been left off the circuit diagram, Fig.2. One connects from the +5V rail to pins 10 & 13 of IC1 while the other connects from pins 10 & 13 of IC1 to ground. The PCB overlay and parts list are correct. Also, because power indicator LED1 is connected to the supply before the bridge rectifier, it will only light with a DC supply that applies a positive voltage to either pin 1 of CON1 or the centre pin of CON2. On page 37, instead of 10kW capacitor, read 10kW resistor. Also, the cable connecting the two boards needs to be the type with its inner two conductors swapped or else speed control VR2 will operate in reverse. Finally, note that the MC14584 chip used in this project is hard to obtain; the more common 74HC14 can be substituted. 104 Silicon Chip Australia’s electronics magazine siliconchip.com.au