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Infrared remote control jammer This device was developed to preserve our sanity when our grandson or younger family members come to visit. They love watching childrens TV channels at high volume levels, resulting in an amazing amount of highly irritating sounds. The result is continuous cries of “turn it down”, only to have the volume slowly turned up again over the course of a few minutes. This device sends out a 15-second burst of infrared at around 38kHz whenever the volume up button is pressed on the remote control. This swamps the IR receiver in the television, stopping the volume increasing. To successfully turn the volume up, two buttons on the remote must be pressed first (in either order), then the volume up button. I chose the yellow and red buttons on my TCL brand remote. Note that as soon as another button is pressed, for example to change channels, the device reverts to jamming mode. I also had to disable the manual volume up button on our TV as our grandson soon worked out that he could turn the volume up that way! The circuit is simple – the infrared receiver and IR LED are both powered from the Arduino’s 5V supply. The receiver feeds remote control codes into digital input D11 while digital output pin D8 drives the IR LED via NPN transistor Q1, with a 270W base current limiting resistor and a 10W LED current limiting resistor. I built my device inside a plastic box and powered it from a USB power supply that goes to the same socket as the television, so the circuit has power whenever the TV is plugged in. The infrared LED needs to be reasonably close to the TV, and ideally hidden to avoid sabotage. The software code is commented to show where to enter the required infrared codes to suit other TVs. You will need to use the included IR decoder sketch (which I did not write) to determine the codes produced by your remote control. Both sketches are available for download from siliconchip.com.au/Shop/6/5821 Geoff Coppa, Toormina, NSW. ($75) POWER SUPPLIES PTY LTD ELECTRONICS SPECIALISTS TO DEFENCE AVIATION MINING MEDICAL RAIL INDUSTRIAL Our Core Ser vices: Electronic DLM Workshop Repair NATA ISO17025 Calibration 37 Years Repair Specialisation Power Supply Repair to 50KVA Convenient Local Support SWITCHMODE POWER SUPPLIES Pty Ltd ABN 54 003 958 030 Unit 1 /37 Leighton Place Hornsby NSW 2077 (PO Box 606 Hornsby NSW 1630) Tel: 02 9476 0300 Email: service<at>switchmode.com.au Website: www.switchmode.com.au May 2021  85