Bad science... ...and good
Techno Talk Mark Nelson
Fire is a good servant but a poor master. The same can be said for science in general and electronics in particular, as you’re about to see.
B
y and large, we do not adopt
many new German words into the English language. That said, one that I currently have in mind is Schadenfreude, which has no direct one-word equivalent in English. In a nutshell, it means ‘taking pleasure in someone else’s misfortune’. Needless to say, mocking the less fortunate is not the policy of this magazine but on this occasion, I simply cannot not resist drawing your attention to a strange lapse in another, highly regarded, publication. First, please see how much ‘bad science’, halftruthery and outright disinformation you can spot in the following advertisement. ‘Save up to 25% on your electricity bills by installing a single-phase voltage optimiser at your home. In-line with CE regulations, most of the UK’s electrical equipment is designed to operate most efficiently at 220-230V. For historic reasons, our electricity is supplied to homes at an average of 242V but could be as high as 253V. It is a little-known fact that the more voltage you apply to an appliance the more energy it consumes, costing you more and shortening the life of the device. By matching your voltage supply to pieces of equipment it is possible to make a substantial energy saving and prolong the life of your household appliances. An Eco-Max Home Voltage Optimiser will reduce any excess voltage, leaving you with lower bills and lengthening the life of your electrical appliances. The ECO-Max Voltage Optimiser reduces your carbon footprint and saves you money and helps your electrical appliances last longer’. Wow!
Too good to be true? People on web forums are not fooled easily. Crucially, the device may well reduce your instantaneous power consumption, but only in terms of the rate of energy usage. It will not reduce, and may even increase, total energy used. Things like kettles will take longer to boil. Incandescent lights will use less power, but will be pointlessly dimmer. These optimisers will make no difference to the power consumption of anything containing a switch-mode power supply 10
or which are designed to absorb power until a specific function has been achieved (central heating). These devices, along with power factor correctors, do have a place in specific industrial environments, which are metered very differently to domestic consumers. But in an ordinary house? I don’t think so. So where does Schadenfreude come in? The ‘ethical products’ advertorial containing this ‘information’ appears in the 20 March issue of New Scientist magazine, which has long crusaded against ‘bad science’. At least this slip demonstrates that the magazine’s editorial and advertising departments operate independently!
Another way of saving electricity? Yes, I am obsessed with circuitry that works without batteries or mains power. This month’s clever stuff does that, but it’s not exactly free, because you have to buy special parts to make the setup work. Nevertheless, there’s no ongoing cost once you have made the initial investment. Energy harvesting is the ‘magic’ that makes this possible. ON Semiconductor (www.onsemi.com) is the innovator here and power switching for smart homes and buildings is the name of the game. In a nutshell, harvesting ‘green’ dynamic energy from the movement and force applied to a press-button switch is how the setup achieves significant cost savings. It does this with a wire-free Zigbee connection to offer unparalleled flexibility for deployment within buildings, requiring no hardwiring, zero maintenance hassles and no battery replacement or disposal. It gets even better. You have the flexibility to install a switch without cabling anywhere you want, and it will fulfil its function over the entire length of its service life without maintenance or battery changes. In contrast to hardwired data cabling, the self-powered wireless switch is also attractive for building services because it is easy to retrofit. For example, you can install new light switches without having to cut any holes in the wall. The system is not only for homes and offices, but also has great potential for industrial automation, particularly when the time
taken to lay cables is disproportionate to the application. Here again, the energyharvesting wireless switch serves as a cost-effective, battery-less alternative to cable-based microswitches.
Green Alliances A developer’s kit is available for anyone planning applications for these green power modules. In the kit is a Zigbee Coordinator USB device, which interfaces with the Strata Developer Studio (a cloud-connected development platform), plus two energy harvesting nodes, which act as Zigbee Green Power Devices. Pressing the switch on either of these devices generates energy that is used to power the SOC (system-on-chip) 2.4GHz transceiver device. This also has 640kB of embedded FLASH memory for program storage, along with 48kB of RAM for data storage. The energy harvester itself comprises a simple diode rectifier bridge, a clamp and a small 56µF storage capacitor. No EMC suppression is required, thanks to the low energy generated by the switch. To make these applications truly ecofriendly, you need wireless protocols that are compatible with the low-power nature of the switch elements. Available RF protocols include Bluetooth Low Energy and the Green Power option promoted by the Zigbee Alliance (http://bit. ly/pe-jun21-zgb). More at http://bit.ly/ pe-jun21-ons Whether or not this technology eventually makes it to the mass market or becomes available to hobbyists is unclear. Currently, ON Semiconductor is promoting the concept to OEMs, but it’s something that we shall be watching.
And finally... (at last) The UK’s Information Commissioner’s Office (ICO) and OFCOM have recently outlined a joint plan for tackling nuisance and scam calls for 2021/2022. This follows a surge in complaints from September/October to December 2020. OFCOM saw an 83% increase in the number of complaints compared with the same months in 2019 – details at: http://bit.ly/pe-jun21-ofcom Practical Electronics | June | 2021
