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The Fox Report Barry Fox’s technology column Cautionary food for thought W alk down any street and the chances are you will see a discarded single-use vape. Brightly coloured metal or plastic sticks, these come in a variety of nicotine fruit flavours which youth groups pass round to decide which they like best. Set aside issues of hygiene and the nicotine addiction issues that this encourages, and spare a thought for the waste. Each colourful vape stick contains a lithium-ion or LiPo (lithium polymer) battery along with a push switch, LED indicator, heater element and small reservoir of the flavoured drug. The batteries are pre-charged re-chargeables, with a standard 3.7V output. They are miniature versions of the larger capacity batteries used in portable devices such as mobile power banks, and they are churned out by the gazillion from Chinese factories: https://pemag.au/l/abyb Vapes vary, but the basic specification for a LiPo cell will be 3.56/3.7V, with a 400mAh capacity. As the maker’s websites may warn, these are ‘non-power’ cells, originally designed and intended for portable music players, Bluetooth speakers, wireless headsets, GPS trackers, baby monitors, dashcams, pocket games and doorbell devices. They are not intended for use in high-currentdrain devices like drones or power tools, although a bunch in parallel will surely pack more punch. Most important, these batteries are ‘dumb’ devices, with no charge control – just a positive and negative pair of thin wires soldered to flimsy cell tags. Trying to charge them direct from a DC supply, or shorting the wires, will almost certainly set the cell on fire. Although this very real risk will be well known to our readers, the world at large is generally, blissfully ignorant of lithium battery fire risks. Witness the number of house fires caused by badly designed e-bikes and e-scooters, and their cut-corner chargers. However, some consumer devices like mobile power banks are designed to work with a dumb battery; the plus/minus flying leads connect to a charge controller combined with in/out USB sockets. As a test – and one I really do not recommend you repeat – I stripped the dumb batteries out of half a dozen discarded vapes, roughly twisted together their positive and negative wires and crudely soldered the twist joints. (My days of fine-point micro-soldering are long gone). I then de-soldered and removed the single lithium cell from a mobile power bank, of the type now sold for enabling a few calls when the phone battery has gone flat. Finally, I soldered the bunched vape battery wires to the charge controller, adding a simple screw connector for the easy addition of a few more batteries if and when I collect them. I put the resulting kludge in a glass (nonconducting, non-flammable) container, placed it in the garden well away from the house and connected a low-current USB charger. The controller light first glowed red for ‘charging’ and later turned green for ‘charged’. I connected a mobile phone and it cheerfully signalled that it was charging. The whole caboodle is now in a halfwayto-good-looking plastic box (a discarded drill bit case) and is currently powering a portable radio designed to run from a phone charger. But it’s in a bathroom, close to a window for emergency ejection, and a limitless source of water for dousing. In reality, my experimental bodge is ‘probably’ as safe to use as a lot of battery packs now widely on sale, but I’m taking no chances. If you are tempted to exploit the many rechargeable lithium batteries now being discarded, please be similarly careful – work on the assumption that it may catch fire and position it so that this doesn’t set fire to your home… seriously. Meanwhile the fire (and pollution) risk these discards pose when bundled with ordinary house and street waste for landfill doesn’t bear thinking about, as this news report shows: https://pemag.au/l/abyc Words to the wise Phone theft has now reached epidemic level. Using one on a city street to get directions or take a call has become (left) Batteries from discarded vapes and a dead battery (blue) with soon-to-be-recycled connector/controller. (right) DIY chargeable recycled vape battery ‘power pack’. 6 Practical Electronics | September | 2024 My recycled batteries housed in the green case to power a radio. This is not safe and such systems should never be left unattended where a fire risk may lead to a house fire. Better still, don’t repeat my experiment! risky. Many thefts are ‘drive-by’. A thief on a bike races past and grabs. In cafes, thieves distract by waving papers and putting them down over anything valuable on the table. Bags are hooked away from under a seat. I recently lost my phone. It could have been pick-pocketed or more likely fell out of my pocket when I turned it off for a theatre show and stowed my coat under the seat. I had a spare phone – without a SIM – and making it a fully working replacement was a major pain which taught a lot of lessons, all of which I pass on because at least some may be new and useful to some readers. The location of Google and Apple phones can in theory be traced with Android/Google and iOS apps. But in practice it’s not much help to know that your phone is somewhere inside a scary block of flats. Mine showed as still at the theatre because I’d switched it off inside the theatre; it then disappeared altogether. The theatre ‘did not find it’. Realistically, unless you have lost a phone in a safe place like a friend’s house, when a phone’s gone, it’s gone. What matters is how easily you can recover from the loss, especially now that so much of modern life is locked to a mobile number, because it is unique to the owner. Apps such as Telegram and WhatsApp depend on mobile phone access – authorising matching apps on a desktop computer needs the phone. NHS appointments and reminders, and travel and event bookings are often attached to the mobile. You can use Android and iOS apps to make sure contacts stored on the mobile are available from another device, for instance on a home PC – but not so easily available that losing a phone means losing vital security, for example if the phone is in use when stolen. Do remember that some contacts may be stored only on the SIM, unless and until you copy them off the SIM. You won’t appreciate how much you rely on your phone, and the ramifications Practical Electronics | September | 2024 of losing it, until you have lost it – or set yourself a dummy run challenge. I store all sensitive data such as passwords with vital digits replaced by asterisks. I also make a hard copy of the data, also with asterisk replacements, and store that in a safe place. Paper can’t be hacked, and paper doesn’t need a device with a charged battery or mains power, and SIM to read it. None of this is foolproof. Bletchley Park could have easily cracked the asterisk system. But it buys time and encourages thieves to move onto an easier challenge. Emails can be accessed by the owner from multiple devices. Voice messages can be remotely accessed by dialling the number and keying in the voicemail PIN. You can also record a new greetings message which advises callers not to send texts to the lost number, and giving an alternative number to call or text. This is important because I know of no way to read SMS text messages without access to the lost phone SIM. Don’t do as I did and make the mistake of keeping other items – such as emergency money or a travel card – in the phone cover. The travel card can be remotely invalidated and a replacement obtained (at a price and with postal delays) but money is an incentive for a finder to take the money and ditch the phone. Otherwise, they face thanks for finding the phone and then questions on what happened to the cash. The phone networks have schemes in place to block and replace a lost or stolen SIM. Replacement may take a few days and may cost a few pounds. The networks can also block access to a lost or stolen phone when fitted with a new SIM. Wiping a password-protected phone clean without its passwords should be impossible, but don’t underestimate the creativity of the professionals who buy the phones stolen by street opportunists. The remote blocking system uses the phone’s 15-digit IMEI (International Mobile Equipment Identity) and may not work in some under-developed countries. A blocked phone can still be sold for spares, for instance to replace a cracked screen or failed battery. One practical word of warning. Don’t do as I did and take SIM loss and replacement as an ideal opportunity to change tariff or network or both. Changing network while retaining your old number involves use of the PAC (Porting Authorisation Code). The new network cannot do this without the SIM for the old number. The easiest way is to apply to your existing network for a replacement SIM. This SIM will come with a new number which the existing network will authorise, and then have to switch off and replace with your old number. Then you can progress to getting a PAC and changing network – if you still have the energy left to do anything. Meanwhile set yourself some golden rules. Carry your phone in a zipped pocket, use it in a doorway or shelter to avoid grab-theft from a racing bike or scooter, and make sure all essential passwords for digital living are easily accessible without your phone and SIM. All this is much easier to find time for when you have been through the logistic grief of losing a working phone. Internet radio While I’m on the subject of phones, here’s an idea which may be new to some readers. Internet radios are pricey, but the function comes free with a smart phone or tablet. Just install an app or browse for the station website. If you then connect the smart device to an amp and speakers, you have yourself an Internet radio. Some systems will be able to hook up to the phone or tablet by Bluetooth; older systems like hi-fi amps will have an analogue line-input which can connect direct to the headphone socket found on older mobile devices. It doesn’t much matter if the device screen is cracked, as long as it’s readable; if the device battery no longer holds much charge, just run it with mains charger. It’s no longer a portable device anyway. This makeshift Internet radio system works a treat – I’ve done it with phones and tablets, both Android and iOS, connected to a home hi-fi rig. I needed to do it because modern network/streaming amps have their own inbuilt Internet radio ‘tuner’, but this may not get some stations you want to hear. Using an external mobile is an easy way to bypass the inbuilt Internet tuner if you want or need to. PE Best of all, it’s essentially ‘free’. 7