Faraday Fun

Signal-blocking Storage

Daniel Koch

Issue 43, February 2021

A signal-blocking phone storage box for learning spaces, social programs and those wanting to avoid distractions.

Managing device dependency and the mental health issues of social media is becoming harder and harder for those who work with young people.

There are a variety of reasons someone would want to block mobile phone reception. Many are rooted in unfounded conspiracy theories, poorly conducted or reported studies, or misguided interpretations of often real but incompletely documented science. There is also some genuinely concerning evidence of the negative effects of certain RF frequencies in certain situations, so that perspective cannot be dismissed.

Turning on modern phones is getting to be quite a process, approaching the start-up times of many computers, complete with sign-in requirements. In situations where you may legitimately want to be invisible for a while, sometimes shielding the phone is a better option. The same may apply if you have a need to move around and away from sensitive equipment regularly.

There are other contexts where it is reasonable to want to stop all phones or devices from having connectivity. These are often situations involving young people or children, such as classrooms. It also applies to youth programs run by community or religious organisations. In both cases, devices can be both a help and a significant distraction to what is meant to be going on. However, there is more to it than that. Any teacher, youth worker, or volunteer can confirm that the level of communication among young people is unprecedented, and there is a distinct negative tone that is always present somewhere among a group. This may be mental health issues arising from unrealistic media stereotyping, through to outright cyberbullying.


I have personally had conversations with parents of students I was teaching, where students as young as eight years old were being bullied or were involved in bullying over electronic communication. This phrase means both social media and messaging systems, which are different but related categories. At one school with one particular year group, the whole group was being spoken to more than monthly and individual students on almost any given day. The effects are real too, with anxiety, damaged self-confidence, serious depression or even worse being not uncommon results. Because of this, many adults involved with young people seek to limit device use for managed periods of time. At the very least, this provides some respite from the effects rather than actually solving any problems on its own, and is always part of a bigger strategy.

In the youth group I spend my own Friday nights at, I have seen the use of devices increase as the main cohort gets older. Most in the group are now in the senior years of high school. We have always sought to have the young people not use their devices during the program time, or at dinner where we encourage face-to-face socialisation without distraction. In the past, this was achieved by having those students with phones deposit them in a shoebox that we had marked for the purpose, at the beginning of the formal session. They kept their phones on them right up until it was time to begin the activities, and were never made to surrender them on arrival. The phones were then locked in the office more as a guard against theft while unattended than to keep the phones from the kids. The building is in use by other groups and the office is not visible from the area that we regulate as a child-safe space where only those cleared can enter.

This worked when there were fewer phones. However, something happened besides a significant increase in the number of phones. Relationships among those at the youth group are good, but some have worries brought in from outside. I had been aware of one particular young person who had been experiencing significant bullying from school, which was primarily over social media and instant messaging apps. Generally, when the phones are taken at the beginning of the night, we see visibly the anxiety be pushed away for a while as the session progresses. However, this person was becoming more and more anxious and clearly upset.


What I did not realise at first is that this person had received a smartwatch for their birthday. Although most smartwatches can read messages (some of the early ones could not scroll, only preview), this was one of the models becoming common more recently, that could use the touchscreen as a one-letter-at-a-time writing pad to respond to messages. Although the phone was locked in the office, this person had Bluetooth connectivity and communication via their wrist. While only the most naive of people think that this kind of negative social interaction can ‘just be ignored’, it was still surprising to see the extent of the power this situation had over the person it was directed at.

This led me to think about revising the ‘phone box’ situation. I was already thinking of building a box with individual padded pockets for physical protection of the phones, before these complications arose, because of the number of phones now being placed in the box. They were just being dumped on top of each other and the possibility of damage was increasing. We cannot just ask the young people to turn their phones off because there is no way to regulate it (we can’t tell at a glance if it’s the whole phone or just the screen that is off), and there are reasons to keep them switched on.

Mobile phone jammers are out of the question, not only because they’re illegal but also because the leaders and staff present have their phones on their person for emergencies, calls home, and communication between spaces while maintaining supervision and child safety by staying present. We cannot leave a room to speak with another leader elsewhere. In addition to that, both the fire alarm and the emergency help system the building has (think medi-alert for older people but a building-wide, hardwired, back to base dialler system) have SIM card/3G backups in case of landline failure. Lastly, other people use the building.

While we’re on that subject, we don’t consider it unsafe to ask young people to give up their phones, because any event which defeats all of the above safety systems and the landline phones around the building would be so catastrophic that the issue is irrelevant. In addition, all parents have leader and building landline contact details just as would have been the case before so many young people had devices.

What was really needed to deal with these issues was a way to screen the phones from the RF signals they need to communicate, rather than disrupting or swamping those signals or having the phones off. While we have all seen images or videos on the internet of people wrapping phones (and hats, windows, and whole houses) in aluminium foil, I didn’t think that was really going to be adequate. So, the research began.


A Faraday cage or shield is a way to screen electromagnetic signals and effectively eliminate them. It is often seen in the movies as a cage made of bird wire, on posts off the floor, in a basement or warehouse with surveillance equipment or computers in it. The reality is that it can be anything from a solid metal box, to a cage made of chain link fencing.

Without getting into a chemistry lesson, all materials have a number of electrically charged particles in them. Some are positive, others negative. In most materials, these are balanced under normal circumstances. Some materials are conductors, because their negative charges (the electrons) can be made to move along from atom to atom by an external force. Even so, many materials can be given a charge, even if they are not conductors. Styrofoam is a great example.

Faraday shields and cages are invariably made of conductors. They are, electrically speaking, hollow conductors, not a bunch of conductors with joins even though they may be physically constructed this way. This means that electrically, they are the same as a hollow wire, or hollow block of metal, even though they may be physically made of sheets joined together or wires woven together into a mesh. The overall form of a Faraday cage or shield is a conductive surrounding for a device or piece of equipment with no gaps in it.

When a charge is brought near the conductor of a faraday shield, the charges within it move so that they are opposite the charge which caused them to move. In other words, a positive charge outside the shield will cause the negatively charged electrons to gather on the outside of the conductor, leaving a positive charge inside the conductor. This cancels the charge’s effect inside the conductor. That’s ok for static (unmoving) charges, but what about electromagnetic waves (EM waves) like radio signals? The same applies, because the changing electromagnetic field induces a charge in the conductor, but it changes backward and forward at the same frequency as the wave does. In this way, Faraday shielding will cancel out EM waves.

Credit: National High Magnetic Field Laboratory /

Additionally, the thickness of the material matters. Charges accumulate on the surface of a conductor, and alternating current (and correspondingly, the alternating inherent in electromagnetic waves) causes current to flow on the outside of a conductor. The higher the frequency of alternation, the closer to the surface the current will flow. This means that for lower frequencies, shielding material must be thicker. The formula to calculate it is way beyond the limits we have set ourselves for publication, but you can find it by researching ‘skin effect’ if you want to. For pure copper sheet, skin depth at 700MHz is 2.46 micrometers, or 0.00246mm! It only gets less from there. For aluminium, the depth is 3.09μm. Kitchen-grade aluminium foil is generally 0.02 to 0.04mm, over ten times the depth we need.

There are differences between Faraday shields and Faraday cages. The chief visible difference is that a shield is solid while a cage is perforated. Cages may be made of metal sheets with holes in them, or from wire mesh. This has some effect on skin depth considerations but the biggest issue is that any holes must be smaller than the shortest wavelength that is to be excluded. This is not an issue for foils but it is for meshes, and must be considered with any material when making joins and other gaps during construction.


Since we’re dealing with wavelengths when discussing and making Faraday shields, and to understand where 700MHz came from above, it seems appropriate to cover a bit of history of mobile phone frequencies in Australia. Wavelength is related immediately to frequency, after all. This is far from a complete history. We’re interested in what frequencies were used and when, rather than in a total history.

Australia’s current and recent past mobile phone frequencies somewhat mirror the rest of the world, although some details differ. This is why many overseas phones don’t work here. These are very minor differences, as manufacturers wouldn’t find it economical to make completely different phones for a market as small as Australia’s when compared to other markets. In the main, the international names carry over, too, but with some differences and the generation names like 3G, 4G, have not always lined up around the world. This is because the ‘G’ labels are really for marketing and are not the names of the technologies used.

Australia’s first mobile phones were completely analogue car-based devices weighing up to 14kg and costing an amount that rivalled, with inflation, as much as some of today's budget cars. Some commentators have called this system ‘0G’.

The first mobile phone network to feature truly hand-held phones was 1G, called the Advanced Mobile Phone System (AMPS). Telecom’s first handset was over $4000 and the first call was placed in a publicity display in 1987. This system used a band around 800MHz, with analog transmissions in a paired arrangement like two-way radio. One frequency out of the band needed to be allocated to each call, limiting the number of connections to 300 per tower. Quality wasn’t great but became better as the hardware improved.

The first digital system to be used in Australia was GSM, which later came to be known as 2G, as it was the second generation along from the older AMPS system. GSM operated initially on the 900MHz band, and was offered initially by Telecom, as Telstra was known until 1995. This system was the first to use a SIM card, and the first to enable text messaging. SMS (Short Message Service) was designed at one hundred and sixty characters so that it could fit into part of the system used to send phone traffic control data, when that data was not being sent.

Later on, the 1800MHz band was added to the GSM system, and it is this format that became known as 2G. 2G coverage was not perfect, however. In rural areas it was outright poor. Australia then adopted the CDMA standard, which was a digital transmission system using the older 1G band and much of the transmission hardware. This system was closed down in 2008 to make way for expanded 3G services, except for Christmas and Norfolk Islands, where it is still used and perfectly adequate for the circumstances.

3G was first introduced in 2003, and used a combination of CDMA and GSM systems, but with enhanced protocols delivering faster data, more bandwidth, and better voice clarity. 3G evolved over time as well, adding an 850MHz band to the mix, Telstra’s NextG.

The big shake-up hit with 4G. This system uses multiple bands, although 2G systems and onwards had made use of two. 4G is delivered in Australia on Long Term Evolution (LTE) technology, and was introduced in 2011. Bands used are 700MHz, 850MHz (Vodafone only), 900MHz, 1800MHz, 2100MHz, 2300MHZ (Optus internet products in certain areas), and 2600MHz. 4G devices choose the best available for their needs at the time, with higher frequencies providing more bandwidth and faster data, and lower frequencies providing better range and obstacle penetration. This is why sometimes you can get a perfectly clear voice call but your internet buffers.

This means that when designing a Faraday shielding system, absolute signal blocking will only occur if the highest frequency is taken into account. Add to that Bluetooth, which operates on the 2.4GHz band and emerging 5G technologies up to 3500MHz (currently, but higher in the future), and it becomes practical to simply opt for the smallest mesh size obtainable.


Frequency is the rate at which a wave cycles. It is the number of complete cycles in one second, and is measured in Hertz, abbreviated to Hz. The decimal multiplier system applies, so you will have seen MHz above. M designates Mega, or 106. In other words, one million. 700 MHz is seven hundred million cycles per second.

Wavelength is the physical distance between identical points on a wave. In electronic terms, this is often the time between the crossing of the zero point when a wave is rising, but in other fields is often the time between peaks or troughs. Older, low-frequency communication waves had wavelengths often in metres. That won’t be the case for our mobile phone frequencies!

This is why some Faraday cages can be made from chain link fencing or bird wire. It all depends on the frequency or frequencies that need screening. The higher the frequency, the smaller the holes must be. Generally, sheet metal provides better attenuation (reduction) than wire but metals are expensive, especially in big sheets. They are also heavy and hard to handle for building rooms. Foils are a better choice here but again depending on skin depth issues, may not be suitable.

I now knew the minimum required thickness for the material based on the skin effect, and it is far less than any material I will be able to work with, but what about holes? I needed to know the wavelength to find the largest hole that can exist in the material. The frequency of a wave is found by the formula:

f = C/λ,

where λ (the greek letter lambda) is the wavelength and C is the speed of light. By the way, that is 299 792 458 metres per second in a vacuum, but the figure varies in other media. In air at sea level, it is 299 702 547 m/s. The scientific constant, however, is generally the speed in a vacuum. The result will be in Hertz.

Rearranging the equation, the wavelength can be found from a known frequency.

Use λ = C/f.

For the highest possible frequency (which will have the smallest wavelength) of 2600 MHz, the number must first be converted to Hz, giving 2 600 000 000 Hz. Note that the band does go higher than exactly 2600 MHz, but let’s do the calculation first.

λ = 299 792 458 / 2 600 000 000 = 0.115304791.

Rounding off, that’s 0.115305 metres, or 115.305 millimetres.

However, this isn’t all that is needed. The rule of thumb gleaned from those who build and use Faraday shields for a variety of purposes and wavelengths is that any holes in the cage or shield, be they regular perforations or single entries, should be less than one-tenth of the target wavelength, but there are so many other factors at play and pathways available that it is better to just eliminate any holes.


During research, some people had reported success with aluminium foil as a mobile phone blocker, while others had not. The same can be said for the faraday fabrics, too. I had chosen not to use foil because of its fragility, but it was worth experimenting with during the bench testing phase. The key in any case is completely surrounding the device.

One option is simply a metal toolbox. As long as the gaps are no bigger than 11.53mm (one tenth of the wavelength, it should work. Other options which presented themselves were wire mesh, and metalised fabric. On this last option, there is a huge variety of options and even more opinions and experts. None are available retail, so I went online. There are online sellers and there are sites like eBay and Amazon. I became aware that some fabrics are meant for clothing, and as such are only a metalised appearance. Genuinely conductive fabrics are still around, so I ended up with one that had lots of fine copper woven into it along with polyester as a flat cloth, and another that had a silvered appearance with a grid woven in, a lot like Ripstop Nylon but on a smaller grid.


The first step was to decide how to run the tests. We don’t have EMF meters at DIYODE, and they’re quite expensive. We couldn’t justify buying one just for this. Additionally, if the aim is to sever connectivity, then exact, scientifically-measured numbers are irrelevant. I opted instead to use a Bluetooth speaker, and a landline phone to call the test mobile phone. If the connection with the speaker was lost and the phone could not be called, the aim had been achieved.

I wanted to test aluminium foil just to see what effect it had, along with two legitimate candidate fabrics: A copper woven cloth, and a silvered metalised fabric of unknown metal. I also used a metal toolbox, and an army ammunition liner for fun.

These are made with thicker steel and at a much tighter tolerance than the toolbox, and with the aid of a thin rubber seal, are waterproof. It should be noted that the toolbox had four holes in it where rivets for an internal cantilever shelf had been removed. They ranged from 5mm to 9mm, along with slight gaps at the bottom of the box.

The test procedure was to lay the phone on the bench, connect the speaker and play some music, then call it from the landline. At first, I just laid the foil or fabric over the phone. This set of tests was labelled ‘open’, as I also placed the phone in the toolbox and liner with the lid open. Then, I repeated the test with the phone completely wrapped in the foil or fabric, or the box lid closed. This is the ‘closed’ column. Testing WiFi involved messaging apps used while mobile data was turned off, with WiFi the only connection.

The toolbox on its own provided very little screening. I did notice that the music was buffering and stopping with the lid closed, so the higher-bandwidth 4G signal was having trouble, but the speaker makes a noise when Bluetooth connection is lost, and it never lost the connection. This is in contrast with the single layer of fabric, which did cut the connection. The test distance for Bluetooth was five metres. With the fabrics, however, things were different. No connectivity at all was found. The phone sat on top of the bundle of material, with only a single layer over the top. This allowed me to not cut the material before I had the box shape worked out. When the phone was withdrawn after the test, it was searching for the old 3G backup signals and even trying HSDPA.

One standout point is that even a small hole in the fabric allowed connectivity. Either the maths above is wrong (despite the fact that it checks out from quite a few sources), or the gap was indeed bigger than 12mm in one dimension. In other words, the hole where fabric rolled around a corner may have looked like a 5mm round hole, but may in fact have had a half-millimeter gap where the sides sat together. I’m still not sure. What I did do was decide to make sure the box was as continuous as possible.

From these results, I decided to line the toolbox with the copper fabric. Both fabrics did the job, but many of the young people involved are into the ‘rose gold’ look at the moment, and while true rose gold is expensive, many items are actually just copper labelled as rose gold. Additionally, only one layer of fabric seemed necessary. It had to be continuous, however, so the lid would have to touch the lining of the rest of the box. Seeing as the box was going to be lined with cushioning foam, I elected to line the lid as well, and thereby provide some pressure to maintain contact.

The Build: Making The Box

After a bit of brainstorming, I decided to line the toolbox with EVA closed-cell foam, and cover the foam with the copper fabric. Dividers were to be made of foam-core board, with foam and fabric layers over them. The foam alone did not have enough rigidity (which would defeat its cushioning purpose) to form a divider on its own. With foam-core, I could screw through the side of the box to secure the dividers. I toyed with the idea of glue, but that depends on the bond between the fabric and the foam underneath, rather than being directly anchored to the box sides. The other reason for using screws is that the most suitable adhesives are contact adhesives, and the dividers need to be slid into place. That isn’t possible with contact adhesives.

The first step was to drill the rivets holding the cantilever shelf in the box. I was originally going to remove the handle because I wanted to paint the box, not only because it was a similar red colour to fire equipment and some of the older attendees were beginning to learn about site safety, but also for the sake of it. I wanted a colour that was less negative in semiotic terms, and greens and blues tend to be the most useful colours in the semiotic system. I chose forest green for no other reason than it reminds me of British Racing Green sports cars, and some of the young people have the same interest. In the end I left it, as reattaching it securely was going to be an issue.

I visited my local rubber and foam shop, and bought a whole sheet of 6mm EVA foam. It was cheaper to buy a sheet than have it cut to a square meter anyway, and I wanted room to experiment. This means I needed to take 12mm off the internal length of the box, then figure out how many dividers I could fit. These would be 6mm plywood with 6mm of foam on each side, giving 18mm total thickness. I had looked at multiple phones and decided that 20mm was a minimum width for the pocket, to accommodate the cases and selfie rings many of the young people have on their phones.

The internal box length for the toolbox I had was 458mm. I took 12mm off for the end foam, and 20mm for the first pocket, leaving 426mm. Dividing this by a total of 38mm for each pocket/divider combination, I could fit 11.2 dividers. Of course, the 0.2 remainder will be distributed across the pockets. That leaves 12 pockets in total. With a box width of 190mm after foam was added, this still left plenty of room for two smaller phones to fit into each pocket side by side, or one bigger phone for those who have them. To get even spacing, I divided the whole 458mm length by 12, as this would yield 12 even spaces that would have 6mm of foam on either side of them, with eleven dividers.

After marking out the equal distances, I added two horizontal lines at nominal values, so the two screws in each side of each piece of foam-core were in nice straight lines. It would be unlikely that I would be able to hide these once the box was painted, so they had to be neat. Then I drilled clearance holes for 4Gx20mm screws. These wood screws are countersunk and would sit slightly proud. At this point, I was thinking of covering them but wasn’t sure what with.

Even though I drilled the holes carefully, in 1mm increments, with cutting fluid and at an appropriate speed, I had significant deburring to do on the inside.

After deburring all the holes, I thoroughly cleaned the box to remove any oils and residues, and took the box outside for a coat of paint. I also masked carefully around the handle, as I had decided to not remove it. Painting under it would be a challenge but less so that attaching it afterward if it were removed. The box will carry a reasonable amount of weight when full, and glue may not hold. Rivets were out of the question, as were bolts, because both protrude too far. The flat rivets used originally are commercial and require special tooling not accessible to me.

While the paint dried, foam-core was marked and cut to the internal width of the box, minus the 12mm for foam at the box sides. The strips were then cut to just shy of the height of the box, to accommodate the lip at the top. Remember, the dividers exist for physical separation and protection of the phones. They were not part of the Faraday shielding overall, they were just bonus screening if anything, and were likely to be ineffective. There is no way to make the dividers reach the top when the recessed lid is hinged, without cutting the corners. Without this, the arc created by the path of the lid rotating around the hinge collides with the dividers. To fit with straight divider sides, it would either have to be a flat lid, or a drop-on lid, and it was neither.

Now it was time to cut the foam. The internal net of the box was marked at one side of the sheet of foam. This was the floor and four sides, not the lid. Two sides are slightly shorter to accommodate the 6mm thickness of the sides that butt up against them. This foam can be cut with a snap-blade knife on a suitable surface, and that’s exactly what I did. An old cardboard box can suffice, but I used a scrap of MDF.

The same process was repeated for the lid, but I found in a dry run that the 6mm foam was too thick for the lid to close. On closer inspection, I noticed what should have been an obvious point: The lid overlaps the body of the box by about 5mm, and the tolerance is only a couple of millimetres. This means that the foam for the lid has to stop at the line where the upper edge of the box will meet the lid. In this way, the conductive fabric can be wrapped over the top and bottom edges of the foam in the box and lid respectively, and the pressure used to create an electrical connection.

The least appealing steps of the process involve the spray contact adhesive. This stuff, if the surfaces to be joined to not line up straight away, is generally impossible to remove. The first use of it was to bond the fabric to the foam for the inner lining of the box. However, if it is applied to one surface only, the bond is weaker. It would be strong enough for this purpose but removable with effort. I sprayed the foam cutout for the box interior, allowed the glue to gain a slight tack, and laid the foam onto the back of the fabric. After it had dried, I trimmed the edges of the fabric, leaving enough to cover the sides as well to achieve electrical contact, and a large flap for the lid. A little more glue decanted into a cup and brushed on helped here, but don’t apply so much as to interfere with electrical connection.

Next in line were the dividers. These had to be covered with foam first, then fabric. Foam was cut so that the edges of the foam board substrate were not covered, and glued on with contact adhesive. After this dried, the fabric was glued on and the edges trimmed close with a knife. Scissors don't get close enough, and leave a staggered edge anyway.

The inside of the box was sprayed with contact adhesive and, when it had gained a tack, the foam/fabric laminate was applied in such a way that the fabric edges were pressing against each other. The same was done for the lid, but the fabric at the hinge side is one continuous piece. This necessitated two applications of glue to the lid: one to fix the foam down, and another for the fabric to the foam.

With the foam dry, the dividers were placed and screwed through the sides. It was helpful to have the centres marked first, so alignment could be verified before screws were installed. Because the screw holes were covered in foam and copper fabric, alignment was achieved by marking the fabric inside the box with a graphite pencil. The dividers are a tight fit, so they had to be inserted at an angle, and then twisted into place with the fabric under slight pressure. One side was screwed into place first, then the box turned over and the other sides of the dividers aligned and anchored.

I decided to use copper tacks to cover the countersunk screws. I cut the pins short and glued them into the screw head with hot melt glue so they could be removed if needed. I added some over the rivet holes from the shelf as well.

That completed the box. I’m not sure I like it in Forest Green, and I may cover it in old leather or timber veneer one day, aged to look old. That’s the image in my head now that I’ve seen the copper tacks around the box. I was yet to test it with a full set of phones at this point, but I was reasonably confident that all the areas of fabric were in close contact, and if there were any issues, copper tape can be used to make joins. However, it must be copper tape with conductive adhesive, and not all copper tape has this. The other alternative is conductive paint.


With the box complete and the paint and glue all thoroughly dry, it was time to test the theory. Three different phones were placed in the box together, and calls were placed from the landline phone in the office. At first, two of the phones rang, but it was quickly realised that the lid was not closed properly, leaving a gap of around 9mm along the entire length of the box. With the lid fully closed, the call, message, Wifi, and Bluetooth tests were all repeated. With a few tweaks to where the fabric edges met, including adding a little with some of the conductive fabric tape supplied with the fabric (silver in the images), the desired result was achieved.


For child protection reasons, I can’t show you the results from the first night I took the Faraday phone box to the youth program, but it involved many scowls, fervent tapping of and fiddling with smartwatches, and an eventual realisation that the new phone box was in fact much more than prettier and softer safe storage. It also involved much complaining and whining, then a slow realisation that maybe some downtime from the social media and communication environment isn’t such a bad thing. Some remained upset, but welcome to life.

I want to reiterate that I do not think for a second, nor does any other leader at this youth group, that taking phones away for an hour or two will outright solve any problems. We have regular discussions, instructional sessions, and thinking workshops regarding the dependence on and influence of social media and communication, along with toxic friendships and relationships and the problems those can cause. We also provide counselling to specific young people as the need arises. Along with these things, the Faraday phone box has become another tool in managing the welfare of our young people for the time they’re in our care.

Of course, there are other contexts besides youth group settings. The Faraday phone box might be of interest in classrooms too, particularly in primary school where phones are usually placed in the office or in a storeroom cupboard during the day, or at the front of the classroom in high school settings. In both these situations, it is important that the students understand they are placing their phones into the box until the end of the lesson or day to maintain the learning environment, rather than their possessions being ‘taken’ from them. On that note, the young people at the youth program do the same, placing their own phones in the box, albeit with lots of repeated requests in some cases.

This may seem a trivial or overly sensitive point but young minds perceive situations differently. I employ the same strategy when confiscating objects in classrooms when I am teaching. Unless they’re dangerous, any items taken go on top of the shelf at the side of the room, out of reach of younger students but not into my possession. I quite often say, after explaining that the item is a distraction to the owner and other students, that “I’m not taking it, I’m just moving it out of your reach where it won’t be a problem for you”. This helps make sure I cannot be accused of stealing, helps maintain a witness base in the other students, and eases the perception of having the item stolen. This feeling affects students with prior or out-of-school experiences but it’s a strategy that has served me well. Emphasising that the phone box as a way of keeping the kids’ possessions safe while removing the distraction follows the same principle.