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Micro Review: BlitzWolf BW-F4 Bluetooth speaker

I listen to dozens of podcasts, and I usually have one playing while I’m working on electronics projects in my workshop. The speaker in my iPhone is ok, but I wanted to get some kind of external speaker to give it a bit more volume.

BlitzWolf kindly sent me a BW-F4 Bluetooth speaker to use in my workshop. I’m not really into music (I’d rather spend my time listening to something that teaches me new things) so I can’t give an opinion on its sound fidelity, but so far it’s been great for listening to podcasts.

The BW-F4 charges by USB and can run from battery for most of the day.

It’s available online for about US$55.

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Review: SureFlap microchip cat flap

  • Reviewed by: Jonathan Oxer
  • Bought from: Pet Barn
  • Price at time of review: AU$198

Most cat doors are a simple flap that can be pushed open from either side, and allow any cat to pass through. The SureFlap Microchip Cat Flap is physically quite similar to a traditional cat flap, but it includes an RFID reader that allows it to scan the RFID microchip implanted in your cat and only unlock if it detects a recognised ID. All other cats (and other unwanted intruders such as squirrels and possums) are prevented from entering.

There are two models available: the basic Microchip Cat Flap featured in this review, and the more advanced DualScan Microchip Cat Flap. The difference is that the standard model only includes an RFID reader on the outside while the DualScan has separate readers on both the outside and the inside, which allows it to provide more advanced features such as allowing one cat to exit while keeping another cat locked inside.


Physical installation of the Microchip Cat Flap requires some DIY skills, depending on the material in which it’s mounted. Fitting it in a wooden door or plain wall is a simple matter of tracing the shape, cutting it out with a jigsaw or similar, sliding the flap into place, and screwing it on. If you want to mount it in a glass door you’ll probably need to use the services of a glazier to make the cut for you, or replace one of the glass panels in the door with timber.

Once the flap has been mounted, programming it to recognise your cat is incredibly simple. Just put in the batteries, press the “program” button, and either hold your cat near the entrance of the door or just wait for it to come and investigate by itself. As soon as the flap reads a valid implanted RFID chip it will store the ID and enter normal operation mode, which will cause it to unlock whenever it sees that ID. Its memory can store up to 32 IDs, and you can also erase its memory and start again if you accidentally program the neighbour’s cat in by mistake!

Setup really is ridiculously easy. There’s no app to install, no Bluetooth or WiFi configuration, nothing confusing at all. Just power it up, press that button, and you’re done. I can’t overstate how smooth and easy the setup process is.

The only reason the MicroChip Cat Flap doesn’t receive a perfect 5/5 score for setup is because of the effort involved in physically installing it. This isn’t something you can take out of the box and use: you’ll need an hour or two of messing around with tools to get it installed, but once you’re past that stage it’s totally foolproof.

Setup score: 4 out of 5


One of the reasons the SureFlap Microchip Cat Flap is so easy to set up (hooray!) is because it doesn’t have many features (boo!). Once you’ve programmed in your cat IDs, the only control you have is a manual rotary dial that lets you select one of four operating modes: bidirectional; in-only; out-only; and locked. Most of the time you can just leave it in bidirectional mode, which means it will scan RFID tags to only let recognised cats enter but let any cat exit. If you want to trap your cats inside at night you can set it to enter-only, and they’ll be able to come inside but not get out again.

There’s no way to set the mode electronically, or to set acceptable time periods for different modes. Twisting the knob is the only way to change it.

Feature score: 2 out of 5


If you don’t care about different operation modes at different times of day, there’s nothing to do once the flap is set up so there’s not really any “usability” from that point of view. However, I had some major problems with it: including one problem so bad that it lead to one of our cats having part of its tail amputated. But we’ll get to that in a moment.

The flap requires significant force to open so our cats have had trouble pushing it open. As a result they couldn’t work out whether it was in “locked” mode or if they just needed to push harder to open it.

The solenoid triggered by the RFID reader makes a significant “clunk” noise when activating which may scare timid cats. As our cats sniffed around it out of curiosity about the new thing, it clunked and made them jump. It took a while for them to learn to ignore the sudden noise each time they came near it. To get them accustomed to it we took the batteries out and taped the door permanently open for a while, so they could get used to going through it without the noise.

Changing the mode requires crouching down to twist the knob while peering at the small symbols printed on it. Because it’s mounted down near the floor, you need good eyesight to see the symbols from a distance. Just checking what mode it’s in requires bending down close to it. Being able to tell at a glance from across the room would be very handy, and could be achieved by something like a coloured dot that changes with the mode.

Now for the really bad part. I’m sure the vast majority of SureFlap customers don’t have this problem, but one of our cats suffered a serious injury trying to use the door. Because she couldn’t figure out how to get the door open to go outside, she got in the habit of bashing at the bottom of the flap with one paw. The plastic locking tab that keeps the door closed is exposed on the bottom edge, so if she was desperate and persistent she found she could get the door to pop open slightly inwards, by bouncing the door as the locking tab was pushed down by her paw. She’d then pull the flap fully open and wriggle underneath to get outside, with the door opening inwards towards her – the opposite of the direction it’s meant to go!

The exposed locking tab on the bottom of the flap
The exposed locking tab on the inside bottom of the flap

But of course the flap is spring-loaded so it pushes down and tries to close, and because her tail is the last part to go through the door it gets pinched between the frame and the flap. The result was that one time she got her tail caught badly enough that she pulled apart two of the bones in it, and afterwards the end of her tail had a right-angle bend in it. That was bad enough, but then the tail began to die. Our vet said the only thing to do was to amputate it just short of the break, so now her tail is about 1/3rd shorter than it used to be.

Usability score: 1 out of 5


The build quality seems excellent. I pulled it apart to look inside and found that it’s very well made, and the coil design (looping right around the entrance instead of being merely placed above it) gives great read range. It recognises our cats as soon as they walk near it, before they even put their head into the entrance.

Quality score: 5 out of 5


Unfortunately this is where the SureFlap Microchip Cat Flap really loses points. It’s designed to be totally self contained: it stores all IDs internally, and provides absolutely no way to connect it to anything else. As high-tech as it is, this is not an Internet-of-Things device because it has zero connectivity. No Bluetooth, no WiFi, no Zigbee, no serial port, not even a set of dumb dry-contact terminals for activity reporting or mode control. Out of the box there is no way at all to integrate it with a home automation system.

Of course I’d never be satisfied with that, so my plan is to retrofit a DIY interface of some kind to report activity.

Extensibility score: 0 out of 5


If you have a problem with feline intruders, this may well be the solution you’re looking for. But to use it as part of a larger home automation system will take some significant work and ingenuity. You also need to pay close attention to how your cats start using it, so that they push on it the right way and don’t develop the bad habit of trying to pull the door open.

Overall score: 12 out of 25, and (in our case) a large vet bill and distressed cat.