Tag Archive | "hacked"

Breaking up an automatic room deodoriser – part one

In this article we attempt to break down an automatic room deodoriser and have some fun.

Updated 18/03/2013

[Update – we won round two]

Today we are going to tear down an automatic room deodoriser. Why? Why not! After walking around the supermarket as one does, pontificating over the need for doughnuts – I noticed this package on sale for eight dollars:

unopenedss

What grabbed my attention was the words “movement sensor” and the price tag. A sensor by itself can cost more. Where’s the catch? I am sure the company makes their money back from selling the refills, in a similar method to ink cartridges and razor blades. Good for them. However, perhaps this can be good for us! So into the basket and home it came. My flatmates thought it was a lovely gesture to have one in the hallway. Hah! As Dave Jones would say, “don’t turn it on – take it apart!” So let’s go…

The can of spray went straight into the WC, nothing of interest there. Three alkaline AA cells were included:

alkalinesss

Well that’s a good start, you can always use these in a camera or something else. Armed with a philips-head screwdriver and a pair of needle-nosed pliers, the entire assembly came apart very easily and without force. I must congratulate the designers, you almost get the feeling that this is designed to be repaired if broken, and not replaced. The process of disassembly was quite easy:

1ss1

The front cover came off quite easily. The switch on the right enables/disables the movement sensor; the LED indicates the repeat mode for the spray; and the black switch controls the duration between sprays – off, 9, 18 or 36 minutes.

2ss1

After removing the rear panel with four screws, we can see the motor and one of the two PCBs. Two more screws, and we can remove the electronics and mechanical sections:

3ss2

This is the front-facing part of the motor board. The motor turns one direction then another to have the plastic ‘finger’ push down and release on the aerosol can nozzle. The gear ratios are quite large, allowing the motor to exert quite an amount of torque. The metal base board has some convenient mounting holes as well, so this could be reused easily. If you had a pair of these you could drive something that is quite heavy at a sedate speed.

4ss

Here is the main controller board, with nicely colour-coded JST connectors for leads to the motor, power source (those 3 x AA cells, 4.5V) and to the switch that turns the sensor on and off. The underside is very professional, all SMD:

6ss

The motion detector’s board plugs nicely into the main board, thanks to the 2×9 pin header and socket arrangement:

5ss

Now it is time to see how things work. The first step will be the motor – how much voltage and current does it use? I ran the motor without a load for thirty minutes at 4.5 volts DC – the  motor body did not warm up at all, a good sign that this voltage was suitable. With regards to current, there are two measurements to take – current while free-running, and under maximum load (i.e. feeding the motor 4.5 volts while holding the gears still). While free running, the current drawn was 34 milliamps:

freerunss

… and when I held down the gears so the motor could not turn, the current drawn was 305 milliamps:

maxloadss

So now we have a nice strong motor that can run at 4.5 DC, and draws between 34 and 305 milliamps. That’s a good start. Furthermore, being able to stick the meter display to the desk lamp really makes life easy. Now it is time to investigate the detector. It had a few codes on the PCBs, such as KT-7964, Smart Motion A-06 and RB-S04 which I searched for on the Internet without any luck.

So the next thought was to feed it 4.5 volts DC, and use the Scanalogic2 to analyse any signals or voltages around the PIR sensor module to see what happens. However, the entire system was dead, it would not do a thing. The same problem occurred at four volts DC. No luck either. After the initial power up, the unit should light the LED for one second, then activate the motor for a “first spray” – but nothing. Hmmm.

So at this point we are at a brick wall, however this is not the end. Research will continue to look for details of the PIR unit, and once it is working independently a new post will be published.

This article also shows to me and others that not everything is a success first time. It can be disappointing, however it’s not the end of the world. With every failure comes knowledge which can be used the next time around. So subscribe to the web page updates, and keep an eye out in the future. High resolution images are available from flickr.

In the meanwhile have fun and keep checking into tronixstuff.com. Why not follow things on twitterGoogle+, subscribe  for email updates or RSS using the links on the right-hand column? And join our friendly Google Group – dedicated to the projects and related items on this website. Sign up – it’s free, helpful to each other –  and we can all learn something.

Posted in hardware hacking, room deoderiser, tutorialComments (10)

Kit Review – Alan Parekh’s Infra-Red Jammer

[Updated 17/01/2013]

In this review we examine another kit which goes hand in hand with other mischievous items such as the TV-B-Gone – the Infra-Red Jammer kit by Alan Parekh of hackedgadgets.com. The function of this product is to create infra-red signals that are stronger than those from a normal remote control, thereby rendering it useless. Our jammer sends the signal out using four high-output infra-red LEDs, on the following frequencies: 30, 33, 36, 38, 40 and 56 kHz.

This is controlled by a small MCU that is included in preprogrammed form with the kit, so you don’t need to do it yourself. However, if you are building a jammer from scratch, Alan does allow the download of the hex file to program your own. However, please note that this kit is not an open-source hardware, so you cannot just start knocking out your own. But enough talking, let’s get building!

The kit is packaged in the typical minimalist fashion, the parts inside an anti-static bag:

bagss

Upon turfing out the contents, we find them to be:

contentsss

Unlike most other kit suppliers, I was very happy to see the IC socket included. It probably cost about 10 cents, but it can save someone a whole day of mucking about if they aren’t the best at soldering, and don’t have an electronics store nearby. Furthermore the PCB is solder-masked and silk screened nicely, and is of a decent thickness. Once again – if smaller companies can offer kits with such great PCBs, why cannot larger multi-million dollar outfits like Jaycar offer such great PCBs in their kits? Grrr. Anyway.

The assembly instructions have been compiled into a very neat and tidy book that is downloadable as a .pdf file. It is very clear and easy to follow, great for beginners or enthusiasts alike. So at this point it’s time to get soldering.

At first you need to decide upon the power output strength which is determined by R1 and R2 – for me, it’s all or nothing so I went for the high-power resistors. Thankfully values to use three output levels are included, so you will have some spare resistors at the end. Once those are in, the rest of the assembly is relatively straight forward:

pcbss

What did take me be surprise is the length of the leads on the two electrolytic capacitors – they were very short. This made mounting them difficult:

shortcapsss

However with a little perseverance they went in and stayed put. Although the jammer is activated for thirty seconds by pressing the button as seen in the photo above, there are also two pads on the PCB for another button… so you could, for example, mount the jammer under a lounge or inside an object, and have the button wired remotely. Very good idea:

extraswitchss

They are visible between the diode and the press button. Finally it was time to plug in a 9V battery and start jamming. Interestingly enough the PCB size matches the profile of a typical PP3 9V battery, so if you insulated the PCB with tape or another material, you could mount the PCB onto the battery:

9vsamess

As decided earlier, I chose the highest power output setting by using the low values for R1 and R2. At this point I was curious as to how much current the jammer will draw while operating – which turned out to be 209 mA:

209mass

So bear this in mind if you are going to spend the day jamming up things. You might want to carry a spare battery, or wire a couple up in parallel. But now it was time to get jamming and have some fun. The check of the infra-red LEDs was successful:

operatingss

A test at home showed it knocked out all the IR receivers on my sound and video gear from a distance of around 5 metres. I couldn’t try any further as a wall was in the way, but with the unit set to high power I’m sure it should be good for around fifteen metres at least.

Now when you press the button, the jamming will run for thirty seconds. However you can increase this by buffering up more presses – for example if you press the button three times the jammer will run for ninety seconds. If you were in a trade show, or somewhere you needed to create some mayhem, build a TV-B-Gone and one of these jammers. Turn off the screen then setup your jammer for a couple of minutes. You will drive the presenters positively nuts. Awesome!

Conclusion

This is another fun and inexpensive kit that can be used for hours on end in various situations. It was easy to solder apart from a couple of capacitors, and getting them in wasn’t really a problem once you held them in with some blu-tac. So if you’re looking for a gift for some trouble-makers, or just want to stop people changing the channel during the cricket, this kit is for you. It is available directly from Alan’s website here: http://alan-parekh.com/kits/ and is a steal for less than US$20 delivered.

In the meanwhile have fun and keep checking into tronixstuff.com. Why not follow things on twitterGoogle+, subscribe  for email updates or RSS using the links on the right-hand column? And join our friendly Google Group – dedicated to the projects and related items on this website. Sign up – it’s free, helpful to each other –  and we can all learn something.
[Note – this kit was a promotional consideration made available by Alan Parekh]

Posted in infrared, jammer, kit review, product reviewComments (0)


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