{"id":1035,"date":"2012-10-10T23:32:46","date_gmt":"2012-10-10T12:32:46","guid":{"rendered":"http:\/\/www.madox.net\/blog\/?p=1035"},"modified":"2013-02-24T08:52:23","modified_gmt":"2013-02-23T21:52:23","slug":"tl-wr703n-example-project-2-cute-exterminator-remote-control-toy","status":"publish","type":"post","link":"http:\/\/www.madox.net\/blog\/2012\/10\/10\/tl-wr703n-example-project-2-cute-exterminator-remote-control-toy\/","title":{"rendered":"TL-WR703N Example Project 2 : Cute Exterminator (Remote Control Toy)"},"content":{"rendered":"

The Cute Exterminator is another demonstration project\u00a0using the\u00a0TP-Link TL-WR703N<\/a>\u00a0router to create a WiFi enabled remote control toy. \u00a0It shows how the router can be used to control servos with minimal programming other than with html\/javascript and a single line of shell script.<\/p>\n

<\/object><\/p>\n

Again (well I repeat this a lot), not a comprehensive write up because it was a quick a dirty build but read on for the short description and a visual walk-through.<\/p>\n

<\/p>\n

Concept<\/h2>\n

Robots & Dinosaurs<\/a> (the Sydney Hackerspace) is co-located with the Sydney Robot Workshop<\/a>, or to cut to the point, there are A LOT of Daleks there! \u00a0I loved Doctor Who as a kid but building a large life size replica of a Dalek seemed a bit too hard for lazy me. \u00a0eBay fluffy Dalek to the rescue!<\/p>\n

\"Fluffy<\/a>
Fluffy Dr Who Dalek! In Red!<\/figcaption><\/figure>\n

It is a decent size and only costs around $25 including shipping, should fit a router! \u00a0Cute little bugger, there’s even a BONUS! \u00a0Recorded voice module! \u00a0Win!<\/p>\n

The hacking<\/h2>\n

Ripping apart a plush Dalek isn’t as emotionally challenging as tearing apart a teddy bear. \u00a0Using some sewing tools to remove the thread is handy so you don’t have to incise into the toy. \u00a0I pulled out the battery holder so I knew where the wires were, just in case.<\/p>\n

\"Batteries<\/a>
Batteries exposed, don’t ask why I have sewing tools!<\/figcaption><\/figure>\n

Digging into the fluffy Dalek reveals the inner workings. \u00a0It is basically comprised of a battery module, a switch for activating the voice and a voice module that integrates the speaker wrapped in the blue cover pictured below. \u00a0Of course there is a lot of stuffing as well!<\/p>\n

\"The<\/a>
The guts exposed!<\/figcaption><\/figure>\n

Since we’re hacking though, we need to go deeper (no Inception jokes thanks) and see how the voice module ticks. \u00a0Luckily it is very easy to pry apart with a small flat screwdriver and inside shows a small speaker wired up to a PCB. \u00a0Surprisingly for something that is off a mass produced toy, the PCB is extremely well labelled.<\/p>\n

\"The<\/a>
The electronic guts<\/figcaption><\/figure>\n

Now that we can see all the apparently simple innards, we need to figure out how it ticks. \u00a0A common mistake that many people make when they take things apart to learn how they work is that… well they take it apart. \u00a0The easiest way to understand how something works is to keep it in working order and observe it working. \u00a0In the case of the Dalek, I kept all wiring in place and and measured across various points as I squeezed the Dalek to make it squeal.<\/p>\n

The two wires coming in from the battery were obvious starting points and measured 4.75V. \u00a0Great, this will go well with the USB 5V power of the router.<\/p>\n

The ‘switch’ that activates the voice module should be a simple normally open contact based on assumption. \u00a0What assumption? \u00a0It is probably safe to assume that whatever you buy that is made in China is made as cheap as possible. \u00a0Which leads to the next question what does the switch do? \u00a0The switch comes in via two white wires and with a multimeter we can simply measure each wire with reference to the ground or black wire from the battery. \u00a0We take a set of measurements with the switch in its normal state, as well as when it is ‘squeezed’. \u00a0What do we find? \u00a0We find that the switch pulls low a 4.75 voltage to active the voice module.<\/p>\n

i.e. to activate the voice module, we need to pull the “TG” pin near the VCC\/+ve (red wire) low. \u00a0One of the simplest ways to effect this voice module is to use an open collector output.<\/p>\n

\"A<\/a>
A better look at the PCB<\/figcaption><\/figure>\n

The electronics<\/h2>\n

Now that the Dalek has been hacked open and its inner workings deciphered, we can try figure out what components we need to make it a remote control toy.<\/p>\n

So the electronics include :-<\/p>\n