Clocky is an alarm clock with a difference. When Clocky's alarm goes off, if you don't make Clocky happy, Clocky gets angry and runs away screaming. To shut Clocky up, you have to hunt it down and silence it.
After looking at Clocky I thought that it would probably be fairly simple to use Clocky's frame and parts for a small robot.
This Instructable is about finding if Clocky is any good for this purpose.
To disassemble Clocky you must first remove the battery hatch and batteries, easy enough.
When I looked at Clocky's screws I realised they are triangular socket security screws and are set too deep for a modular bit from my screwdriver set. I then used an old trick where you take a flathead screwdriver and wedge it between two of the corners of the triangle socket of the screw. This worked a treat however as soon as I cracked open Clocky, its wheels fell off. This wasn't an issue, just how Clocky is designed.
I set the wheels aside and had a look at Clocky's guts.
This is a motor unit, self-contained with a gearbox.
This is the battery container. It removes intact and can be left in Clocky or used for another project later on.
This is Clocky's speaker and weight to help Clocky stay upright.
This is Clocky's top button assembly. It looks to be removable with two small Phillips-head screws holding it in.
This is the main PCB. It is exactly how I hoped it would be. The row of eight transistors appear to be the main drive transistors that run the motors. It looks to be a full H-bridge but I will check that out a little later.
Step 9: A Little Theory
After dissecting a bunch of toys and gadgets I learned that many of them are controlled the same way, with similar electronic layouts. Usually when I see a PCB laid out like this it means I can, by trial and error, ascertain which transistors do what and then control it with one of my favourite devices, an Arduino! The Arduino is an excellent diagnostic tool for devices like this as it can give a logic signal out in a controlled manner. For example, I load the Fade sketch, connect the ground to the negative battery terminal, put some batteries in the device and power up the Arduino. By taking the lead from the Arduino's output, usually D9 for Fade, and putting it on the right point in the circuit, I can check which transistors control which motor and which direction. Take Note! Never put the output directly onto the transistor. All of the devices I have seen so far have a resistor before the transistor to reduce the power to a level where it won't kill the transistor.
I have used this technique for aTyco N-Sect, several small remote control helicopters, a remote control drinks cooler and a line-following robot from Jaycar, which I recommend highly as a good, cheap, tracked robot base.
These are the resistors I am referring to, just next to the small transistors, near the bigger transistors. Trace the circuit to check you are using the right end of the resistor or it will be bypassed and you may kill the transistor anyway!
Doing so I discovered that this point is for one direction on one motor,
and this is the other direction for the same motor.
With a little more poking I found that the circuits appear to be the same on both sides, this being one point for the other motor, M1
and this being the other point for the same motor.
This means that I can use Clocky as a base for a robot by simply tapping into these points and programming the Arduino to drive Clocky with a differential drive system. My Arduino also seemed happy to run from Clocky's battery pack, using the VIN pin and ground, making it possible for a self-contained robot with minimal modification to Clocky, leaving the opportunity to revert it back to just a clock later if necessary..
I hope this Instructable has inspired you to open up a Clocky and experiment or another device of your own and tinker.