This has been a long time in the making, and we have finally got to the stage where we can add the chicken to the mechanism and electronics. The design is a chicken (made from papiermache) sitting inside a hand basket, and Rumena wanted it to cluck and flap its wings like a chicken. That meant we had to find a way of attaching wings and then making them flap at the same time as generating the clucking sound. Here is Rumena’s original concept at the centre front. It is the yellow and red one between the bucket and the boot and the head is pointing towards the left:
The sound player is straightforward and is an Adafruit WaveShield attached to an Arduino Uno. Most of the objects we have creeated have this setup, as it is easy to work with and inexpensive. Also, I personally like the WaveShields as they have a simple design and so easy to understand. I have build around 40 of them.
The original mechanism for flapping the wings was based around a crank that was attached to two conrods, and which operated two levers attached to the basket. But this was too bulky and would not fit under the chicken. So, instead, we opted for a high speed servo. The servo pulls and pushes on levers attached to dowls which are themselves attached to the basket, but can rotate. It’s probably easier to just show the image below:
The wings are then attached to the dowels and can flap backwards and forwards, but only by around 60 degrees of rotation at most. the servo is controlled using a Polulo Micro Maestro, as this makes it easy to control via simple serial commands sent to it by the Arduino Uno:
The whole flapping/clucking is triggered using a sonar attached to the Uno. Moving within 1m of the chicken will trigger it. In the image below the sonar is hooked up to the Arduino Uno, and the Arduino is connected to the servo controller (not shown). The sonar is a very inexpensive off-the-shelf HC-SR04, which has a range of about 3m.
The next image shows the whole setup with the servo and controller too. Note the simple mechanism to operate the levers on the basket.
As with most of the other objects we have created, the audio uses a 3.5W kemo amplifier, and a 5W Visaton speaker The whole thing is shown in the image below:
At the top centre of the previous image there is a voltage regulator. This is a replacement to the original, which was faulty and consequently I managed to fry two servos before sussing out that the voltage regulator was kaputt. In fact, one of them actually went up in smoke as I was on a Skype call with Kate!
The Chicken was a bit floppy as it is made from papier mache, so Kate stuffed it to make it a bit more robust and so that the head would stay in place:
The wings were attached to the two shafts that protruded from the top of the basket, and which are directly connected to the servo which makes them flap. We covered the mechanism with the lining form the basket, and attached the sonar (distance sensor) to the front of the basket so that the chicken would start flapping and clucking when someone stands in front of it:
Finally, the chicken was fitted into the basket! The egg at the side of the basket contains the giant battery that powers it.
Here’s a video of the chicken when we tested it out: