Read in English     Türkçe Okuyun

I'm tired of my two sons' begging to have a family dog.

It's not that I don't like the idea, it's because we move frequently and some times our home could be an apartment flat which cannot accomodate a pet. And moreover, I know the responsibility will eventually put on my shoulders.

And, a new idea came to my mind. Why don't we make our own pet?

I mean not in the flesh, but rather a pet robot.

So, I've ordered a few parts.

My robot will look like Stingray but not exatly the same. I am going to use Stingray motors and main wheels. I will make the chassis from black HDPE which is 4 mm thick. The HDPE is a God-send product for hobbyiests. Easy to work with and durable. And, the brain is going to be based on Arduino. In addition to regular ultrasonic sensors, I also plan to use a new cam module which is still alive at this time on Kickstarter. I will put it on a pan tilt servo unit to enable it watch every direction. In a few sentence they describe it as "Pixy is a fast vision sensor you can quickly “teach” to find objects, and it connects directly to Arduino and other controllers."

My initial goals are to have it play in the house, e.g. when I throw a ball I expect him to follow, find and fetch it.

I will post my work as I make progress, because I learned a lot from the online community.

İki oğlumun "baba n'olur bir köpek alalım" isteklerinden bıktım usandım.

Köpek sevmediğimden değil, sık sık taşınıyoruz ve her zaman bahçeli bir evimiz olmayabiliyor. Bazen bir apartman dairesinde yaşamamız gerekebilir. Ve daha da önemlisi, köpeğin bakım sorumluluğu eninde sonunda benim omuzlarıma yüklenecek biliyorum.

Birden aklıma bir fikir geldi. Neden kendi köpeğimizi kendimiz yapmıyoruz ki?

Tamam etli, canlı bir köpek değil ama robot bir köpek.

Ve, oturdum bir kaç parça siparişi verdim.

Robotumuz, Parallax firmasının Stingray'ine benzer olacak. Stingray'in motor ve tekerleklerini kullanacağım. Robot şasesini siyah 4 mm kalınlığındaki HDPE'den yapacağım. HDPE hobiciler için bulunmaz bir nimet. Çalışmak için kolay ve aynı zamanda da dayanıklı. Ve, robotun beynini Arduino oluşturacak. Ultrasonic sensörlere ilave olarak Kickstarter'da halen canlı bir kampanya ürünü olan bir kamera takmayı planlıyorum. Kamerayı pan ve tilt yapabilen bir servoya yerleştirerek her yöne bakmasını sağlayacağım. Kickstarter'da Pixy için kolayca eğitilebilen bir görüntü sensörü olduğu ve Arduino'ya kolayca bağlanabildiği yazıyor.

Robot köpeğimiz için temel hedeflerim, evin içinde oynayabilmesi, örneğin; bir topu attığım zaman onu takip ederek, bulması ve geri getirmesi, vb.

Zaman içinde yaptıklarımı burada sizlerle paylaşacağım çünkü ben İnternet üzerinde yaptıklarını paylaşan insanlardan çok şeyler öğrendim.

I'm working on the software side. Nothing special to show.
Trying to figure out if there is any slippage and rotational differences between the right and the left wheels.
Still want to see some uninteresting moves? Here is the video.

The battery (currently a Lion 3 cell battery) is temporarily attached to the tail, it will go inside the body in the end. Now it comes handy to access it easily to charge or unplug.

To power Raspberri Pi, I'm using a buck (DC to DC) converter, it's just a few dollars worth but produces pretty stable output voltage. I've tried it with my adhustable power supply between 11-15v and it stays 5 volt without fluctuating. I think it uses LM 2596. The datasheet says it can output 2A steady current which is enough for me since I don't use RPi to power anything yet.

One important thing to express again is that there are three different voltages going around the robot; 12 volt, 5 volt and 3.3 volt. If you are not careful you can easily burn things out or damage badly.

Well, OK.
It's been some time, but I'm back.
During this time I decided to make some changes / improvements to my robot.

First, I've moved from Arduino to Raspberry Pi 3. It's much more powerful with Quad Core 1.2GHz 64bit CPU, and comes with Wifi and Bluetooth, runs Linux, has direct HDMI outputs.

Second, I upgraded my motors with the ones come with encoder units. And also, the motors produce 320 rpm. With my wheels (6 cm radius) the robot can travel as much as 201 cm/sec which is more appropriate in my opinion. As you can see in the below pictures I put a supporting aliminum u profile under the top body panel to eliminate sagging of the body due to the weight.

Third, I bought Pololu Dual MC33926 Motor Driver Carrier that has a wide operating range of 5 – 28 V and can deliver almost 3 A continuously (5 A peak) to each of its two motor channels. I thought that Parallax HB-25 H bridges were overkill with 25 A and took much more space comparing this new tiny pcb.

And lastly, I've changed my IR sensors from analog to digital. They are from Sharp and 5 cm sensitive.
Curious of the black plastic thing above the sensors?
It's plastic tie lock bumper to absorbe any crash force and to keep sensors safe ;)