First I made a testing chassis for the vibrating motors. As it is seen in the picture they are wired (connected with a thin copper cable) to a battery – this allowed me to make some experiments before deciding how to put them on the final version of the board. It turned out that they should be in angle. I decided to put them in 90 degrees.
So, I made another chassis with the 2 motors positioned in 90 degrees (2 x 40 degrees)
I used a double-sided prototyping board and the motors’ contacts fitted nicely into the holes, no soldering was necessary – I just fixed them to the board with isolated wires.
On the top of the chassis, I tied a shield-like board that connects motors to the MCU board. Later I may need to add some components on that shield board, like a driver for motors, sensors, etc.
The 2 vibrating motors, even though I bought them together, do not work the same way. That creates some difficulties controlling the direction of the bot – it turns well in one direction but not that well in the other. There are even bigger problems moving forward.
In the next version, I should definitely make changes in the vibrating motors – use some of those button-like ones and also change their angle. A friend of mine suggested that I should probably play more with the “legs” as they are crucial for the movements with which I agree.
The battery is too big, but the button cell battery is not enough to power the MCU and the motors for a long time, so I should probably think of another power source.
There is a short video on YouTube that shows more photos of how I built this with some footage at the end of the robot moving around.
Any comments and suggestions are really appreciated.
I have finally managed to finish the first version of the schematics and PCB‘s and to order the first 3 pieces. This work is based on some previous experiments and designs.
The schematics is nothing special – it is the well known minimal configuration for the ATtiny plus just few addition components – some of them optional.
The required components are the 2 capacitors between Vcc/GND and the 10K resistor on the RESET wire.
There is RESET push-button connected to the micro-controller.
The micro-controller connects to the outside world through 2 headers – H1 an H2. They are in two different sizes for number of rasons: first – to have more connections available for wires, and second – to make sure we won’t mistake H1 and H2.
Next to the headers there is 1×2 connector for external power source.
There is an optional battery for application where built-in power source is needed.
The PCB is a fork of my previous work on a simple header board.
There are 4 holes in the corners in case the board should be fixed to another object.
On each side of the IC there are 2-row headers – on 2×4 and the other 2×5.
External power source connector is put along with the H2 header.
The ISP connector is at the top of the board. Between it and the rest of the board there is 1×6 header-like probe – this could be used for testing as well as for easier cutting off the ISP part of the board in case is not (or no longer) needed.
The pads for the optional battery are on the bottom.
Briefly, the Tinusaur is a minimal micro-controller hardware configuration based on Atmel AVR ATtiny family of products and more specifically those with DIP-8 case such as ATtiny25/ATtiny45/ATtiny85, ATtiny13 as well as their variations.
The goal of the Tinusaur project is to have a simple, cheap and accessible quick-start platform for everyone interested in learning and creating things.