The last six month, we are trying to develop and made a personal electronic system.
This system is based on the next drawing:
As you can see the alimentation is not in the head. We chose to separate the position of the alimentation to the other board. When the alimentation will start to deliver a lot of current, some part will become hot and it could be a problem in the head. So the alimentation will be on the back.
The I/O Board and the Odroid are together in the head because this bus is really sensitive and in order to prevent the problem we decided to minimize the distance between the two connectors.
As you can see the I/O Board is the center of the drawing but it’s only because it’s the connection between the all part of the robot, but the real control is made by the Odroid which compute the different algorithm.
So, now we will develop about each personal part.
#I/O Board
##Alimentation
First of all, the I/O Board has two ways to be powered. One by the alimentation connector, which is allowed for when you use the entire robot, and a second by the programming port, but you don’t power the ODROID. This protection is here to permit the reprogrammation of the Arduino part without the consumption of the ODROID ( theoretically 2A at max which is very big for USB port).
##USB HUB
The second part is the USB Hub. It allows a simple connection with every part of the I/O Board. Moreover we have prefered to keep a real USB communication ( in opposition to USB2Serial communication) between Arduino Due Part and Hub.
The direct integration of the USB hub has suppressed the connectors and lightened the I/O Board.
##USB2AX
They are directly connected on the USB Hub. So you can use the script made by Nicolas Saugnier to reprogram the device.
But please be carefull if you reprogram the device, we have suppressed the solder point between RX and TX.
The integration of the USB2AX was from the source that you can found here.
##Arduino Due
We have chosen to integrate an Arduino Due for two reason:
- The ATSAM is the newest technology of ARM core
- The Arduino Due is the only board Arduino compatible with ARM microcontroller
In order to allows an evolution of the board, and to authorize other usage of it, we have kept some headers like on the arduino Due.
You can found the mapping here. The name of the Pin is the same to the arduino due. This property is necessary to be compatible with Arduino.
#Alimentation
The main part of the alimentation was the security. When you use the robot, you need ,if a problem appears, that the motors don’t burn. In order to save the motor we have decided to split up the logical alimentation and the power alimentation.
This choice was made to separate any problem on 14V and 5V. We will see after that we need 5V for 14V alimentation but in order to stay safe, we will add a 5V regulator.
##Logical Alimentation
For this section we have chosen to use a chip which can deliver 5V - 3A ( ODROID need 2A at maximum)
If you observe the drawing, you can observe that we have added a resistor. It appears that it’s needed to obtain 5V with our capacitor value.
You can found the datasheet here
##Motor Alimentation
The alimentation is based on a hysteris buck regulator.
More information will be available as soon as possible