EEVblog Electronics Community Forum
Electronics => Projects, Designs, and Technical Stuff => Topic started by: PioB on September 02, 2013, 07:57:59 pm
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Hi,
I am not sure if that should go here or in the microcontroller section..
My father-in-law is a member of an Astronomical Society. Some time back they got a donation of an 8 ft parabolic dish.
Due to my background in computational chemistry, a ham radio exam ~20 years back, and more recently an interest in arduino/microcontrollers he asked me if I could help him with the design of the antenna controller, a challenge I happily accepted.
In a first stage that should only be able to control the elevation, with a possible extension to azimuth later. So my general idea was as follows:
(https://lh3.googleusercontent.com/-jSKursaIWOU/UXBQtKSOlgI/AAAAAAAACNU/lgO3nnOBe_U/s720/Slide1.png)
An Atmega328P is connected to the computer via an usb (FTDI FT231X) chip, a few buttons/rotary encoder for the menu control, a PCF8574 Port expander for the LCD, an eeprom for data/elevation storage and a P82B715 I2c bus extender.
On the other end of this is a board with an accelerometer (Invensense MPU6050 on a GY-521 board from amazon) which will serve as an inclinometer by using gravity as a reference.
An optocoupler will drive a Pololu Motor controller http://www.pololu.com/catalog/product/759 (http://www.pololu.com/catalog/product/759) (up to 40 V 20 A)
The actuator is not bought yet, but will probably be of the 12 or 24 V variety.
I would be very happy if someone could review my schematic which is here:
https://lh6.googleusercontent.com/-VPeZ0D-Z9CA/UiTkMUqQV9I/AAAAAAAAHcM/Q2QxvyUBtsw/s2560/Schematic.png (https://lh6.googleusercontent.com/-VPeZ0D-Z9CA/UiTkMUqQV9I/AAAAAAAAHcM/Q2QxvyUBtsw/s2560/Schematic.png)
The (eagle) design files are on github https://github.com/baettigp/Dish-Controller (https://github.com/baettigp/Dish-Controller)
Mainboard
The reset circuit leaves the possibility to switch between a capacitor in series and one in parallel, as Arduino seems to use the series version in their boards...
The accelerometer-adapter board is already made and the accelerometer sends back results if connected via a second P82b715.
(https://lh6.googleusercontent.com/-WuGz-CdGkJM/UiTsmucHrNI/AAAAAAAAHcg/sy1n30fCIeA/s640/20130902_215212.jpg)
I have learned very much during the design of this project, but not being an EE, I hope I haven't commited any really big blunders.
Thank you very much for looking at my design.