I have a telescope with a Dobsonian mount and need to create a simple digital setting circle to make it easy to work out where the telescope was pointing. The Arduino micro controller was the perfect choice to get something running quickly:
Sensors
ADXL345 3-Axis Digital Accelerometer is used to measure the angle.
HMC5843 3-Axis Digital Compass IC provides the azimuthal angle of the object.
These use I2C interface to connect to the Arduino, my next version is likely to have a display module to display the results.
Software
I develop my projects for multiple platforms so the Qt user interface for this works on PC and Linux and soon I will have an interface running on Android. For now the application is used to enter the co-ordinates of known starts and display the resulting measurements and is connected to the Arduino board with a USB cable.
The Arduino software is where all the calculations are performed. Using some simple maths to work from calibration points, at known positions, to derive the horizontal co-ordinates for an unknown position. The Arduino code keeps track of Siderial Time so the known co-ordinates can be entered from the star chart and when the calibration is performed position is calculated.
The Arduino software is where all the calculations are performed. Using some simple maths to work from calibration points, at known positions, to derive the horizontal co-ordinates for an unknown position. The Arduino code keeps track of Siderial Time so the known co-ordinates can be entered from the star chart and when the calibration is performed position is calculated.
Contact
If you are interested then please contact me and I can share more.
Great work, i want to build one of my own, would one of these work: https://www.sparkfun.com/products/10888
ReplyDeleteHow is the accuracy? any interference from metal etc?
That sensor seems to have all you need in one module. I am investigating how to improve the sensitivity. Not as good as I would like and not nearly good enough to take measurements from. One possibility is that I have a lot of wires, or that I was relying on the USB power, but its more likely that the Arduino is electrically noisy so I am investigating lowering the power to take measurements. I have not ruled out interference from metal but the measurements are not stable even if the telescope is not moved so the main problem is not metal. Here is a good library http://www.rocketscream.com/blog/2011/07/04/lightweight-low-power-arduino-library/
DeleteAnother and perhaps more promising solution would be to use the optics from two optical mouse to track movement of the telescope. That might be a better solution in the long run. At the moment I am finding it difficult to source the mouse components and might end up trying to salvage parts.
Greetings Mr Peter
DeleteI am chandran writing to you from Chennai,India .I am in the process of building a eq mount and would like to do a goto type mount . I have no knowledge of electronics but will to learn . I was planning a gps based guide systems would you be able to share you views
regards
chandran