Yes

I think the Arduino is an excellent choice since the firmware can be up graded so easily by anyone using a USB cable. I guess it would be good if we could outline the structure of it and possibly create libraries/modules for the different sections like: communication, motor control, camera interface. This way it could be used to control more than just the Merlin/Orion by changing the libraries used in a build.

I think the following libraries would be useful:
Communication - bluetooth, wifi, etc.
Motor control - stepper, servo, dc motor
Camera - shutter, focus, exposure monitor
System monitoring - error detection
Main control - communicates with all the modules/libraries
Interface  - joystick, lcd

We will also have to establish a variable naming protocol so that all the modules will understand each other and there aren't conflicts. This will require some project management in order to keep everything working. I would suggest a Wiki page setup so that information from the developers can be added and edited as needed. This also stops the need to search posting here to find out the information you require.

Does the Merlin/Orion head use a dc motor with an encoder?

If so I am working on a motor control that will run a 12v motor with an encoder, my prototype boards should be in next week so I can start testing. These boards require either a step and direction input or a serial command. I am setting up with the serial command structure for myself. With the Arduino this means either using a Mega board with it's multiple serial ports or using software ports. I am leaning towards the Mega board myself at this time and will build a shield that will interface with the camera, dc servos, and the bluetooth.

fma38 wrote:

Before starting the wiki page, we should discuss here what we really want to implement. My first goal is to make a simple controller, which just replace the existing one. We can maybe add a few simple things (like another contact for focus or joystick input for manual move), but I didn't plan to add complex things like lcd, wifi or so.

This controller will need a daughter board, to put the encoders amplifiers/counters, and motors amplifiers; to control another kind of head, it will be possible to make another daughter board, instead of mixing all technologies.

The com. interface should be serial, as it is the most universal one (which can be connected to a PC, or to any XXX-to-RS232 converter, including wifi, bluetooth, zigbee...

My 2 cents...

I agree with the daughter board scenario I just want to make sure all the components are compatible. I was just thinking separate libraries/modules in the Arduino code would be best. It's like building your code with Lego blocks allowing customization within some limits.

If the pic is locked nobody can backup the code from it. Some newest pic's has military grade code protection. Others has standard grade protection (like the pic in Merlin), but it is also very strong and safe.

Locked Pic accepts only one command: full erase. It erases the whole content of the flash and the lock bit.
After erased, they easily can be re-programmed.
This in-circuit reprogramming works well. Just 5 pins needed: gnd, vcc, vpp(programming voltage), pgClock, pgData.

Tamas

my 2 cents

I would prefer not to bind this idea to the Merlin-hardware as the Merlin is not flexible enough to handle the some of the widely used cam-lens-combos

using an arduino to control a basic panohead could be a great openhardware / opensource project

somekind like the reprap-3d-printer-project

I wonder if the encoder could be changed for one that is TTL compatible. I won't be doing this myself since I am making my own mount. The software/firmware is still of interest to me so that I can keep my stuff compatible.

UrsaMinor wrote:

The existing electronics in Merlins can be re-used.
It has a L293 driver, two nice PIC microcontrollers etc...

Just write a new firmware and reprogram the PICs.
They can be reprogrammed as soldered into the circuit.

Tamas, do you think it is possible to buy the original internal controller alone? Your idea is nice, but I don't want to overwrite the original firmware without possibility to go back. So, If we could buy a complete controller to develop an alternate firmware, that could be nice.

This way, it could be possible to sell this controller with the new firmware pre-loaded, and we may even find a way to allow users to update the firmware without using a special PIC programming tool (I don't know much PIC, but it may be possible to write some sort of bootloader?).

Herre is a first draft of the arduino shield I'm thinking about for the controller replacement. Feel free to comment.

Looks good. Would you be able to add a flash monitor input, this allows the controller to ensure the exposure is completed prior to next step.

I will check into it, but from what I know is it will switch a low voltage this is why some older flashes can't be used since their voltage is too high. We could use an analog input since it looks like the pins are all used. I am sure Vcc will work and then monitor for 5v or 0 and that will indicate the flash/shutter state.

Thanks. I will add an opto-coupler so it will be safe. And I don't think we have to use an AD input, as all pins are simple IO by default.