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Author Topic: AstroEQ Basic Hand Controllers  (Read 7328 times)

TCWORLD

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AstroEQ Basic Hand Controllers
« on: April 10, 2017, 01:13:55 »

Hi,

So many of you by now have seen me mentioning hand controllers for the AstroEQ. Supported with the release of the V8.0 Beta firmware, and using the hardware added in the V4.6 AstroEQs, I am in the process of developing two different hand controllers to allow the AstroEQ to be used without a PC connection.

The first of these, and the only one currently developed, is the Basic hand controller. The idea behind this design is to allow very simply control over the AstroEQ when you don't need the full go-to capabilities. This will allow you to drive the mount in a completely standalone fashion with no PC connection needed at all. It consists of four push buttons for NESW, and a fifth button to select between one of three different speeds (ST-4 speed, 2x speed, and GoTo speed).

I have just finished building the first prototype, a photo of which is below. I am making use of a 5-button key fob style case as they are very cheap (2 each) and already have five nice conductive rubber push buttons. To facilitate the three speed selections, inside the fob there is actually a small 6-pin microcontroller (ATTiny10) which is powered entirely from the pull-up resistors on the ST-4 lines meaning that no external power supply is needed.



The MCU (the software for which is with a whopping 82 bytes!) is required to allow the fifth push button to select between three different speed states by driving the control pin in a specific way - shorting to GND is one speed, connecting to GND via a 2k resistor is a second, and floating the control line a third. A low voltage LED in series with the control line allows for an indication of speed based on how bright the LED is.



It is also possible to build your own version, however I would not recommend the fob case as the circuitry requires quite a few very tiny SMD parts.

Instead I would recommend using simple tactile switches and a slide switch for speed. Below is a schematic of the simpler version of the hand controller. The only parts required are 4x tactile switches (push buttons) of your choice, 4x 10nF capacitors for debouncing, 1x 3.9kOhm resistor, and 1x SP3T slide switch (or similar).



The speed selection switch selects (from left to right in the diagram): ST-4 speed, 2x speed, and Go-To speed.



In terms of functionality, the four push buttons are used to select the direction (you can press an RA and DEC button at the same time) and the slide switch selects the speed. When the switch selects ST-4 speed or 2x speed, the mount will also be set to do Sidereal Tracking. When you select the Go-To speed, the mount will not perform any sidereal tracking.

The speed modes were chosen so that if you unplug the hand controller, the mount will stop moving because the speed pin will float.

Additionally, when doing Sidereal Tracking, the speeds are relative to the sidereal rate. For example at 2x speed, the mount will move 2x speed in DEC+ and DEC- directions, 1x speed in the RA- direction, and 3x speed in the RA+ direction. In other words, the speeds are the rate at which the stars move, not the mount.

When the hand controller is first plugged in, you must select ST-4 speed in order for it to be detected - selecting any other speed will not force the AstroEQ into standalone mode.

The basic hand controller requires the V8.0 beta firmware, and also an AstroEQ with a V4.6 hardware revision. If you have a V4.5 or V4.4 mount, it will be possible to add support however it will require a simple hardware modification. I will write up details on the required hardware modification in a tutorial.



I will publish a tutorial at a later date on the basic hand controller design and operation. In the mean time, if you need any clarification, please post in this thread.

I hope this will be a welcome addition to the AstroEQ controller - I know a few of you have been missing this most basic of functionality.


Kind Regards,
Tom.
« Last Edit: April 10, 2017, 01:17:17 by TCWORLD »
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Tom Carpenter (AstroEQ)

adfuller

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Re: AstroEQ Basic Hand Controllers
« Reply #1 on: April 20, 2017, 12:48:12 »

Hi Tom,
This looks to be a great addition.  I've started building my own DIY controller as per your design (nothing fancy)
As I have a v4.4 it would be good to know what else I need to modify to the hardware.
Cheers
Andy
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TCWORLD

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Re: AstroEQ Basic Hand Controllers
« Reply #2 on: April 20, 2017, 14:17:21 »

Hi Andy,

I'll add some further details tonight about upgrading the older hardware.

If you don't already, you'll need to put in an ST4 socket - I believe the V4.4 has the footprint on the PCB (part number is in the BOM for the latest AstroEQ). There are two connectors J1 and J2 which need to be connected together pin1 to pin1, pin4 to pin4. You will also need to make another connection and add a 1k resistor, I'll add details of that tonight.

Kind Regards,
Tom.
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Tom Carpenter (AstroEQ)

TCWORLD

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Re: AstroEQ Basic Hand Controllers
« Reply #3 on: April 20, 2017, 20:42:11 »

As well as the ST4 port, you will also need to make the following connections:

  • A 1kOhm resistor connected between PD2 (pin 12) and PE0 (pin 31) of the ATMega162
  • A wire jointing PD2 (pin 12) of the ATMega and pin 1 of the ST-4 port (it's the only pin of the ST-4 with no connections on the PCB)
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Tom Carpenter (AstroEQ)

paul_astrix

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Re: AstroEQ Basic Hand Controllers
« Reply #4 on: April 29, 2017, 16:38:34 »

Tom,
When I was building using your most recent 4.6-PTH board and studying the schematic I guessed you had this planned.

It's a nice simple solution, assuming DIY builders used a 10ppm crystal, like the Farnell type you specified.

The great bonus is the ability to unit test the power supply, cabling, steppers and mount mechanics. Once users have proved a simple hand controller test, only then can we move onto complex software problems like "X doesn't work with Y using the recent version of Z" ha ha.

Can I also suggest some special key combinations like test mode (5 revs in each direction) and a soft reset.
If you need a crash test dummy PM me.

Cheers
Paul
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janne

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Re: AstroEQ Basic Hand Controllers
« Reply #5 on: June 12, 2017, 10:56:45 »

Can I use bigger capacitors? I have a bunch of 100F capacitors lying around.
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TCWORLD

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Re: AstroEQ Basic Hand Controllers
« Reply #6 on: June 12, 2017, 14:50:08 »

@janne,

100uF is way to large. These are only for debouncing of the buttons. Anything in the 10nF-100nF range would be acceptable. Alternatively it will probably work ok without them.
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Tom Carpenter (AstroEQ)

pancho61

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Re: AstroEQ Basic Hand Controllers
« Reply #7 on: June 30, 2017, 22:17:18 »

Hello tom, i finished to made my own hand controller using a rotative switch for speed choice. I tried to connect directly to the st4 port and start the configuration to acess of test mod on EQMOD but when i do this astro EQ software can't read the EEPROM. How the hand controller work? does i need to configure something inside the astroEQ or carte du ciel?

Best regards

Damien

 
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TCWORLD

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Re: AstroEQ Basic Hand Controllers
« Reply #8 on: June 30, 2017, 22:35:31 »

Hi Damien,

I think you've misunderstood the purpose of the hand controller. It is not for use with the PC. It is designed to allow the AstroEQ to operate in completely standalone mode.

When you plug in the hand controller, the AstroEQ will cease listening to any serial communications and switch over to standalone. Consequently you wont be able to access the AstroEQ through EQMOD, nor via the config utility.

Once in standalone mode you can then press the NESW buttons to move the mount in whichever direction you fancy. The speed control then allows you to select between three speeds:

  • At the ST-4 speed (set through config utility). In this mode the mount tracks the RA axis at the sidereal rate, and the buttons change the speed relative to that.
  • At 2x sidereal speed. Again the mount tracks at the sidereal rate and the buttons have a relative speed
  • At the Go-To speed. In this mode tracking of the RA axis is disabled, so you can also set the speed switch to this mode to stop the mount moving if you require.

Once in standalone mode it will remain in standalone mode. If you disconnect the hand controller the mount will stop moving.

To switch back to PC mode, you have to disconnect the power/USB from AstroEQ and reconnect (power first as usual).

Kind Regards,
Tom.
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Tom Carpenter (AstroEQ)

Vincent

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Re: AstroEQ Basic Hand Controllers
« Reply #9 on: July 03, 2017, 07:55:56 »

Hi Tom,

/ this is my second message to you, I sent the first one through your website form (contact). /

My basic handcontroller tests failed, as I tried to check push buttons actions within RA/DEC values of EQMod panel...

I also thought the basic hand controller could be used when having all the setup connected to computer.

I wondered if it will be the same behavior with your future Extended Hand controller, regarding serial connection ?

Kind regards,
Vincent
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TCWORLD

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Re: AstroEQ Basic Hand Controllers
« Reply #10 on: July 03, 2017, 11:25:39 »

The hand controllers are specifically designed to allow the AstroEQ to be used in a standalone mode - i.e. without a PC.

If you want a hand controller for use with EQMOD, there are a great many options for gamepads and other things available - your best bet is to look up "EQMOD Gamepad".

The idea here was not to reinvent the wheel, but rather to make it possible for people to still use the motorised and tracking functionality of the mount when out and about without a computer. When I get around to designing the advanced hand controller, that again will be designed for standalone mode, but with the aim of implementing go-to functionality.
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Tom Carpenter (AstroEQ)

pancho61

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Re: AstroEQ Basic Hand Controllers
« Reply #11 on: July 03, 2017, 22:57:21 »

Hi Tom,

Thanks for your answer i guess, i did not correct understand the function or something is wrong inside my hand controller. as i test to move without pc and nothing move.

Other thing does i need to modify the pcb with the junction between jp1 and jp2 if have got v4.4 astro eq? If yes so i need to solder pin header on jp2 and jp1 and put direct wire between 1-1, 2-2 ...?

Damien
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TCWORLD

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Re: AstroEQ Basic Hand Controllers
« Reply #12 on: July 04, 2017, 22:27:47 »

@Damien, If you have a V4.4, you will need to modify the controller, yes.

First you'll need to connect JP1 and JP1, pin 1-1, 2-2 as you say.

Then you will need to connect a 1kOhm resistor between Pin 12 and Pin 31 of the ATMega162.

Finally connect a wire from Pin 1 of the ST4 port to Pin 12 of the ATMega162.
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Tom Carpenter (AstroEQ)

pancho61

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Re: AstroEQ Basic Hand Controllers
« Reply #13 on: July 05, 2017, 00:10:25 »

sorry i made a mistake, i have got the v4.6 of your board. today i solder pin 1,2,3,4 with wire between JP1 and JP2 but nothing change no mouvement.
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TCWORLD

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Re: AstroEQ Basic Hand Controllers
« Reply #14 on: July 05, 2017, 21:07:38 »

If you have the V4.6 board, you don't need to make any modifications. The V4.6 PCB already has all the necessary connections to use the hand controller.

Are you using the latest version of the firmware?

Also, I forgot to mention, when you plug in the hand controller, you need to move the speed switch to the ST-4 speed setting (the position which shorts the speed pin to GND). This will trigger the AstroEQ to detect the presence of the hand controller. You should then see the status LED start blinking at a constant rate indicating that the AstroEQ is in standalone mode.

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Tom Carpenter (AstroEQ)
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