AstroEQ Discussion Board

AstroEQ R&D => Hardware Development => Topic started by: TCWORLD on April 10, 2017, 01:13:55

Title: AstroEQ Basic Hand Controllers
Post by: TCWORLD on April 10, 2017, 01:13:55

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,
Title: Re: AstroEQ Basic Hand Controllers
Post by: adfuller 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.
Title: Re: AstroEQ Basic Hand Controllers
Post by: TCWORLD 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,
Title: Re: AstroEQ Basic Hand Controllers
Post by: TCWORLD on April 20, 2017, 20:42:11
As well as the ST4 port, you will also need to make the following connections:

Title: Re: AstroEQ Basic Hand Controllers
Post by: paul_astrix on April 29, 2017, 16:38:34
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.

Title: Re: AstroEQ Basic Hand Controllers
Post by: janne on June 12, 2017, 10:56:45
Can I use bigger capacitors? I have a bunch of 100F capacitors lying around.
Title: Re: AstroEQ Basic Hand Controllers
Post by: TCWORLD on June 12, 2017, 14:50:08

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.
Title: Re: AstroEQ Basic Hand Controllers
Post by: pancho61 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


Title: Re: AstroEQ Basic Hand Controllers
Post by: TCWORLD 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:

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,
Title: Re: AstroEQ Basic Hand Controllers
Post by: Vincent 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,
Title: Re: AstroEQ Basic Hand Controllers
Post by: TCWORLD 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.
Title: Re: AstroEQ Basic Hand Controllers
Post by: pancho61 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 ...?

Title: Re: AstroEQ Basic Hand Controllers
Post by: TCWORLD 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.
Title: Re: AstroEQ Basic Hand Controllers
Post by: pancho61 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.
Title: Re: AstroEQ Basic Hand Controllers
Post by: TCWORLD 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.

Title: Re: AstroEQ Basic Hand Controllers
Post by: Vincent on July 06, 2017, 10:45:48
Thank you for your answer.

I only had a 2 positions switch available, so formerly I did not wire the ST4 speed...
Anyway my handcontroller now works good, with ST4 and GOTO speed.
Title: Re: AstroEQ Basic Hand Controllers
Post by: Vincent on July 07, 2017, 10:10:10

I only noted one thing with standalone mode.

When I powerup in standalone mode (Handcontroler speed switch on "ST4 speed" position) then sideral tracking starts.

If I decide to slew at higher speed, I select "Goto speed" position, then sideral tracking stops waiting for NESW push buttons orders.

I have to select back "ST4 speed" position, in order sideral tracking starts again.

Is it expected behavior ?
I would find nice to get sideral tracking always on (ie independant of speed switch position) ?

Thank you
Title: Re: AstroEQ Basic Hand Controllers
Post by: TCWORLD on July 07, 2017, 20:18:21
Hi Vincent,

It's by design. The theory was if you are moving around at go-to speed you wouldn't want the mount to be tracking (maybe I'm wrong?). It also means that if you unplug the hand controller the motors will stop moving (go-to speed is set essentially by floating the speed pin).

With the 2x speed and ST4 speed selections the mount will continue tracking, so essentially you would use Go-To speed to reach a ballpark location, then 2x speed to move in to the target.

Kind Regards,
Title: Re: AstroEQ Basic Hand Controllers
Post by: igorb on December 22, 2017, 10:13:52
I'm in a process of building a hand controller and I have two questions. At the beggining of this topics, it is said that 2k resistor should be soldered between pin1 and pin2 of the st4 port to switch the speed to 2x sidereal. But on the schematics it is 3.9k resistor. I guess it will work in both cases but I need confirmation just to be sure. I also want to know if its possible to predefine some other speed for that switch position instead 2x. I'm using wide field telescope on my mount so 2x sidereal is quite slow for centering the target.

And, btw, thank you once more for your efforts and this magnificent project.
Title: Re: AstroEQ Basic Hand Controllers
Post by: TCWORLD on December 22, 2017, 22:13:00

For the resistors it is a bit of trial and error to make it reliable, that's part of why I haven't sold any of the hand controllers I had made.

The idea is that you get three speeds - Sidereal, 2x Sidereal, and Go-To. So you can use the go-to speed to get close and then the 2x speed to get nicely centred. The main reason that speed was chosen is it simplifies the code (I don't have to run the acceleration/deceleration routines for 2x speed). But I can look in to it (e.g. make it 4x speed or selectable) if it testing shows it to be useful - I haven't had a chance to get my scope out for over a year.

Kind Regards,
Title: Re: AstroEQ Basic Hand Controllers
Post by: igorb on December 23, 2017, 10:50:12
Ah, I see. But, for widefield viewing, if it is set at 4x or 8x speed, tracking is not even neccessary (while centering, that is). After centering the target you turn the switch back to its first position (sidereal tracking speed). So, what I intend to do now if  this doesn't work, is to set goto speed to 8x prior to obseving session and use switch position 3 for centering but then I loose faster goto speed for moving the mount to the new target. It is not a big deal as I still have both of my hands for that :)
But if it is complicated, please ignore this post, as, for me, the primary function of the AstroEQ is for imaging and for that it is, ofcourse, connected to the PC.

Best Regards and merry Christmas!
Title: Re: AstroEQ Basic Hand Controllers
Post by: PhilCrompton on February 05, 2018, 21:32:57
Hello as part of my Astro-EQ6 conversion I wanted to re-use the old hand controller that came with the non-working, non-goto EQ6 that I started with. This was a relatively easy hack. I simply de-soldered and remove all the components except the 4 momentary switches and the slide switches from the original controller. I also un-soldered the curly cable which just happened to have a 6 contact RJ11 (also known as an RJ12) connector.

You can't see it in the picture but the 3K9 speed control resistor replaced the left-hand resistor under the ribbon cable you can see in the attached picture. I stripped back the outer insulation of the cable to expose the two unused wires and reconnected the individual wires as you can see the picture. I also added a blue and brown jumpers that you can see crossing the old IC location. The de-bounce capacitors were soldered directly to the back of the momentary switches.

The original 2x, 8x, 16x switch controls the speed. The other switch does nothing. Make sure you also remove the LED from the centre of the RA/DEC keys otherwise the high-speed slew doesn't work.

Title: Re: AstroEQ Basic Hand Controllers
Post by: barbwire78 on February 23, 2018, 18:32:58
Hi, this is my version of hand controller:
( ( ( ( ( (

Everything work fine :)

Title: Re: AstroEQ Basic Hand Controllers
Post by: igorb on March 01, 2018, 19:20:41
Nice  8)

Where did you get those low profile momentary pushbuttons if I may ask? I'm working on hand controller too but cannot find suitable switches  :-\

Title: Re: AstroEQ Basic Hand Controllers
Post by: on March 02, 2018, 00:02:30
Perhaps not exactly the same, but I bought 4 of these from eBay, 3.69 for 4

I've got them fitted in a project box RX2010 from this listing, the box is quite small, but there's just enough room to put them in a star (NESW) pattern
Title: Re: AstroEQ Basic Hand Controllers
Post by: igorb on March 03, 2018, 10:07:27
Thanks!  ;)

Now what colour to choose  :P
Title: Re: AstroEQ Basic Hand Controllers
Post by: jurek0605 on April 08, 2018, 15:28:39
Hello, I have astroeq for arduino mega2560, how to do speed control on it?

Title: Re: AstroEQ Basic Hand Controllers
Post by: grozmaistor on October 01, 2019, 08:53:02
Hello Tom,
I am going to make the basic hand controller.
I have at home many parts but lack a 3.9KOhm resistor. But I can make it 3.93KOhm. How crucial :-) will it be for the system to use a slightly stronger resistor, or I have to buy 3.9KOhm one.

Title: Re: AstroEQ Basic Hand Controllers
Post by: TCWORLD on October 03, 2019, 21:14:20

3.93k should be fine. At a rough guess anything within ~10% should be ok. There's quite a lot of chip-to-chip variation in the internal pull-up resistors of the ATMega anyway, so you may find that the resistor value needs to be adjusted.
Title: Re: AstroEQ Basic Hand Controllers
Post by: grozmaistor on October 12, 2019, 18:51:49
This is my version of the hand controller with the 3 position switch. It works.
Title: Re: AstroEQ Basic Hand Controllers
Post by: johnyjf on November 13, 2019, 10:26:22
Hi Tom,
Where can you buy the Hand Controlleryou show?  It looks very neat.A quick look on eBay showed many thousands of car key fobe options but I couldn't find one of there.