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DIY integral WiFi for iOptron 8408 hand controller

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#1 kingjamez

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Posted 30 May 2016 - 09:14 AM

I wanted to control my ZEQ25  (now CEM25) with SkySafari Pro but didn't want to pay the high price for a SkyFi or Starseek. $150+ seemed a bit nuts to me.

 

I started by building a WiFi to Serial converter using a Raspberry Pi. That worked fine but required external power and more wires going into the hand controller.

 

I then started working with the ESP8266. It's a small WiFi enabled chipset that has a built in microcontroller. People have done amazing things with the ESP8266. A bare board costs about $3.00 and you need a few external components to make it run / program. Instead of using the a bare module, I decided to pay twice (!!) the price and buy an ESP8266 board that had all the external parts built in. The best board I could find is the WeMos D1 Mini. mini_v2.jpg

It requires no external components to program via USB and has all the built in SMD parts to make the ESP8266 run when programmed. For software a project called ESP-Link by jeelabs already did exactly what I wanted. It creates a WiFi to serial bridge and also puts a webserver on the ESP8266 that allows you to change the settings from a webpage. Neat! 

 

The next step was to open up the iOptron 8408 hand controller. There is a ton of extra space inside the hand controller. I found a bare spot on the board and used some double sided tape to secure the D1 Mini board. Initially the board was to thick to fit inside the case so once programmed, I removed the micro-usb connector to make the D1 Mini board thinner. That gave me enough room to tape the board down and still screw the hand controller back together.

 

I traced out the RJ9 connector on the board to a Max3232 clone chip that converts RS232 to TTL for processing by the ARM microprocessor that is in the hand controller. Since the ESP8266 puts out TTL level signals I bypassed the RS232 converter and soldered the Tx and Rx lines to the TTL side of the Max3232 that went straight to the ARM chip. ESP_8108.jpg

 

All that was then required was to find 3.3 volts and route power to the ESP8266. I checked the specs on the switching power supply that is used to convert 12 volts from the battery powering the mount to 3.3 volts for the ARM and MAX3232. It's rated up to 1.5 amps which means there is plenty of spare power. The ESP8266 takes about 170ma at max transmit power.

ESP_8108_all.jpg

 

You can see in this picture a small bluetooth to serial module that would do the same thing only over bluetooth. You'd power it and hook it up to the same lines as the ESP8266. I haven't tried it since I use apple devices and bluetooth control won't work with SkySafari, so do that at your own risk. 

 

After I buttoned it all back up, everything works exactly as it should. I can control my mount from my iPhone with no additional power supplies or wires, all for less than $10.00 and a few hours of work.

 

-Jim

 


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#2 tjugo

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Posted 30 May 2016 - 11:26 AM

Excellent! Thanks for sharing your project!



#3 corduroy

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Posted 30 May 2016 - 11:54 AM

Cool,  Thanks for sharing!.  Does performing this modification preclude you from using the serial port connector to go back to a  wired connection to a pc?


Edited by corduroy, 30 May 2016 - 11:55 AM.


#4 kingjamez

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Posted 30 May 2016 - 12:15 PM

Thanks guys. Corduroy: I can still use the wired serial side. I made sure I could still use the wired serial connection so that I can update the hand controller via a computer. That's the only reason I didn't remove the Max3232 chip.

-Jim

#5 corduroy

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Posted 30 May 2016 - 12:24 PM

Ahh. ok, Are leads on the Max3232 and capactor still connected to the board?



#6 kingjamez

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Posted 30 May 2016 - 12:47 PM

I'm sorry, I don't understand the question. The hand controller still functions 100% like a normal unit, no connections are interrupted. The connection on the capacitor is just a convenient place to pick up +3.3v.

 

-Jim


Edited by kingjamez, 30 May 2016 - 12:55 PM.


#7 budman1961

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Posted 30 May 2016 - 09:20 PM

How about on an 8407 handbox?

 

Great work by the way......the community appreciates your work!

 

Andy



#8 Dustin Smith

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Posted 30 May 2016 - 09:47 PM

I see a business opportunity -- have people send you their controller, you mod them for a fee and return them..proceeds go towards new gear!

 

Dustin



#9 kingjamez

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Posted 31 May 2016 - 06:46 AM

Budman: I haven't looked at an 8407 controller, but if it can talk RS232 it's likely that this technique will work. For controllers that have less extra space inside, it's possible to get an ESP8266 in a smaller form factor with a little more work.

Dustin: Perhaps, but I'm hoping that people can do this on their own and save a bunch of money!

-Jim

Edited by kingjamez, 31 May 2016 - 06:47 AM.


#10 fmeschia

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Posted 03 July 2016 - 12:10 PM

Great thread, thanks for posting it! I am going to do the same with my iEQ45 Pro. Did you have to set a specific baud rate in your serial bridge?



#11 fmeschia

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Posted 03 July 2016 - 01:56 PM

Also, based on the two 1 Ohm resistors (R14 and R15) in parallel, I think that the step-down regulator is set up for a max output current of 300 mA. Did this actually prove enough to power the WiFi module, or did you have to change the current sensing resistors? 



#12 kingjamez

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Posted 10 July 2016 - 12:31 AM

Hi fmeschia, sorry for taking so long to respond, I haven't had near the time I wish I had for astronomy lately.

 

Yes, I modified the make file to automatically set the baud rate at 9600 N 1 IIRC. If it doesn't come up at 9600 you can set it in the web gui of ESP-Link.

 

I'll have to go back and look at my photos / RE of the board to answer your current question. If it is indeed set at 300ma max, I'd want to change that. That said, it's been working for me with no issues for over a month now and having had it out on multiple occasions I haven't had a power problem. I'll investigate this further as time allows.

 

Good catch.

 

-Jim



#13 fmeschia

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Posted 10 July 2016 - 12:56 AM

Thank you very much, Jim!

Francesco



#14 Chris1

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Posted 11 July 2016 - 06:59 AM

Hi All

 

Interesting reading here, many thanks. I'm new to cloudy nights BTW, just registered.

 

I'm wondering if anyone could please tell me the part number for the 3.3v regulator on the 8408 hand controller?

Tantalizingly, the images here show the 8 pin surface mount regulator, but I am unable to see the part number!

 

I have one in need of repair, lets just say 'the smoke has decided to come out' of this one!! Literally blown itself apart, so I am unable to see its part number.

 

I could change it if I knew the part number, so many thanks if you can help.

 

Good Seeing.

 

Chris

 

 



#15 fmeschia

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Posted 11 July 2016 - 10:36 AM

Unfortunately I don't have a 8408 HBX, but if it may help you I reverse engineered the voltage regulator of my iEQ45 Pro main board. It has a two-stage regulator: first a 5V DC-DC step-down converter (with a MC34063A switcher), followed by a linear 3.3V stage (with an AMS1117 linear regulator).

 

Francesco



#16 fmeschia

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Posted 11 July 2016 - 12:26 PM

I took another look at the pictures Jim posted. It looks like the handbox has a single-stage switching converter, set for 3.3V output. The switching IC seems a MC34063A, but I'm not 100% sure I read that correctly.


Edited by fmeschia, 11 July 2016 - 12:27 PM.


#17 Chris1

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Posted 12 July 2016 - 03:05 AM

Many thanks for looking, appreciated.

 

I would much rather be 100% sure what the IC is before I change it.

 

I'll look up in the datasheet and see if the circuit in the hand controller looks similar. The two 1 ohm resistors should tell me.

 

Maybe someone with an 8408 would be prepared to take a look inside theirs for me??

 

Thanks again.

 



#18 corduroy

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Posted 12 July 2016 - 09:02 AM

@kingjamez  -  do you have a link with simple instructions / software needed to program the ESP8266 using a windows pc?  Thanks



#19 fmeschia

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Posted 12 July 2016 - 09:22 PM

I just looked inside my 8407+: the DC-DC converter chip is marked ST 063AC (so I think it's an MC34063AC), the package looks like a SOP-8.



#20 Chris1

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Posted 13 July 2016 - 05:09 AM

Hi

 

Thank you. You are absolutely correct, I ended up emailing iOptron, the Tech told me it was an EK245!! :) but did send me a picture which clearly show 063AC

 

8408 uses the same regulator MC34063ACD-TR as the 8407+ then.

 

I appreciate you taking the time to look inside your 8407, great stuff.

 

Good Seeing

Chris

 

 



#21 corduroy

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Posted 13 July 2016 - 11:49 AM

Anyone know where the WeMos D1 Mini is available in the US?



#22 fmeschia

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Posted 13 July 2016 - 11:51 AM

Anyone know where the WeMos D1 Mini is available in the US?

 

If you search eBay for US vendors you usually find a few. The D1 mini is easy to program and nice, but there are also other ESP8266 boards that would do. 



#23 fmeschia

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Posted 16 July 2016 - 07:10 PM

Following in the path that Jim opened, I have designed and built my own WiFi adapter. I also used an ESP8266-based board (but the simpler ESP-01 one), and the same esp-link firmware. But I decided I didn't want to void my mount's warranty by modifying its hardware; instead, I built an external adapter that takes power from the iOptron Port, converts it into a 3.3 V supply with a DC-DC converter to power the WiFi module, and talks to the mount serial port via a MAX3232 TTL-to-serial converter.

 

It is certainly less neat than Jim's solution, but I am glad I did it so I didn't have to modify the mount hardware.

 

Here is a video in which you can see my device and an iPad running Sky Safari that controls my mount through it:

https://youtu.be/_uhQ0Lzc3-E

 

Francesco


Edited by fmeschia, 17 July 2016 - 12:02 PM.


#24 corduroy

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Posted 24 July 2016 - 10:31 AM

Hello, has anyone else done this yet?

 

 

I purchased the ESP8266 WeMos D1 Mini V2 and it's currently in transit. I am a bit confused with how to load the firmware package. I am linux noob and just have a Windows machine. I have a few questions if someone could kindly help.

 

1) Do I need to install Arduino? and are these the correct instructions?
http://www.wemos.cc/...in_arduino.html

 

2) Are these the instructions to install esp-link? I believe this is done via python but I am not sure how to connect python to the Wemos D1
https://github.com/j...p-link/releases

 

3) How do I determine if everything is working before I remove the USB connector? ... I guess I could leave the hand controller back off, power the mount, and try to connect skysafari...



#25 fmeschia

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Posted 24 July 2016 - 12:31 PM

Hello, has anyone else done this yet?

 

 

I purchased the ESP8266 WeMos D1 Mini V2 and it's currently in transit. I am a bit confused with how to load the firmware package. I am linux noob and just have a Windows machine. I have a few questions if someone could kindly help.

 

1) Do I need to install Arduino? and are these the correct instructions?
http://www.wemos.cc/...in_arduino.html

 

2) Are these the instructions to install esp-link? I believe this is done via python but I am not sure how to connect python to the Wemos D1
https://github.com/j...p-link/releases

 

3) How do I determine if everything is working before I remove the USB connector? ... I guess I could leave the hand controller back off, power the mount, and try to connect skysafari...

 

 

In my project I used the ESP-01, so the original topic starter can probably answer better than me for the WeMos D1, but here is my 2 cents:

  1. No, you don't need Arduino if you use a pre-built release of esp-link, like this one: https://github.com/j...ases/tag/v2.2.3
  2. Yes those are the instructions, depending on the release you want to use. You are correct, there is a Python tool (esptool.py) that you need to use to upload the firmware. You will first need to download and build esptool.py (sources here: https://github.com/t...nventor/esptool). What operating system are you using on your computer?
  3. I would recommend you first use the esp-link web interface to see if esp-link is correctly working, and configure the serial port for 9600 bps, 1 stop bit, no parity. Only then you can try to solder the module to your hand controller. 



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