Need to know about autostar serial protocol

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StarLord101
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Need to know about autostar serial protocol

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Post by StarLord101 »


my most recent "hack"/tinker I have been pursuing a LOT over the last few days due to the Covid crap: Trying to create and setup a homemade serial to wifi setup using a little ESP8266 Wemos d1 mini. I've dealt a lot with serial communication stuff with my synchronized christmas light show in recent years, but I'm not entirely sure if I have it right in terms of feasibility with this.



The idea is this: I hate the flakey usb to serial adapters, and I would love to be able to control the scope as if I was physically connected to the com port, but wirelessly. I used these wemos d1 mini boards to run 800 pixels each for my Christmas light show, all over wifi sending serial commands through a firmware I loaded on to it from github called FORKINEYE. I kept seeing these mentions of serial to wifi adapters for scopes that you basically plug in to the HC port,, then you connect to the network the dongle is broadcasting from your pc, and I guess the result is a wireless serial bridge where the scope and the pc act as if it was physically attached via the com port. Those units are also ridiculously overpriced. I had a bunch of these wemos d1 boards leftover, so I started looking into it, and the most promising lead I had was a firmware called ESP-LINK for free on github. Reading on threads and the page, to my understanding, it would accomplish exactly what I was after: Create a serial to wifi connection that would allow you to access the serial device wirelessly with a esp8266 board as if you were physically connected. So I got that setup and loaded on the wemos and configured it. I can see the network and connect to it from the pc and set the settings from it's config webpage.



I wired up a meade 505 cable using a 4p4c phone handset cord and this pinout
Image

With one exception. Since I wasn't going to be connecting to a serial port physically, instead of connecting the cable to a db9 connector, I ran the wires directly to the pins on the wemos d1 mini.
Image
Pin 1 from the HC side (rx) connected to the TX pin on the wemos (GPIO1), Pin 2/TX from the HC side connected to RX pin on the Wemos (GPIO3), and pin 4 from the HC side connected to Ground on the wemos (GND). So far so good. I power it from the usb port with a 5v supply since the wemos can shift it down to 3.3v. So I start up the mount, everything is good on the hand controller, but as soon as i plug in the rj cable into the base of the HC, the writing on the screen goes completely blank but it remains turned on and backlit. But there is no response whatsoever from the controller, and the network that was visible from my pc from the wemos disappears as if offline. If I unplug the cable, sometimes the screen on the hc stays blank but backlit until I reset it and then it's normal again, sometimes it's back to normal as soon as I unplug the cable. The wemos network is then back online as well. Any thoughts?

One thing I wondered: another thread mentioned this kind of setup with a celestron and a different Esp device. But he mentioned he had to include an rs232 to ttl converted for it. That's celestron, and I'm trying to do this with a meade lxd75 and an autostar 497. I can't seem to find out if this is also necessary or if the serial output is +12v, - 12v....or 0v-3.3/5v for signal
LXD75 GEM mount used with 90mm Meade Refractor, 102mm Celestron reflector, and a deforked Original Meade ETX Mak
Canon T1i stock
Various modified or 3d printed DIY enhancements or tweaks
Does a kids sunglass lens count as a fancy filter? Cause I have lots of those :)
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Xio1996 Great Britain
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Re: Need to know about autostar serial protocol

#2

Post by Xio1996 »


Hi StarLord101,

The ESP32 will be using TTL Serial but the port on your hand-controller (if it is the same as a NextStar controller) is RS232. You will need a converter.
This explains the concept on the SparkFun website https://www.sparkfun.com/tutorials/215

I did a similar project using a Bluetooth to serial demo board (https://www.ebay.co.uk/i/254349811142?chn=ps). Then I could use SkySafari on my Android tablet to control my scope.

Have fun, but be careful, telescopes are expensive beasts.

Xio1996
EAA Observing from the Isle of Wight, UK
Telescope: Celestron CPC800, NexStar 4se - Camera: Altair Astro Hypercam 294c PRO, ZWO ASI 533MM
Software: CPWI, SharpCap, Stellarium, TheSky, SkyChart, Starry Night 8, Aladin, ASTAP and AstroPlanner.
YouTube 'EAA with an 8-inch SCT' https://www.youtube.com/@Xio2011
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