Pololu Robotics & Electronics
Menu
My account Comments or questions? About Pololu Contact Ordering information Distributors

WiFi connection to Orangutan SV-328p


#1

I was searching around … but did not find general answer.
I’ve build robot (SV-328p) that controls DIY AZ/AL telescope pedestal mount. It runs 2 steper motors currently. I have unused ports A and B … but I may used one of them for focus control or autoderotae ( astrophotography ) or both.
Data input is via pushbuttons.
Next step: made it a remote system computer<=>orangutan, biderectional link, so need for a radio link such as WiFi.
The advice needed:

  1. I believe that I can talk to Orangutan via USB - i.e. same way like to talking to SPI programmer. True or False ???
  2. What WiFi module, piece of “shield” or may be even one of the WiFi usb dongle ( Linksys,Cisco,…etc…??? would be usefull ???
  3. What protocol would be more suitable I2C or USB for data exchange ???

may be there are some answers already but I could find them.

Thanks and regards Kris.


#2

Another computer can easily “talk” to the Orangutan through the serial port, via a USB serial port adapter. Pololu ISP programmers, like this one pololu.com/product/1300 have such an adapter built in. Once you have decided on a communications protocol, the USB adapter could be replaced with a radio link like a pair of Wixels or Xbees that implement a “wireless serial” connection.

Implementing a WiFi connection would take specialized modules and a lot of code. Other much simpler alternatives include using the very inexpensive 315 or 433 MHz transmitter and receiver modules, and (if you are using the Arduino environment) the VirtualWire library for error-checking data transmission. ebay.com/itm/433Mhz-WL-RF-Tr … 0717845396

If you go that way, any pins can be used for data transmission. Other radio options (Xbee, NRF24L01, etc.) require the use of the I2C, SPI or serial port and more complicated software.


#3

Thanks for your advice.
OK … I am using Pololus programmer ( mixed name (SPI-IPS) in my original post … :slight_smile: for loading software in to Orangutan).
Have to look furtherr at “serial” Pololu libs to find out routines used for hex loading.

On Aliexpress and DX.com there are numerous WiFi/RC parts - so small, build in mini/micro USB plug … miniaturisation is mind blowing these days.

Probably jus simple terminal RS232C like emulation will do, as message are very short, what ever is on LCD will be send to computer, from computer for eaxmale “RA045623” or “Y” … “N” … or code assigned to BUTTON_x.

Thanks for your time, much apprecited … Kris


#4

Got ESP-05 WiFi module and trying to talk to it from minicom on Linux box.
Using PGM-03A as USB to TTL converter. Works fine.
ESP-05 connected to supply … I can see it’s SSID and can give it IP of choice.
The search on internet for electrical specs of ESP-05 … could not find.
The questions:
What is the output level or what it suppose to be on RxD pin ???

On osciloscope I can see just a little drop like couple hundred milivolts. This pin suppose to pull down the emiter of level translating transitor ( 3.3V to 5v) to less than base bias voltage.
Base of transistor is connected to 3.3v via 22k resistor. Collector resistor 5k6 to 5v line, and colector connected to PGM Rx pin.
This should work if ESP-05 RxD pin puls down to ~ 0v or to less than base bias.
ESP-05 TxD pin is driven from TTL logic via voltage divider 5v->3v.

So far can not talk to WiFi gizmo via USB from computer.

Any ideas, links to relevant info ???

Regards Kris


#5

Little progress.
Designed ESP-05 WiFi module interface to Pololu PGM03A so can talk to WiFi module.
Circuit diagram, screen shot are there:
drive.google.com/open?id=0B_w7M … authuser=0
drive.google.com/open?id=0B_w7M … authuser=0

From computer can talk??? to WiFi module via USB (/dev/ttyACM1) using minicom. The Orangutan should be able to talk to WiFi via SPI or D0,D1 - that is I hope for.
ESP-05 suppose to understand AT commands. So far nothing happens.

Trying to figure out how to talk from ??? via WiFi to (ESP-05) meaning sending data from “the World” to … hopefuly Orangutan.

The basic idea is:
Orangutan program waits/scans for push “button variable”, serial interrupt routine sets button=recived_button ( i.e. value corresponding to button A,B,C) and things happen … one day!!!


#6

Designed ESP-05 WiFi module interface to Pololu PGM03A so can talk to WiFi module.
Circuit diagram, screen shot are there:
drive.google.com/open?id=0B_w7M … authuser=0
drive.google.com/open?id=0B_w7M … authuser=0

From computer can talk??? to WiFi module via USB (/dev/ttyACM1) using minicom. The Orangutan should be able to talk to WiFi via SPI or D0,D1 - that is I hope for.
ESP-05 suppose to understand AT commands. So far nothing happens.

Since origiinal post I made simpler USB-ESP05 interface. It is here:
goo.gl/photos/nQ3x67FfdyQZZj8H7

Still can not talk to ESP05, can see SSID on the net, can connect to it but can not talk to it form computer via USB via PGM03A.

Is ther any one that can help ??? please.


#7

Hi, Kris.

I merged the two threads that you created, since they both seem to be asking about the same system and issues.

It is not clear to me what parts of your system are working and how everything in your system is connected (even with the schematic you posted). Could you very clearly state what you have connected to the wifi module, what you have connected to the programmer, and what you have connected to the Orangutan? Also, could you clearly state what two components you are having trouble communicating directly between?

If you post pictures of your setup along with the descriptions of what components are connected to each other, that would probably also be helpful.

-Claire


#8

Thanks Claire.
The connectivity is as follows:
Computer, linux box connected to PGM03 via USB - same as for programming Orangutan.
Computer communication program uses /dev/ttyACM1 - as PGM is used as USB serial port for “talking” to other hardware - interface(s) shown which translates TTL (5v) to 3.3v.
So there for I have Rx and Tx lines from USB suitable for communication with WiFi module being ESP05.

  1. This is step 1 - all 3 components shown on circuit diagrams making USB serial wiFi terminal which can be used with any computers comms software to send data over radio waves.

  2. Now I can send and recive data from WiFi network, send commands to WiFi module to set up paramaters and e.t.c…e.t.c …
    I can write program or app for tablet/phone or use like minicom on PC to send and recive data strings. For example send: B=button_A string.

  3. Discard PGM module from the circuit(s) diagrams and connect Tx/Rx lines to Orangutan either SPI pins or D0, D1 pins.

Run program on Orangutan which will send LCD buffer data via WiFi to remote computer. Same like - pressing button A on Orangutan and print response on LCD.
From remote computer I send string which is value of say button_C. This will cuse Orangutan to do exactly what it will do when button C is pressed, and may send LCD data back to remote computer.

  1. It mouth full description … Right now I have Orangutan controling telescope AZ drive. Pressing buttons on Orangutan is … well, OK but when is cold outside much nicer is to saty inside and enjoy view from camera ( Wifi streaming installed on telescope ) on 50" 4k TV screen :smiley: .
    Jumping telescope from star to star is also much easier using tablet from comfortable arm chair … don’t you think so ? :smiley:

At the moment I am having issues with ESP05 module itself, for some reason I am not getting respons to AT commands. It could be blown up Tx pin. Getting few more modules from different supplies …

I hope it clarifies the story a little.

Thanks for your time, kind regards Kris


#9

Latest news:

  1. From my experience in electronics … I washed the ESP 05 module in alcohol (metho) this removes/dissolves flux.
  2. Put it back in to breadboard … and … it works
  3. So far it talks back to computer running xc comms program:

session snippet:

� �
[Vendor:www.ai-thinker.com Version:0.9.2.4]

ready
AT

ERROR
ATE

ERROR
ATE=1

ERROR
ATE1

OK
AT+GMR

ERROR
AT+RST

ERROR
RST
wrong syntax

So now tg find out or figure out which commands ESP 05 accepts and than can write a picece of code for Orangutan.
Still a bit confused about washing this module … sounds like there was a leakage somewhere.

Thanks for your time, every one comming up with questions/suggestions.

Regards Kris