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why am I getting a stream of rubbish characters

PostPosted: Wed May 06, 2015 5:14 am
by CraigB
I successfully set up an Arduino uno and ESP8266 and was uploading data to thingspeak for a day or so.Then the update stopped working. On connecting to the arduino with ESP8266 running at 9600 baud I can send AT commands and get sensible results but am also getting a constant stream of rubbish characters that I assume are coming from the ESP8266.

AT+GMR returns
AT version:0.21.0.0
SDK version:0.9.5

AT+RST returns
OK
ü„ÔþLoÜAæΖtàÆP„HA1åˆ1ƒˆÀ€iäüøøøøüøøøøúøøøàøøøøÀÿG
Ah-Tinkdr Dechnology Co. Ltd.

invalid

AT+CWMODE? returns
+CWMODE:1

OK
ÿÿþÿþþþÿþÿÿþÿþÿÿÿÏþÿæÿþÿÿÿ

And the stream of rubbish characters keeps flowing.

Can anybody help explain what is going on?
How can I stop the flow of characters?

I should mention I'm using a LD33V voltage regulator to supply 3.3V and have a voltage divider on the Tx line from the Arduino to the Rx on the ESP8266.

Thanks

Re: why am I getting a stream of rubbish characters

PostPosted: Wed May 06, 2015 3:49 pm
by kenn
When I started using ESP8266s, I was getting some garbage characters on the terminal, and most updates failed. I found that it was because of a RS232 to TTL converter I made (using MAX232) - I had missed one connection. When i fixed that, no more garbage characters, and every flash succeeded.

Based on that experience, it would seem that you might also be having some sort of serial connection or transmission issue. An oscilloscope is a big help when chasing this sort of problem.

Re: why am I getting a stream of rubbish characters

PostPosted: Thu May 07, 2015 3:45 am
by CraigB
The serial connection from the ESP8266 is a straight jumper wire to pin 10 using serialsoft. I've checked as best I can that the connections are good so don't think that is the problem. Also the ESP8266 does manage to send sensible responses to AT commands then reverts to a stream of garbage characters.

Re: why am I getting a stream of rubbish characters

PostPosted: Thu May 07, 2015 4:12 am
by CraigB
AH HA!
It was a bad connection on the breadboard supplying 3.3V to either power, rst or CH_PD. Now I can move on to monitoring my solar hot water system efficiency.
And maybe buying a better quality breadboard.