Data lines are not 5V tolerant. It won't burn out the chip (at least not right away) but you'll get unexpected resets, etc. until you put in a voltage divider or level shifter on the RX line (I used a TI PCA9306).
Thanks for the advise. I only need to drop the voltage from the pin that sends the signal from the arduino, right?UPDATE:Just tested this by adding a voltage divider to arduino TX line. With the VD the blue LED which indicates traffic stays permanently on and I get no response from the module when I send AT commands. I'm using firmware 0018000902-AI03Vin == Arduino TXVout == ESP RXR1 == 1KR2 == 2K
Are you tieing CH_PD and GPIO0 high and putting a pullup resistor on RST? Otherwise the module won't boot.
Data lines are not 5V tolerant. It won't burn out the chip (at least not right away) but you'll get unexpected resets
Re: ESP-05Are you using a voltage divider from TX on the Arduino, otherwise you are giving the ESP-05 too much voltage on its RX pinYESAlthough it may work for a while you stand a chance of damaging the module if you don't use a voltage dividerWhen you say you powered up the module, what did you power it with, the 3.3V from the Arduino doesn't deliver enough current to guarantee correct operation of the device as it takes between 50 and 200mA when working, which is more than the Arduino can supply.NO if you read my post you'd see i stated it was exteranlly powered. and YES with 3.3vAs you can't easily access any of the GPIO lines in order to upload new firmware etc into the module, you are really stuck with whatever unknown firmware came with the module.THERE ARE NO GPIO LINES ON THIS MODEL SEE THE ATTATCHED JPGIf its the Old AT command set version, it works at 115200 but the new one I think defaults to 9600 (but can be changed with an AT command)Personally, I would not buy this module because the lack of connections makes it very limited and problematic to use. I BOUGHT THIS MODEL FOR 2 REASONS 1 THE EXTERNAL ANTENNA, 2 PRICE.ESP-03 seems quite popular and if you want to do anything apart from connecting to the Arduino, you need a ESP-12 or similar, as even to use low power mode requires access to more of the GPIO pins.and the ability to reflash the firmware is virtually essential at the moment as it changes all the time.If you have a very steady hand, you could solder extra wires directly to the device (I had to do this on an ESP-01 and and ESP-03) but its very hard to do !