[garybb1]

Hi
I am intending on using an SHT21 as my main temp sensor which has a max operating voltage of 3.6V
From looking at the schematic it looks to me as though jumper 1 sets the voltage for the VCC terminal of the I2C connections on the TX but not the SHT21/EI2C terminals.
If I want to use the SHT21/EI2C terminals for a longer cable run how is the voltage dropped to 3V ?
Thanks for any help anyone can offer

[f4aii]

it sends 5v on this port. There is possibility to go for 3.3v on the arduino.

[werk_ag]

Hi
I am intending on using an SHT21 as my main temp sensor which has a max operating voltage of 3.6V
From looking at the schematic it looks to me as though jumper 1 sets the voltage for the VCC terminal of the I2C connections on the TX but not the SHT21/EI2C terminals.
If I want to use the SHT21/EI2C terminals for a longer cable run how is the voltage dropped to 3V ?
Thanks for any help anyone can offer

Do you have a picture or link to the SHT21 module you are using?
Even if you grab the 3.3V from the Arduino 3.3V pin, keep in mind that the SDA and SCL lines have pull up resistors to 5V, so at least the sensor should be tolerant to this.

[garybb1]

Hi
I am intending on using an SHT21 as my main temp sensor which has a max operating voltage of 3.6V
From looking at the schematic it looks to me as though jumper 1 sets the voltage for the VCC terminal of the I2C connections on the TX but not the SHT21/EI2C terminals.
If I want to use the SHT21/EI2C terminals for a longer cable run how is the voltage dropped to 3V ?
Thanks for any help anyone can offer

Do you have a picture or link to the SHT21 module you are using?
Even if you grab the 3.3V from the Arduino 3.3V pin, keep in mind that the SDA and SCL lines have pull up resistors to 5V, so at least the sensor should be tolerant to this.

Thanks for the replies
As I understand it if I want to use a longer cable run I have to use the SHT21/EI2C terminals on the TX board.
The schematic shows a 5V supply at this terminal but the data sheets for the SHT21 show the max voltage this device can handle is 3.6V so I was worried I might damage the SHT21
Thanks

[werk_ag]

As I understand it if I want to use a longer cable run I have to use the SHT21/EI2C terminals on the TX board.

That's correct.

The schematic shows a 5V supply at this terminal but the data sheets for the SHT21 show the max voltage this device can handle is 3.6V so I was worried I might damage the SHT21

What matters is if the module where the your SHT21 is installed, is suitable to be powered by 5V or not. All SHT21 chip are 3.3V, so its the module that have some extra components to act as level converter.

Check the specs of the module you have. If it says that can be powered by 5V, you can use it safely.
Post a picture of you module, it may help.

[garybb1]

Thanks Werk
That explains what I wanted to know
 I will check the spec of the module I am using
So what is the purpose of jumper 1
Thanks

[werk_ag]

So what is the purpose of jumper 1

Hi,

Can you please tell me which TX board version are you using?
There are some ancient (and rare) TX boards that have an 3.3v / 5V jumper selector for the SHT1X sensor.

[garybb1]

So what is the purpose of jumper 1

Hi,

Can you please tell me which TX board version are you using?
There are some ancient (and rare) TX boards that have an 3.3v / 5V jumper selector for the SHT1X sensor.

[garybb1]

Hi
I am using a TX 3.11 which I purchased a year or so ago
I have only just got round to starting to construct it due to work commitments

[werk_ag]

Nice TX board,    there are only 20 of those boards. The two TX boards I still have in use, are also v3.11