TMP421 temperature sensor

Interfacing hardware, sensors, output drivers, chips.
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abeza
Posts: 4
Joined: Fri Feb 18, 2011 12:32 pm

TMP421 temperature sensor

Post by abeza » Fri Feb 18, 2011 12:46 pm

I just purchased a TMP421 temperature sensor and would like to
connect it to my picaxe 12M2 processor. The sensor came with a 4 pin header,
there are 8 pins associated with the sensor and I have no idea of what sensor pins
to use with the 4 pin header and what they represent in terms of DXP, DXN, A!, A0,
V+,SCL, SDA and GND. Any help will be greatly appreciated.
abeza

floresta
Posts: 93
Joined: Mon Jul 28, 2008 6:52 pm
Location: Western New York, USA
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Re: TMP421 temperature sensor

Post by floresta » Fri Feb 18, 2011 1:01 pm

Maybe this will help:
Go to http://shop.moderndevice.com/products/t ... ure-sensor and click on the lower right photograph at the bottom of the page. This uses the V+,SCL, SDA and GND pins so I assume that the software provides for the V+ and GND at the appropriate pins. It looks like the other four pins are for external sensors - follow the links to the TI datasheet.

Don

abeza
Posts: 4
Joined: Fri Feb 18, 2011 12:32 pm

Re: TMP421 temperature sensor

Post by abeza » Fri Feb 18, 2011 2:14 pm

Thanks Don, for your quick reply.
When I looked at the picture in the past I did not notice the
header was visible. I'll solder the header as shown in the picture.
Again thanks for your help.

abeza

abeza
Posts: 4
Joined: Fri Feb 18, 2011 12:32 pm

Re: TMP421 temperature sensor

Post by abeza » Sat Feb 19, 2011 1:52 pm

Does anyone have a schematic diagram of the moderndevice TMP421 temperature sensor board.
I can't figure out where pin 1 is located on the sensor chip of the board, there usually is a dot
located on one of the corners of the chip, indicating pin 1. The chip on the pc board does not show
the dot. Thanks in advance for your help. I am trying to interface the sensor board to a Picaxe controller.

abeza

floresta
Posts: 93
Joined: Mon Jul 28, 2008 6:52 pm
Location: Western New York, USA
Contact:

Re: TMP421 temperature sensor

Post by floresta » Sat Feb 19, 2011 2:52 pm

It looks like you are not familiar with the pin layout on the Arduino board. In the photo mentioned in my previous post the TMP421 board is plugged into Arduino pins 2,3,4,5 with pin 5 being the one nearest to the 'corner' of the Arduino pc board. Now if you look at the "Arduino Pin Mapping' paragraph just above the photo you should be able to figure out that the four header pins are GND, Vin, Data, and Clock, left to right as viewed in that photo. This information is not guaranteed - it's the best I can do without having one of the boards myself.

Don

abeza
Posts: 4
Joined: Fri Feb 18, 2011 12:32 pm

Re: TMP421 temperature sensor

Post by abeza » Sun Feb 20, 2011 10:59 am

Thanks Don,

For you help again, through your assistance I figured out what I needed to know.
The TMP421 temperature sensor board by ModernDevices has a 10kohm pullup resistor going to
data (pin 6) and a 10kohm pullup resistor going to the clk (pins7) of the sensor chip. There also
is a capacitor connected to +v and ground. I now have all the chip pins and parts of the board identified.

abeza

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