New Open Source Hardware board in stock BB-ADS1262 ten channel low noise, low power 32-bit sigma-delta ADC

BB-ADS1262

BB-ADS1262 is breakboard for ADS1262 low-noise, low-drift 38.4-kSPS, delta-sigma (ΔΣ) ADCs with an integrated  PGA, reference, and internal fault monitors.

Possible applications are sensor reading, small signals (ECG/EEG),  weigh scales, strain-gauge sensors, thermocouples, and resistance temperature devices (RTD).

 

Measuring temperatures from -250C to +1600C with AVR-T32U4 Arduino Leonardo and MOD-TC-MK2-31885 + thermocouple

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MOD-TC-MK2-31885 is UEXT module which uses MAX31885 and allow temperatures in range -250C to +1600C to be measured with proper thermocouple.

For this demo we use TC-K-TYPE which is low cost K-type thermocouple.

When the thermocouple is connected pay attention that it have polarity i.e. if your measurements start to decrease when you increase the thermocouple end temperature you have to swap the thermocouple wires to the connector.

Another issue we got with Arduino 1.0.4 is that Serial print from time to time stop working on Leonardo and several uploads usually solve the problem, we guess this is some USB port problem and Leonardo is not properly enumerated as CDC serial port every time.

Also I2C library on Leonardo sometimes beahve weird and in this case you have to decrease I2C speed a bit. So if the sketch do not work correctly just edit TWI_FREQ to 80000L in:

C:\arduino-1.0.4\libraries\Wire\utility\twi.h

#ifndef TWI_FREQ
 #define TWI_FREQ 100000L
 #endif

You can watch the demo at this video: http://www.youtube.com/watch?v=ltS5ZEJiCEM

As you can see there are two temperatures which are measured: the temperature on the thermocouple TC and the internal MAX31855 temperature INT (i.e. cold end thermocouple temperature).

Also MAX31885 recognize if the thermocouple is disconnected, shorted or connected to VCC.

The demo code is at GitHub: https://github.com/OLIMEX/DUINO/tree/master/AVR/MOD-TC-MK2-31885

FRIDAY FREE BOARD QUIZ ISSUE #13 PRIZE IS MOD-TC-MK2-31855

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MOD-TC-MK2-31855 is UEXT Module whth the new MAX31855 IC and works with K-Type thermocouple and measure temperature from -200C to +1350C with 0.25 C resolution.

MOD-TC-MK2-31855 works with I2C and this allow many MOD-TC-MK2-31855 to be connected together to any of our boards with UEXT connector.

MOD-TC-MK2-31855 have also 7 general purpose GPIOs which also can be read and written with I2C commands.
Everyone have chance to win this board if answer correctly our Quiz question.

Today at 17.00 o’clock our local Bulgarian time (GMT+3) we will post on Twitter our question.

You have one hour to reply to our tweet with the correct answer.

At 18.00 o’clock we will count the correct answers and ask random.org to generate random number in range then anнounce the winner and ship the board by airmail next Monday.

Good luck!

DuinoMite: Measurement of High Temperatures with K-type Thermocouple

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Thermocouples are one of the most widely used temperature sensors in the industrial application.

The reason they are so popular is that they are low cost to manufacture, reliable and work in extremly high temperature range.

More info on the thermocouples you can read on http://en.wikipedia.org/wiki/Thermocouple

In this application we will measure the temperature with K-type thermocouple which works with temperatures from –180C to +1100C.

These K-types thermocouples are the same which are used in the soldering irons for the temperature control of the soldering tips, they are used also in the reflow ovens, reflow profiles etc.

Some low cost multimeter also have K-type thermocouples to measure temperature, we will take our exactly from such multimeter.

The thermocouples produce very low voltage in the range on micro Volts, and preciese amplifier is necessary to amplify the result to something measurable with microcontroller.

Fortunately for us Maxim-Dallas have MAX6675 thermocouple interface IC which have not only amplifier but also Analog-to-Digital converter and cold junction compensation, so with this IC you can read the temperature directly with SPI.

Our UEXT connector have SPI interface so it was logically to produce MOD-TC which connects to UEXT and interface to Thermocouples.

The DuinoMite code which reads the temperature with MOD-TC is only 10 lines:

10 SCK=10:MISO=9:MOSI=8:CS=19 ‘define where SPI interface is (UEXT connector)
20 SETPIN SCK,8:SETPIN MOSI,8:SETPIN MISO,2:SETPIN CS,8 ‘set all ports are Digital outputs except MISO which is input
30 PIN(CS) = 0 ‘pull CS low to enable the MAX6675
40 PAUSE 100 ‘wait 100ms to settle the chip (not really necessary)
50 B1 = SPI(MISO,MOSI,SCK,0) ‘read high part of the 16 bit result
60 B2 = SPI(MISO,MOSI,SCK,0) ‘read low part of the 16 bit result
70 PIN(CS) = 1 ‘disable MAX6675
80 PRINT “temperature is: “;(B2+B1*256)/32;”C” ‘display the temperature
90 PAUSE 300 ‘wait a bit to not scroll too fast the results
100 GOTO 30 ‘do it forever

Here is the result first with program run at ambient temperature:

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Then I decided to measure the temperature at the upper end of cigare lighter flame, soon the tip of the thermocouple become red and the result was:

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wow I didn’t knew the cigare lighter flame is as hot as 900C!