New Product in stock: Temperature sensor SNS-TMP10K


SNS-TMP10K is low cost preciese temperature sensor with NTC thermistor. It have 10K +-1% resistance by 25C and the resistance decreases with the temperature rise i.e. it have negative temperature coefficient.

SNS-TMP10K is encapsulated in metal can with dimensions 25 x 5 mm and comes with 60 cm cable with JST 2 mm connector crimped to the wires.

The temperature coefficient B for this thermistor is 3435 and it’s very easy to measure the temperature with Arduino.

SNS-TMP10K is good for measuring temperatures in range -30+110C, as it’s encapsulated and filled with epoxy resin it’s good both to measure air and fluids like water etc.


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


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:


#ifndef TWI_FREQ
 #define TWI_FREQ 100000L

You can watch the demo at this video:

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:

STELLARIS-UEXT adapter for Stellaris launch pad in stock


STELLARIS-UEXT is Texas Instruments Stellaris Launchpad to UEXT adapter.

We have prepared demo code for MOD-GSM, MOD-MP3, MOD-GPS, MOD-TC, MOD-SMB380, MOD-IRDA, MOD-LCD3310 so you can interface these modules from your Stellaris Launchpad.

As Stellaris MCU have two SPI, I2C and UARTs we made the adapter with two separate UEXT connectors so you can connect two independant UEXT modules to it. Each UEXT have power up/down control with MOSFET so you can power up and down UEXT modules connected.

iMX233-OLinuXino-MAXI measure temperatures -200C to +700C with 0.25 resolution


MOD-TC-MK2-31855 allow tempearture measurement with high precission in range -200+700C.

As this board interface UEXT connector via I2C many such modules and thermocouples can be attached to one UEXT.

This GitHub project allow iMX233-OLinuXino-MAXI to measure temperature with MOD-TC-MK2 and K-type thermocouple.



OLIMEXINO-STM32 is Arduino like board based, which works with MAPLE IDE.

Three new demo examples are uploaded on OLIMEXINO-STM32 web page:

1. Measuring temperature with K-type thermocouple and MOD-TC

2. Lot-Of-Leds (LOL) shield demo example – looke at this video what LOL is:, we have 3mm 5mm 10mm and SMT LED LOL shields and the PTH come in DIY kit form or completely assembled.

have fun 🙂

DuinoMite Project: Interfacing Real Time Clock DS1307 and Interfacing BMP85 temperature / pressure


Mathias Johansson just posted two new projects made with DuinoMite on KSD forum:

DS1307 RTC interfacing and BMP085 temperature and pressure sensor interfacing


Today I decided to try another schematic for measurement of the temperature this time with LM335Z low cost sensor.

LM335Z have 0V at absolute zero temperature i.e. -273.2C and it’s output increase with 10mV/C so at room temperature the sensor will output about 2.73V

to measure this temperature with Duinomite is piece of cake:

10 SETPIN 1,1  ‘setup PIN(1) as analog input


the problem is that PIC32 Analog input can’t take more than 3.3V on it’s ADC, so maximal temperature measured will be 57C well this still is enough for some application, but why not measure the complete temperature range -40C+100C ? (if you use LM135 the range will be -55+150C)

to do this we have to add resistor ladder which to divide the output voltage, TassyJim uses 18K/27K in his project posted at TheBackShed forum, and I found his 0.6 round divider as nice so decided to use same values.

the schematic if used for industrial applications should have some protection diodes and resistors like on this picture:


but for the experiment I just used R1, R2, R3 and wired them to DuinoMite-Mini with jumper cables:


then  I wrote this simple code:

10 SETPIN 1,1

20 PRINT “ROOM TEMPERATURE IS: “; PIN(1)*166.7-273



it’s really not so hot in my office so I start thining what is wrong and I found it – I used 5% resistors as I had no preciese resistors so the voltage divider was not exactly 0.6 but something else and was mixing my result, no problem I took preciese ohm meter and measured R2 and R3 the values are:

R2 = 17 860 ohm

R3 = 26 600 ohm

aha so the voltage divider is 0.59829! and the coefficient I have to use in the formula is 100/0.59829 = 167.1

I corrected the formula:

20 PRINT “ROOM TEMPERATURE IS: “; PIN(1)*167.1-273



so with not preciese resistors I got preciese result because DM-BASIC have no problems to work multiply real numbers

so the complete code to measure temperature in -40C+100C with LM335Z fits in one line


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