What thermostat can be interface to Serial port?

[marcasjr™]

gusto po kac gumawa program gamit ang VB which displays temperature.

[7_SeVeN_7]

ds1621... bitbang mo na lang yung I2C using handshaking pins ng serial port...

[marcasjr™]

May nakita po akong lm35,output nya voltage proportional to the temp.
Pano po ba mag measure voltage in serial port sa VB?
tnx for any reply....

[rdpzycho]

kung LM35 gagamitin mo kailangan mo ng MCU na kukuha nung voltage niya tapos convert using ADC then output using UART...

[7_SeVeN_7]

eto di ko pa natatry pero check mo kung feasible..

research ka ng ADC na parallel ang output. tapos research ka din ng parallel to serial shift register. tapos gamitin mo yung dtr at rts handshaking for pulses like clock.

[rdpzycho]

74HC165 - Parallel to Serial...pero 3 pins ata kailangan...1 clock 1 data 1 latch...baka merong 2 pins lang...

ginagawa ko sa pushbutton yan...pero hindi sa 232...

feasible...

[zer0w1ng]

Another trick is to use the parallel port and add an R2R ladder as DAC. Then with one comparator, put the A/D input on one input and the DAC output on the other. Then starting from 0, change the DAC value using MSB bits first and perform a "binary search".  Use the comparator output to determine when the voltage output of the DAC is similar the A/D input (when the LSB can toggle it).  The last resulting R2R DAC setting is the A/D reading.