USB powered thermometer and hygrometer

Name: USB powered thermometer and hygrometer
SKU: 2760
Price: 20.00 USD
Availability: OutOfStock
Rating: 4.75 (1 reviews)

(1 Review)

Designed by tomlab in Croatia

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$20.00

Out of Stock

Sold out since Nov 10, 2019

USB powered thermometer and hygrometer

This is actually the second revision of my USB thermometer (the first one is not listed on Tindie, there is a couple of words about it on my web page The main thought for this revision was to add humidity measurement so instead of using Maxim's DS18B20 temperature sensor I decided to use a cheap relative humidity sensor DHT22 which also has a temperature sensor. I drew a new board in Eagle based on the same Seedstudio's template for DP8049 acrylic case. The device is based on PIC16F88 running with internal oscilator and MAX7219 driver for 7 segment display. Firmware switches between temperauture and humidity display every 10 sec. If you wish to change the firmware, there is a place for ICSP connector, reset button, and a few of the IO pins are available. Initially I planned to put the sensor on the board (top right corner, and to span over the edge of the board) but in that position temperature readings were about two degrees higher so I decided to put it on the separate board. Power is supplied over the mini USB connector but there are also a few power pins on the board available. In this revision I also added acrylic "legs" so the device can stand on the table (well, it should be standing...)
The device is available for purchase in four colours: white, blue, yellow and red. The power supply adapter is not included.

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Review Breakdown

Average Ratings

Product: (5.00)

Documentation: (4.00)

Shipping: (5.00)

Communication: (5.00)

Mauro | Nov. 18, 2014

A little review

I received the product with very good speed, considering the well-known Italian postal delays.
I tested the thermo hygrometer with the supplied cable connecting the sensor dht22 a few inches and it worked immediately.
I then tested the connection with a telephone cable, 4-pin to 20 meters and the signal was absent, I discovered that the problem was caused by the poor quality of the 5-volt transformer that I've used, by connecting the mini usb to usb plug of my pc has taken all work perfectly.

I am passionate about meteorology and I already have semi-professional equipment, therefore I installed the sensor dht22 outside in my garden, in a screen davis as required by the WMO standards.

The sensor is on test from this morning and I can say it works very well, the differences with respect to the equipment in my possession (Davis Vantage Pro, DS18B20, data logger with probe PT100) are a tenth of a degree and 1% for humidity .

The thermo hygrometer is very well done, the communication was and still is very good and nice, I hope that one day we'll study an advanced version with resolution to the penny and storage of minimum and maximum values.

http://i.imgur.com/O6t7bGh.jpg

Thank you and I apologize to everyone for my bad English

$20.00