Résultats de recherche : attiny85

Déc 242014

In a previous article, I have use an attiny85 + ds18b20 + rf433 to built a cheap temperature probe.

This time, I needed the humidity next to the temperature.
I then decided to use a dht11 (you can get it starting at 1.50€ on ebay).
Total cost is below 4€.

Here below the wiring.


Here rf433_sendOOK_at85_dht11 the arduino sketch (rename the txt file to ino).
You will also need this dht11 library.

Here some pictures. Notice that i used an old (but still good for my purpose) smartphone 3.7v battery.




Oct 182014

In a previous article, we had use an Arduino + RF433 chip + DS28B20 to come up with a cheap temperature sensor.

We are going to improve the setup by replacing the Arduino Pro mini by an ATTINY85.
See here on how to flash an ATTINY85.

See rf433_sendOOK_at85 for the code.

Note that power consumption will be as low as 0.005ma (5ua) with a peak at 18ma when reading temp.

See below a revised wiring replacing the Arduino by an ATTINY85.



 Posted by at 17 h 42 min
Oct 182014

In previous article, I made a cheap temperature probe using an arduino pro mini.

Still, the arduino pro mini is a bit overkill and i would like to keep it for prototyping my projects, not on « live » projects.

So lets have a look at the attiny85 :
-it is cheap (1€ a piece)
-runs at 8mhz
-has 8k programmable memory
-has very low power consumption

Sounds perfect for my needs !

Lets have a look at the pinout.


To flash this baby, I decided to use my arduino uno r3.
See below a quick how to.

1- unzip attiny under Documents\Arduino\hardware (you should end up with a folder attiny in there)
2- start the arduino ide and upload the arduinoisp sketch (in the arduino examples) to your « arduino uno r3 » board
3- choose « arduino as isp » under tools\programmer menu
4- choose « attiny85 (8mhz) » under tools\board
5- upload your sketch onto the attiny85

Lets see how to wire our attiny85 to your arduino.


In a next article, we will see how to adapt this article for attiny85.

Hint : if you are getting the error « relocation truncated to fit », have a look here (and see to replace your ld.exe).

 Posted by at 13 h 46 min
Mar 032015

These days it is pretty easy to setup a Home Theater PC using a cheap computer (raspberry being my preferred choice).

Still, the remote control is many times the weak point.
It is easy to buy or refurbish an infrared remote transmitter, it is less easy/cheap to find an infrared receiver.
Thus, you can find some cheap telco+receiver like these :

I then thought it would be fun/interesting to use an arduino for this.

Quickly googling, I found 2 ways to achieve this :
-turn my arduino into a HID device (probably the cleanest way but more complex) thru the use of the v-usb firmware
-have the arduino send (over serial) the expected datas to LIRC (less complex but more prone to errors)

Lets do some mad googling and collect some interesting pointers

-setup LIRC and a FDTI232 adapter : here
-the arduino IRRemote lib as you will need to decode the incoming signals : here
-some arduino code which seems to turn the arduino into a lirc receiver : here
-another possible interesting thread : here
-a similar project with interesting links especially around irman protocol : here
-similar project using IRMAN protocol : here
-related, on attiny85 : here

-v-usb track : here

Oct 062014

My little project this last week end.

I need to add a few rf433 oregon temperature sensors to be linked to my rfxcom + jeedom domotic box.
Unfortunately, these sensors (oregon THGR122N) are about 25€ (or 15€ using a cresta clone), not including shiping costs.

Therefore I decided to do a cheap one myself using :
-an arduino pro mini (2.50€)
-a fs1000a transmitter (1.50€)
-a ds18b20 (1€)

The whole thing uses less than 2ma when sleeping, and max 20ma when it reads temperature from the ds18b20.

Here comes the sketch rf433_sendOOK.
Note that that I am re using code from connectingstuff.net to send oregon 2.1 compatible packets.

Possible evolution would be to replace the arduino pro mini by an ATTINY85.


Here comes the wiring.


 Posted by at 22 h 21 min