I spend this rainy day working on an old project and I am happy to announce its 99.8% finished. Now I have a nice Atmel Board screwed to the wall with an ethernet port. Nice little project where you can access measurement values and digital I/Os via normal http access. For now I have 3 temperature sensors running. One outside, one on the ceiling and one on the floor of my office. Idea is to control a fan when the temperature between the ceiling and the floor is to hight. I have this problem specially in winter times when the heater is on. Next week I will attach a light sensor as well. For now you can find all the measurements on pachube feed 1303. For example here is the outside temperature sensor. Time is in utc.
If you ever wondered if geeks are social here is the answer. Yes they are and they are very social and organising some very cool events which are called “geekends”. Combination of weekend and geek. Not just going for hiking with friends. No developing, building, ironing and coding very cool and geeky things.
As being a reader of the very cool MAKE magazin I read the article on a brain machine the other day. This project is great for a geekend. Something to build, some hardware, software and after all a great toy to play with.
The idea is to build one of these Brainwave (aka Light and Sound Machines) on your own with a little micro controller. Lets see if we can optimize the hard and software a little bit. The original one is based on an other project and therefore the hard and software is not optimizes for a LSM.
More Information on the original project you can find the the blog here.
Stay tuned to my blog to read more on this geekend.
Moin
After a lot of experiments with Atmel and servos the schematic design for the leg controller is ready. Unfortunately the Atmega8 has the I2C interface on 2 of the ACDs so only 4 ACDs are left. Therefore I have to use 1 Atmega8 for each leg to control the 3 servos. Besides the PWM servo control I also added 3 PWM LED controllers (via transistor). Just in case later on I decide to “pimp my robot” Well at least I can use them for visual debugging when I train the robot to walk. The idea of this schematic is quite easy. There are
2 connectors for the bus (i2c and power)
3 connectors for LEDs (transistor connected)
3 PWM servo connectors (with current (resistor) measurement)
1 SPI interface to flash the atmel onboard
Well its not a big deal but maybe someone finds it usefull. Next week I have to fight with placing it on a board without to many crossings.
While searching for PWM for my atmel I found this video. If you want to see a robot dancing to WMCA and”Walk Like an Egyptian” have a look at the video.
Today I found a lot of time working on my Atmel project. My colleague Angel pointed me to the AVR USB lib project (link). Really great and makes the use of USB as easy as the good old RS232. In fact I found it even easier to deal now with USB then RS232. And hey you get 5V for free.
I started with the PowerSwitch project. Nice little USB interface to control 8 digital outputs (for switching on or off whatever you like). Its a nice Project to get started with the lib.
For programming the Atmel I used my USBProg programmer from Embedded Project. With the SPI its really great to plash the Atmel inside your circuit. Be aware that the Pins are a little bit different than in the description. In order to flash the code to my atmega8 I used avrdude:
avrdude -c avrispv2 -P usb -p atmega8 -B8 -U flash:w:main.hex:i
The B8 parameter is very important otherwise the Atmega8 is not recognized. When you use the Atmega8 instead of the micro controller mentioned in the documentation you have to take care to use the right pins on the Atmel (it costs me 1 hour of searching for a wire error before I thought of that. )
The changes for the ISP Connector are:
Pin 10 from the ISP connection is not connected as described to TXD instead its connected to PIN 8 and 22 as beeing the GND.
Pin 4,6 and 8 from the ISP connection are not connected at all
Now I have a nice Atmel Board screwed to the wall with an ethernet port. Nice little project where you can access measurement values and digital I/Os via normal http access. For now I have 3 temperature sensors running. One outside, one on the ceiling and one on the floor of my office. Idea is to control a fan when the temperature between the ceiling and the floor is to hight. I have this problem specially in winter times when the heater is on. Next week I will attach a light sensor as well. For now you can find all the measurements on pachube feed 1303. For example here is the outside temperature sensor. Time is in utc. 
