This is my first project with a true microcontroller (I’ve done embedded projects with phones, gumstix, routers, etc, but never this low level).
I’ve got an antenna rotor I’d like to control. It takes 0V thru 5V to control direction. The rotor will be connected to some sort of controller, then to a linksys wireless router running linux via RS-232 connection. The idea is the wireless router can move the antenna rotor through the microcontroller to adjust for best signal.
Ok, basically since this is my first microcontroller project, I need to know what hardware I’ll need. Here’s what I’ve thought of so far…
ATMEGA32
AVR-P40 prototyping board
AVR-PG1 programmer
I was thinking maybe a motor controller of some sort would be able to send voltages? This is the last part that is perplexing me. What last piece of hardware would I need to actually send voltages to the antenna rotor?
I’m a little confussed on what it takes to controll the direction of the antenna.
Do you want to change the voltage going to the antenna or do you want to move the antenna with a servo?
If you need to change the output voltage you might check out stuff like the
MAX5550 which is a digital to analog converter that is controlled through i2c (which means if you are running on a gumstix, you don’t need another processor)
If you just want to controll direction with a servo I’d check out Dave Hylands’ robostix branch. This should port right over to the Atmega32 if you have enough code space and if you are using a 16mhrz crystal on the ATmega32.
jessewelling:
I’m a little confussed on what it takes to controll the direction of the antenna.
Do you want to change the voltage going to the antenna or do you want to move the antenna with a servo?
If you need to change the output voltage you might check out stuff like the
MAX5550 which is a digital to analog converter that is controlled through i2c (which means if you are running on a gumstix, you don’t need another processor)
If you just want to controll direction with a servo I’d check out Dave Hylands’ robostix branch. This should port right over to the Atmega32 if you have enough code space and if you are using a 16mhrz crystal on the ATmega32.
Hope this helps!
The documentation of the antenna rotor says it takes variable voltage for direction. i.e. 5V would send it all right, 2.5V would send it center, etc, etc. Normally servos use PWM at a constant voltage, right? I was a little confused by this too. It looks like I’m going to need digital to analog conversion so I’ll look at the maxim DAC.
I won’t actually be using the gumstix on this project, I was just referencing it as the style embedded programming I’ve done in the past. I’ll actually be using a linksys router with the openwrt firmware.
The idea is to be able to control the antenna rotor from the wireless router so it can automatically adjust for best signal. I could probably hook the router straight to the MAX5550, but I’d rather the AVR be an abtraction layer in between the two.
I think I actually saw an article when googling the other day with the MAX5550 and AVR, so I’ll see if I can find that again and that’ll probably be the route I take.