sms2blinken A SMS To Blinkenlights Gateway In Hardware
The sms2blinken project is a device which receives text messages from a
GSM modem and sends them to a Blinkenlights which is connected by
Ethernet. The device does all the decoding and streaming of the single
frames which hold a part of the message.
To ensure a maximum of compatibility the original Blinkenlights
protocol (BLP)
is used to send the data to the Blinkenlights. This
protocol is based on simple UDP packets containing the data for one
frame which is to be displayed by the Blinkenlights.
There is a simple 5x7 pixel font included(I honestly don't know where i
did get it. If you can tell me so I'd like to credit the author).
As GSM modem a M20 Terminal from Siemens is used which i got from a
friend who got it from eBay. A more common mobile phone like the S25 or
S35 should work too as the software uses the PDU mode of the
modem/phone to read the text messages. (In case of the M20 you'd have
to
make sure that the handshake lines of the RS232 interface are correctly
wired so the modem accepts incoming data.)
The hardware is based on an Atmel ATMega16 microcontroller with 16kB
program memory. About 13kB of it is used by the code, so there should
be some room for your extensions. Most of it is used by the integrated
TCP/UDP/IP stack (which is uip 0.9). With
some effort you could remove
the TCP parts of it as only UDP is used.
Sadly I couldn't find the schematics of the hardware anymore as its
original use was a a RS232<->Ethernet gateway. But as the modem
also speaks RS232 it was a perfect fit for the application.
The pin configuration for the Ethernet chip is contained in rtl8019.h.
Please note that PD3 and PD4 are used to drive some leds.
If you want do rebuild this circuit you might want to not use the old
RTL8019 anymore but the newer and more elegant Ethernet chip ENC28J60
from Microchip. This would require some changes to the device driver of
uip, but there are already projects which have done this(see
http://avr.auctionant.de/avrETH1/index.html).
Here is a picture of the device connected to the M20 GSM modem and an
Ethernet enabled Blinkenled:
The more or less undocumented(...) code:
blinken2sms-0.1.tar.gz