gitdyr / clackenrelay Goto Github PK

This little program is a controller for the $30 FT245RL USB relay boards you can pick up online. It was made to be fast, flexible and Just Works out of the box on Linux systems, without messing with permissions or kernel modules.

• libftdi
• gcc

gcc -Wall -Os -lftdi relay.c -o relay
strip relay

(todo: add makefile)

• No error handling or warnings (patches welcome)
• Doesn't support multiple boards (need to buy a 2nd)
• Untested on non-linux systems (probably won't work, patches welcome)
• Untested on 2 & 4 channel boards (probably will work on anything with a FT245RL)

Each relay is represented by a bit and all eight relays are a single byte combined. Individual relays can be opened, closed or toggled. There are several different schemes by which individual relays can be addressed.

Formats:

• -R (raw) The control byte is a literal character. The letter k would set the relays to 0x6B. Not too useful but very fun.
• -X (hex) The default format. Bytes are represented by strings such as 0x6B. Capitalization does not matter, leading 0x is optional.
• -D (decimal) Same as hex but in base 10. For example, 103.
• -I (integer) The byte is represented by several given bits where 0 is the LSB and 7 is the MSB. For example 01256. Order does not matter.
• -1 (one-indexed) Same as -I except LSB is 1 and MSB is 8, and people will tease you.

Commands:

• -c XX Close the relays in the given byte.
• -o XX Open the relays in the given byte.
• -s XX Set all relays. True means closed and false means open.
• -t XX Toggle the relays in the given byte.
• -r Read off the current state of the relays to stdout.

The format of the given/displayed byte argument is determined by the most recently set format option. Multiple commands and formats can be used in the same call.

Streaming:

Control input is normally taken from the command line arguments. So any change to the relays requires another call and initialization. For faster response and less overhead a single instance may be left open in "streaming" mode, where the program acts on commands from stdin. There are two streaming modes:

• -C Character-based. Immediately updates as a character is received. Only works with raw, integer and one-indexed formats. May work with hex on a four-channel board. IO format cannot be change in this mode.
• -L Line based. Updates on a newline. Uses the exact same syntax as the usual CLI argments.

Close relay 0 and 1, open all others:

relay -s 3

Open relay 6 and 7, close relay 0 and 1, toggle relay 3 and 5, (2 and 4 are left unchanged), read out final value:

relay -I -o 67 -c 01 -t 35 -r

Same, but using several formats:

relay -X -o 0xC0 -D -c 3 -R -t '(' -I -r

Create a simulated blinkenlight clackenrelay keyboard (type furiously, ^C to exit):

relay -t 0 -CR