wiki/ Lv2LaunchTowerRelay

LV2 Launch Tower Relay (LTR) Board

Launch Tower Relay (LTR) board as of August 4th, 2005

Overview: This board has a PIC18F458 (running PicCore) which runs four relays in the launch tower electronics box and interfaces to the LTC via the CAN bus. It also has some analog ports available for thermistors, and a lot of expansion room for daughterboards and whatnot.

Hardware Notes.

Attached below are the Schematic and board layout, in EAGLE CAD and PDF.

Relay 1 LATD0 Ignition relay
Relay 2 LATD1 Shore power relay
Relay 3 LATD2 Strobe relay
Relay 4 LATD3 Siren relay

We didn't end up using any of the thermistor ports, but we really should in order to keep track of the temperature in the box (don't want stuff frying in there).

Firmware Notes

Firmware for the node can be found at:

Before any relays can be turned on, you need to arm the board via a CAN message; see the readme file in the firmware directory for CAN message IDs.

Project Notes

Date Notes
08/04/2005 Replaced ignition relay with a new SPST relay... and fixed burned out (!!!) trace. Cut traces which would have shorted out new SPST contacts. Moved LEDs to a high efficiency, clear LEDs with plastic tubes around them for better viewing. Used a 10k pulldown on PIC sense of old SPDT relay.
03/24/2004 Posted page. Posted schematics. Ver 0 vs Ver 1? As below, we'll call 1.0 the first board run.
08/14/2003 Version 1.0: WARNING, PCB HAS ERRORS. The DRC wasn't checked because of the number of misc. inconsequential problems: some traces actually touch and thus are shorted on the board. Also, the ICD2 connector has somehow - astoundingly - been mirrored. See the readme.txt file.