relay

Relay Board.

PIGMY Boards: Sold out 4-Apr-99

Mates with the PIGMY and PIPEX boards.

(Companies mentioned are Australian, however most common relays should fit this board).

This is my design for a Relay board that uses common PCB mount +5V or +12V Dick SMITH, Rod IRVING, TANDY, JAYCAR, ALTRONICS etc., relays. It supports 8 relays per board. There is a LED "ON" indicator for each relay and a Power LED on each board. Easy to get ULN2003 chips are used as the relay drivers. These have a drive current of 350ma per leg and will handle up to 50 Volts. The data section of Dick Smith's Cat. has info on this device. CAT. Z-5380

YES, I know about the ULN2803 8 bit driver, and have known for some time, however have found that it is harder to source. I design from garden variery components if possible.

hints.html provides pinouts and specifications of ULN2003 and ULN2803 Cathode drivers, plus UDN2983 Anode drivers.

The RELAY8 board measures approx. 5.5" by 2.75".

PIGMY Connection

Mates with J2 Header of my Pigmy board.

A Pigmy board can drive 16 relays using two RELAY8 boards. Port B of the PIC device is used for the first board, and port C for the second. If the PIC device is only an 18 pin device, then only 1 relay board can be used. You will find instructions for using one board only via port C of 28 pin devices if port B isn't suitable because of configuration conflicts.

PIPEX Connection

Header J1 mates with OUTPUT HEADER 1 of a PIPEX board.

Header J2 cascades to a second identical board of 8 relays. The same setup can be repeated with OUTPUT HEADER 2 of a PIPEX board. This means that four of these boards can be connected to one PIPEX board for a total of 32 relays.

34 wire flat ribbon cable and IDC type crimp connectors are used for board inter-connections.

Suits relays with up to 17mm by 33mm base dimensions. Multiple holes at .1" centres under the bases enable the installation of most common types of miniature and sub miniature relays. All coils will line up. Readily suitable for coils that have .1", .2", or .3" centres. Some output contacts may need to be jumpered. It will suit Reed and DIP packages also.

It has been specially designed for the cheapest relay I could find, which is the Dick Smith Cat P-8008. These are $2.95 each or $25.10 for 10.

One connection of this relay is down past the coil connections, so you will need to install 8 jumpers on the component side of the board. These can be seen on the above overlay. The coil centres at .475" are also catered for.

Output contacts appear on two sets of 12 way PCB mount screw terminals. I have designed the board so that it suits both 5mm and 5.08mm centres.

A value of 560 OHMS has been chosen for the nine LED resistors. This will suit both +5V and +12V supplies. The Cathode end of each LED is right next to its Resistor.

A 2 way PCB mount screw terminal is available to connect Ground and +12V to each board. This can connect to the +12V POWER-OUT of a Pigmy board if you choose to do it this way.

L1 is a link option to jumper +5V power from your Pigmy or PIPEX board if required. It is also handy when the board is used just as an LED monitor.

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