Introduction Description
Construction Testing
User
Manual
Note: this project has been discontinued.
Note: TEMP08 no longer supports RELAY05 with current versions of software.
Build a Relay Interface for the TEMP08: the RELAY05
Introduction
The RELAY05 is an adjunct kit, originally designed
for use with the Midon Design TEMP05 and TEMP08 modules. With both units connected up
to your PC, 8 relays can be controlled via the PC's serial interface. Of
course, the TEMP05/08 unit is not required to operate the relays. Any TTL-level
signals can be connected to the RELAY05 U1 connector to activate the
relays. The unit operates from 12VDC at about 700mA with all relays
activated.
The relays used in this project are rated to 10A at 30VDC or 12A at 250VAC.
Figure 1. RELAY05
Description
Figure 2 RELAY05 Schematic Diagram
As you can see from Figure 2, this is a fairly simple
"step and repeat" circuit, utilizing the same basic relay drive
circuit for the 8 relays. The transistors, Q1-8, drive the relays from the
control signals presented at the inputs from U1. Diodes D1-8 are used to
prevent EMF back-surge from the relay de-activation from harming the
transistors. The same transistor drives the LED's through current-limiting
resistors R1-8. The relay outputs are brought out via terminal strips
J1-8.
The "D" version PCB also includes space
for installing a terminal strip, full-wave bridge and capacitor for independent
powering, should that be required.
Construction
Standard construction techniques may be used for this circuit and a printed circuit board is available if desired.
If building the RELAY05 from the PCB, refer to Figure 3 for component placement. Begin by inserting
an IC socket for U1. This will be used to inter-connect with the TEMP05
module. Follow this with the insertion of all passive components. Follow
this by inserting the LED's, diodes, and transistors. Insert the relays
and terminal strips last.
There is only 1 type of discrete resistor; 1.0K. The color codes for it
are shown in Table 1.
Insert the resistors where shown in Figure 3. The DIP resistor, R9, should be
mounted as shown, with care to ensure pin 1 is oriented to the square pad on the
PCB. Alternatively, discrete 10K ohm resistors could be used in it's
place. Use the alternate pads beside R9 should you choose to mount
individual resistors.
|
Resistor Color Codes |
|
Value |
1st Stripe |
2nd Stripe |
3rd Stripe |
4th Stripe (Tolerance) |
|
1.0K |
Brown |
Black |
Red |
Gold |
Table 1. Resistor Color Codes
Figure 3 Parts Placement
You are now ready to prove in the circuit.
Testing the Circuit
If you are using this kit in conjunction with the TEMP05 module, connect the
RELAY05 module up to the TEMP05 via a 16 pin DIP to DIP ribbon cable (not
available from Midon Design). Using the serial interface from your PC to
the TEMP05, issue a RLYx ON command (x = 1 to 8). The corresponding relay
and LED should activate. Do this for all relays to ensure that your
soldering and component insertion was OK. Trouble-shoot as required.
Ordering a Kit
This project is no longer available for ordering.
Parts List and Suggested Sources
Table 4. Included Parts List
|
Qty |
Designations |
Part Number |
Description |
JameCo Part # |
Other Source Part # |
|
8 |
DS1-DS8 |
LED |
LED, Red |
152856 |
|
|
8 |
D1-D8 |
1N4148 |
Diode, silicon |
36038 |
|
|
8 |
J1-J8 |
6-Term |
Terminal Strip, 6 position |
3 x 152346 or 2x 152354 |
|
|
8 |
K1-K8 |
Relay DPDT |
12V Relay, DPDT |
|
Tyco P&B RTE24012F |
|
8 |
Q1-Q8 |
2N2222A |
Transistor, NPN |
38236 |
|
|
8 |
R1-R8 |
1K |
Resistor, 1K 1/4W |
29663 |
|
|
1 |
R9 |
10KDIP |
DIP Resistor pack, 16 pin |
108628 |
|
|
1 |
U1 |
16PIN |
DIP Socket, 16 Pin |
37372 |
|
|
