Need many outputs

K

kakolon

Member
Hi, Im working on a project where I will have to turn on and off many lamps (180 lamps). What would be a way of achieving this?

Thanks in advance,

Regards,
Kakolon
 
T

terrapinlogo

Member
Shift Registers, multiplexing, charliplexing, i/o expanders. All possible ways but some may not be suitable depending on how you need to turn the lamps on.
 
hippy

hippy

Technical Support
Staff member
Depending on what the lamps are it could be best using a PICAXE to control just one or a few lights then build a lot of those.
 
E

elanman99

Senior Member
kakolon said:
Hi, Im working on a project where I will have to turn on and off many lamps (180 lamps). What would be a way of achieving this?

Thanks in advance,

Regards,
Kakolon
Click to expand...
What about the MM5486 IC?

Whilst this chip 'only' drives 33 outputs it is designed to be cascadeable. A company I worked for used these to drive 8 groups of 4 digit, seven segment LED displays (one MM5486 per 9999 disp so 8 lines with decimal point and one spare). Its got a shift register, latches and each output line can sink 15mA.

It was a few years ago but I recall that the chip was really easy to drive (I didn't do the software) but as its use is not limited to LEDs it could control say, 33 relays.

Ian
 
E

elanman99

Senior Member
elanman99 said:
What about the MM5486 IC?

Ian
Click to expand...
Bad form to reply to ones own post but I feel a chump!

Before suggesting the MM5486 I downloaded a datasheet (that's becoming more of a pain these days). The PDF sheet was created 1995 but their was no note saying 'not recommended for new designs' or somesuch, so I made the post.

I have just tried to find a supplier without success. National Semiconductor website does not even have one hit so I presume its dead. Bit like the Monty Python Parrot.

Sorry for wasting your time folks

Ian
 
W

westaust55

Moderator
Firstly we need to know what PICAXE chip you are using.

If it is an "M" series then shift registers would be the way to go with many cascaded togehter in a string using just 3 outputs to control.
Albeit a bit primative, the 75HC595 is a stalwart providing 8 outputs per chip with reasonable current capacity for the outputs.
However an M series chip only has 256 bytes of program space so not much room for control of 180 indications/lamps/LEDs

If it is an X/X1/X2 then consider an i2c based part. The MCP23017 16 IO (as two 8-bit ports) has been used by members here. Only need have as many chips as the '595 approach.

Then it is a cas eof what is the voltage and current rating of the "lamps". maybe you will need some interfcaes such as open collector Darlington transistor arrays if the voltage is greater than 5V or the current much more than around 10 to 15 mA.

More information will help folks here give you the best solution.
 
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