Hi I'm looking for a way to switch an external 24v with the 5v Arduino output I currently have sort of working with a transistor but id need multiple and I'm out of board space anyone know of a relay arrangement/module I could use that will work reliably and doesn't take up much space thanks.
If you don't have space for a transistor, you won't have space for anything else.
You need more space.
How much current needs to be switched? This is just as important as the voltage, when answering your question.
Modules/chips that can switch higher voltage and currents than an Arduino output include
ULN2003 (old, not ideal)
ULN2803 (old, not ideal)
TPIC6B595
TPIC6A595
TPIC6595
and others.
But each has it's limitations and may not be suitable for your project.
Hi sorry my question wasn't really detailed enough but I need to switch multiple separate channels (6) independently. I have space in general just not on the board I have that's why I was hoping for something I could mount independently.
Hi thanks ill check the current and have a look at the data sheets and see if any of the chips will work, I might be able to squeeze one in with some rearranging.
Those are Darlington transistor arrays, which are used for switching higher currents ULN2003 500mA.
You could of course make your own Darlington pair out a couple of NPN transistors, or buy individual Darlington transistors if you just need to place them close to the switching device.
Take care that you read and understand the data sheets correctly. For example, the ULN chips are rated for 500mA per channel, but not for all channels at 500mA at the same time. But for the TPIC chips, they might be rated for only 150mA per channel, but that's 150mA per channel for all channels at the same time. So how many channels you need to be active at the same time might guide your choice.
Another factor which may be important is voltage drop. The old ULN chips will probably drop 1.5~2V of the input voltage. At 24V this might not be much of an issue, but at 5V it certainly can be an issue. This voltage drop is because they use Darlingtons.
The newer TPIC chips use MOSFETs instead of Darlingtons, so their voltage drop is only a few tens of millivolts, making them much more useful at lower voltages like 5V.
Basic questions: Is it AC or DC? How much Current? What is the load? Also post your schematic so we can help you get more room.
High-side or low-side switching?
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