Please note, this is an ‘open collector’ driver – it can only be used to connect the load to ground and there will be a 1 Volt (or more) ‘drop’ across the internal transistors. The inputs can be driven by 3.3V or 5V logic. Fits nicely in any breadboard or perfboard.
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Is this avalible in a shield for an arduino? Put this in line with an 8 wide DIP switches (or maybe a 16 or 13 pin – so it can be selectivly interfaced with any arduino pin, at some risk of a person flipping the wrong switches) so that it can be disconnected on certain pins and it instantly becomes compatible with almost any arduino shield. Days like this I wish I had a PCB mill…
@andrew, not yet – but stay tuned!
@Andrew, I put a uln2803 on a protoshield together with a mcp23008 and a couple of connection terminals. I use it to drive relays. Works great and saves a lot of Pins!
BTW, I’ve been wondering if you can turn something like this into an H-bridge by adding just a simple resistor and PNP transistor to the high-side. http://www.flickr.com/photos/[email protected]/7847799300/
This has potential frugality advantages since low-side drivers are pretty common and cheap, and pnp transistors are cheap, but high-side drivers or full h-bridges are rarer and dearer.
The demands on the PNP transistor (for gain/etc) are pretty low, since the ULN can provide a lot of base current, and does the voltage conversion…