So I had some issues when putting the final product into use. Which is to be expected, but this bugger had me opening the case at least 6 seperate times..
Issue 1 : when the 5v relays would kick in, it my 7805 voltage regulators didn’t have the reserver to engage them both at the same time. I needed to add a capacitor. I did it the easy way, and just screwed it into the terminals. The +5v is wired in parallel so both relays benefit.
Issue 2 : I used digital pins 0 and 1 on the arduino to control the relays. Turns out those pins are used for serial communications. So when updating the board the relays woudl clickclickclickclick like no tomorrow. No good, had to use different pins. Obviously I didn’t account for that on the board creation, so they got solder to the pins directly. Picture is a little out of focus, but it is the orange/yellow leads in the foreground.
Issue 3 : In the external power strip where 6 seperate relays live and are controlled by the arduino here, I made a mistake in that I didn’t have any 10k pull-down resistors on the 6 control lines. I should have put them in my original circuit, and instead I added them via a little ‘daughter’ board I added to my original circuit board. Oh, and if you actually jump to read about the external power strip know I took the power supply and arduino out as they are replaced by this build. All that is left is the transistors and relays.
Ribbon cable removed, and ‘riser’ pins installed:
Daughter board freshly machined:
Lessions Learned :
* Patience. I had to keep telling myself that there was no way I would get everything right on the first try.
* That a 7805 regulator needs a headsink in most cases.
* That a 7805 also needs filter capacitors. You can’t just plop it in a circuit and expect clean output.