Custom built Arduino is not working - double blinks

Question

I've made a home-made Arduino based on this video. The problem is that I can't upload anything, it doesn't react, only the LED double blinks in every second. What does that mean? How to fix it? Thanks.

Update: photo

• Nick Gammon: This is surely impossible to answer without seeing what you did. Presumably you did something different from what is in the video, what that is, is impossible to say. I suggest posting a very clear photograph, at the very least.
• haxpanel: Thanks for the quick reply - I've just provided one. Hope that helps. Thanks :)
• brtiberio: Did you bought atmega chip with bootloader already on it?
• haxpanel: I guess so - at least according to the Ebay seller.

Answer 1

It's a reasonably clear photo (another couple would help) however I do see at least one major problem. Pin 8 (and pin 22) are Ground, but I don't see any wires running to that. Also the 22 pF (or similar) capacitors connected to the crystal should have their other sides grounded.

I suggest you look at my page Breadboard Arduino which has clear photos and wiring guides. In particular:

Minimal Arduino

Notice the ground wire, and how the capacitors are connected.

I suggest you double-check all wiring, and make sure it is very similar to this:

Atmega328P wiring

• haxpanel: I've just checked it but the 22s are already grounded to pin 8 as that is a ground. I updated that area anyway according to your photo but having the same issue. I've built this entire stuff for 3 times but getting the same result. :(
• Nick Gammon: Yes, but pin 8 should have a ground wire. You shouldn't rely on it being grounded through the chip. Also the capacitor in series with reset looks a lot larger than 0.1 µF.
• haxpanel: Ohh I see, mine is a 100uF one. I mixed up with the 100nF. The smallest I have now is a 1uF. I wish I could just quickly "download" one ...
• Nick Gammon: 3D printer? And a bit of aluminium foil? Just remove the wire leading to the capacitor. When the upload starts briefly ground it to reset the processor (a quick tap) and then un-ground it.
• haxpanel: I haven't got any 3D printer but an oven and a hair dryer. Am I still good?