[Michael]

Are you saying that you are wiring the batteries to the connector in parallel? That won’t give you 9V.

You need to wire the batteries in series, because you need 6 x 1.5V = 9V. That is, wire the holders so that the batteries are in effect “end to end”.

Example:

red wire of 4 cell holder to plug connector red
black wire of 4 cell holder to red wire of first 1 cell holder
black wire of first 1 cell holder to red wire of second 1 cell holder
black wire of second 1 cell holder to plug connector black

See how all the batteries are now chained together end to end. That’s how you get the voltages to add up to 9V.

[Michael]

Just a follow up note for anyone following this thread: the original problem reported by boxseuss was caused by a short circuit on the board due to a large amount of solder on a pin. The problem was on the 10K resistor near the bottom left of the board. The purpose of this resistor is to provide a 5V signal (and limit the current) to pin 1 of the ATmega microcontroller. Pin 1 is the reset line which needs to be held HIGH. When it goes LOW, the microcontroller resets.

The short circuit caused this reset line to be LOW at all times, so the microcontroller was constantly being reset and would not run.

So if your clock displays 0000 and the colon is not lit or blinking, then the microcontroller is not running at all. Check VCC, GND and reset pins on the ATmega as a first step.

[Michael]

Technically, yes, you can use 12V input, but the voltage regulator will get a fairly warm. Give it a try, and if you can still touch the regulator after 10 minutes, then it’s no problem. Otherwise, you can provide 9V with six C or D cell batteries.

[Michael]

Thanks, it sounds like you’ve done everything right. I suggest that you reflow the solder joints on the chips. There have been many times when a good joint is in fact not. I’ve had customers return devices claiming the joints were all good, and they aren’t. I’m sure you are good at soldering, but this would be the next thing to check.

Also, does anything happen when you press the DET button or ALARM+DET?

Of course I’ll make this all right for you by providing a replacement device asap, but am wondering if you can do just a bit more diagnosis in case it’s just a bad connection.

[Michael]

Andy,
That’s odd. The 1-2 second delay to power on is normal, but 0000 is not. Can you please check these things and provide some more info:

1) are all your chips oriented properly? Ensure that the notches are in the right positions. The 74HC595 chip is supposed to have the notch on the right and that makes the text on the chip upside down.
2) Have you checked your solder joints? If any look suspect you can reflow them by touching them with a soldering iron.
3) Is the ATmega chip seated securely in the socket?
4) Can you tell me the details of your power supply? 9V, but how many mA can it provide?
5) Is the voltage regulator hot? Like, too hot to touch?
6) Do you have an FTDI cable for programming (if so, you could reprogram the chip using Arduino IDE)?
7) Got a multimeter?
8) You aren’t laying the device on a conductive surface and shorting it out, right?
9) Are you certain you soldered the two large capacitors near the power jack with the right polarity?

Any info you can give is useful. I have not received the other customer’s unit that is behaving the same way, but I find it odd that two customers have experienced the same problem.

[Michael]

Try adjusting the line

tv.delay(2);

to a lower value. That should speed it up!

[Michael]

Use PAL. SECAM and PAL use identical timings. The differences between PAL and SECAM are in how color is represented, which doesn’t matter for the Video Experimenter.

[Michael]

Yes, I believe it will work with SECAM. The LM1881 sync separator claims to work with SECAM. See http://nootropicdesign.com/ve/downloads/LM1881.pdf

I have many customers in France and have not received any complaints.

[Michael]

themanontheinside,

I think you should power it with 6 D cell batteries. That will provide 9V (6 x 1.5V) and should last a long time. I think C cell batteries would work, too. Let us know what you discover.

I can’t wait to see what you build. Email pics to info@nootropicdesign.com or michael@nootropicdesign.com, or post here and I’ll add to the gallery.

When you press the red DET button, you can increase the countdown time by pressing the hour and min buttons before releasing the DET button. I added this feature specifically for the Airsoft community. Countdown can be as high as 99 minutes, 59 seconds.

[Michael]

Bizarre. Something is very wrong. I will send you an assembled/tested unit (I found your customer record based on your email address) and will also include a return postage label so that you can send back the defective unit. I need to investigate what is wrong, as I have not seen this problem before.

Sorry about the inconvenience, and thanks for your patience.

[Michael]

I don’t think 100mA is enough to power it. The device is drawing too much current, probably 150mA during normal operation. I didn’t even know that there were adapters that only provided 100mA and I will update my instructions to be clear about current requirements.

A 9V battery isn’t going to deliver enough, either.

Do you have access to something that can deliver at least 250mA? I sell adapters in my store, and will gladly give you free shipping.

Sorry about not being clear about the current requirements.

[Michael]

Ok, thanks for that info. If the colon was blinking every second, then we’d know that the chip was simply not programmed with the clock software and was running the default “blink” Arduino sketch.

If the chip is running the clock software, the colon should be lit. The colon is connected to Arduino ouput pin 13, and it is simply set to HIGH to always keep the colon on.

How long is the delay between powerup and display? I’d expect about 1 second.
Can you tell about the power supply you are using? Is it 9V center positive? How many mA can it deliver?

If we can’t solve this, I’ll certainly replace the product.

[Michael]

I’m sorry to hear that. Have you checked that all chips are oriented correctly? How about solder connections?

A display of 0000 could indicate that the chip is not programmed, but I do test each one. Is the colon lit? Is it blinking?

[Michael]

You should be able to hack this device however you want, especially if you change the software. If you have a USB to serial adapter cable or breakout board, then you can program it with Arduino. The code is available on the Hack page : http://nootropicdesign.com/defusableclock/hack.html

Agree that using a relay is the right way to trigger a 12V siren.

Glad you guys are thinking about hacks and mods already!

[Michael]

Awesome — I can’t wait to see what you build. I’ll put it on the gallery page:
http://nootropicdesign.com/defusableclock/gallery.html

[Author]

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