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Hey Tony, I saw on the shop page that you offer a special edition of the 5 tube clock using IN-8-2 tubes. Can these tubes be used in place of the IN-14 tubes without any modification to the board? If so, what is the specific part for the symbol tube?

It's not quite that easy, to make the tubes fit I'd originally intended just to swap 2 tracks on the PCB but ended up making a small batch of redesigned boards, the software also needs slightly modifying to alter the digit order.
It can be done using the old board and software, either by wiring the IN-8-2 tubes with the cathodes routed 1:1 to the IN14 cathodes or cutting/rerouting tracks on the PCB. I will post the IN-8-2 version of the software soon if you want to try it the easier way.

The symbol tube is still an IN-19 as it's the only one available in any quantity that's suitable.

Tony, sorry if this is a foolish question but do you have any particular preference for GPS modules what aren't excessively spendy and work well with the clock? I can roll the dice, but since I've ordered two of the kits from ThinkGeek, one of which is a going away present for a friend who's leaving the country, I'd prefer to get a couple of the right ones from the get-go. I'd _prefer_ something with an actual housing, but a bare module is fine too at a pinch.

Cheers

Dermot Conner.

The modules I've used were just surplus PDA GPS upgrade units which I modified (added a serial and power cable) and worked at 4800bps.
If there had been demand I'd considered suppying ready to use receivers in a matching case but from the replies I've had you're probably the third to use one. I wonder if it would still be worth making a few up.

Excellent. I'm thinking pretty much any of the standard 9600baud serial UART GPS modules kicking around should do the trick;
http://www.amazon.com/s/ref=nb_sb_noss? ... l+uart+gps

Stuff one of those into the smallest project box I can find and sucker it to a window and Robert's your mother's proverbial.

Hi Tony,
If I want to Replace C2 with a non-rechargeable lithium cell and holder are there any wiring changed I need to make?
Cheers

Yes, it will need a diode to prevent reverse charging.

On the underside of the PCB there are 2 rectangular solder tabs, one of which is used as a ground point for the crystal capacitors. Those were intended for a CR2032 holder but in the end they weren't used. Just below C2 is a space for D20 - not fitted - which would have been the protection diode for the 2032.

You'll need to fit a low voltage drop diode there and connect the cell's + terminal to its anode.

This should have been the first post on this thread but has been deleted by mistake -


GPS input - 5V TTL level serial data at 2400/4800/9600 BPS (auto detect). Wire up a jack plug for SK2 as follows:

Tip - Ground
Centre barrel - 5V
Outer barrel - Data out from GPS.

Fit wire links in places R14 (upper) and R27 (R34 for V2 PCBs) when building the PCB if you intend to use this in future.


Louder/quieter alarm: Reduce or increase the value of R12, acceptable values are from about 27R to 220R+


Brighter LEDs: Reduce to value of R6,7,17,19,22 to a min. of 470R. To remove the LED feature just bridge D2-6 with solder.