Dangerous Prototypes Open Source Hardware

New Twatch Assembly

June 25, 2010, 03:28:02 am

I just got my Twatch. I ordered the version without the LCD attached to the PCB. I’m somewhat new to this stuff; this will actually be my first soldering project. I really want to learn. So I just want to make sure that I’m set, and that I’m assembling it properly.

Just from looking at the LCD and the PCB, I’ve noticed that I’ve got sixteen pins and sixteen pinholes so I’m assuming that those are what I need to solder? Is there anything else that I need to do beside that?

Also I know that I need to pickup a cover for the jumpers and an AC Adapter, aside from that does anyone have any tips?

Re: New Twatch Assembly

Reply #1 – June 25, 2010, 08:46:44 am

Hi enculturation - Good luck on your first soldering project. The 16 pins are soldered into the 16 holes on the LCD. The power socket and network connector should be on the outside (not facing the LCD).

I'm not sure what you mean by cover for the jumpers.

A 7-10volt DC power supply (AC adapter) will work. The #twatch has a 2.1mm DC barrel jack connector, it's supposed to be the most common type (according to wikipedia). It uses the standard connection type where the outside of the connector is ground, and the center pin is the supply voltage.

Please let me know if you have any questions during your build or if you need any more help. Enjoy the #twatch, and have fun soldering

Re: New Twatch Assembly

Reply #2 – June 26, 2010, 04:51:52 pm

Hi Ian thanks for the reply! I've just got another really basic question. Should I bend the ends of the pins to create joints for soldering? Or is there another technique I should use?

Re: New Twatch Assembly

Reply #3 – June 26, 2010, 04:58:37 pm

Hum, I'm not sure what you mean. I usually use straight pin header. I solder it to the PCB, then slip the LCD over the pins and solder the pins to the LCD.

Re: New Twatch Assembly

Reply #4 – June 26, 2010, 10:39:37 pm

I just meant should I bend the pins on the PCB after sliding the LCD on to form joints for soldering? This picture may help: http://www.instructables.com/image/F8QNF5Q0DIEWP8729Q/How-to-Solder.jpg The pins are angled. When you say straight pin header do you mean you're using a header beyond what was included in the kit? Sorry for all the basic questions.

Re: New Twatch Assembly

Reply #5 – June 26, 2010, 10:56:33 pm

[quote author="enculturation"]Should I bend the ends of the pins to create joints for soldering? Or is there another technique I should use?[/quote]Typically, you would only bend the leads on passive parts like resistors and capacitors.  Personally, I would not bend the pins on an LCD.

And to be clear, bending the pins doesn't create anything for soldering - it really just holds the part tight so that you don't make a cold soldering by moving the part while soldering.  For something like an LCD, I'd just find another way to hold the part in place, then solder pins on the corner first to act as a holder while you solder the remaining pins.

Caveat: I've not built this particular project, and I haven't worked with these particular parts, so there may be some specific techniques that I'm not thinking of.

Re: New Twatch Assembly

Reply #6 – June 26, 2010, 11:06:48 pm

When soldering header you don't need to bend all the pins, mostly none!

Place the header and hold the header on the 'cold' side (the opposit where you start to solder) with your hand, then solder just one pin. Keep it heating (without melting the plastic) until it is firmly in place. Let it cool and check if it is still correctly in place. Solder the pin at the other end. If happy solder the remaining pins.

Basicly just try to do it and find your own comfortable way

Re: New Twatch Assembly

Reply #7 – June 27, 2010, 08:13:57 am

I attached two pictures of headers, one is straight, the other 90 degrees. Did you maybe get a 90 degree header with the LCD?

Here's a picture of Seeed's assembled #twatch with LCD:
http://www.seeedstudio.com/depot/twatch ... Path=61_68

Re: New Twatch Assembly

Reply #8 – June 28, 2010, 10:06:04 pm

Thanks again guys. No the headers that came attached are straight. I think I've got it now. I'll let you know how it goes once I get a chance to sit down and do it.