No I don't think so... There is no base bias on the second transistor (it should be a PNP) the first transistor is cut off when the emitter is high when it's low there is nothing at the  collector for it to work with. This is a conceptually bad adaptation of a ttl gate input.

Bob

Using the nomenclature from OP's circuit diagram: When the emitter of T2 is > 1.4V, T1 is biased into saturation through the 4k7 resistor and the forward biased PN junction of T2. When the emitter of T2 is low, T2 is saturated and its collector is lower than required to turn on T1 and the output is pulled up to 5V.

I don't really understand for what this first resistor is needed. Could someone explain me this? Would my solution work?

I think you mean "transistor" instead of "resistor". The answer to that question is that the second circuit can switch faster due to the potentially lower value of the base resistor, since the capacitance of the transistor junction would be able to charge and discharge faster. In practice, retrolefty's advice will no doubt work perfectly for your application. The second circuit is the classic input stage to a TTL integrated circuit and makes sense when you are building ICs because transistors and diodes take up less space on the die than resistors.

The micro USB is the most difficult of all the USB connectors to connect properly. I hate it. This will not only throw a little light on the problem but will provide a method of knowing the orientation of the connector without having to study the end.

One of my offspring got one of these for Christmas. Have any of you seen them? Made in the UK and pretty nifty.

http://www.mikromart.com

Actually I think a standard pot with or without detents could make a fine menu selection input device. Just wire the pot ends to ground and +5vdc and after reading a pot wiper value do a right shift of say 6 bits, so the resulting pot values would be 16 distinct values depending on pot position, that could be used to select 16 different menu items in the coding.

Lefty

That would certainly work. You would a have a constant position of the knob for each menu item which may or may not be desirable. It might make the software slightly more complicated for when you wanted to add/delete menu pages. Another way for sure.

50 cents, you're overpaying.
http://www.digikey.com/product-detail/en/ATS16B/CTX1085-ND/2640031
35 cents, with proper software can see as little as 1 second drift per day.

Give an example. You could calibrate out the +- 30ppm frequency deviation in software but how would you propose dealing with the +- 50ppm stability with temperature?

Yeah, I'm familiar with those kinds of hardware solutions but I was wondering how CrossRoads proposed doing it in software.
In ham radio equipment they often use a small adjustable variable trimmer cap in place of one of the fixed padding caps to fine tune the resonance frequency of the crystal +/- a few KHz, but that wouldn't have any improvement for the tempo stability variation of the crystal, that you live with or control the environmental temperature of the crystal.

Lefty

The technical name for which is "detents", although "dents" is sure to get you a laugh.

Yep dyslexia and an iPad are not friends 

I can sympathize. I get some pretty funny autocorrects from my iDevices. 

Well there are/were pots that had mechanical detents, used a lot is older stereo systems to give it a higher tech feel I guess.

Lefty

Agreed, but one wouldn't normally use one of those to select pages on an LCD like OP wants.

A pot with detents sounds like a really bad idea if the pot gets dirty at one of the detents. Probably why they use encoders for that application nowadays.

50 cents, you're overpaying.
http://www.digikey.com/product-detail/en/ATS16B/CTX1085-ND/2640031
35 cents, with proper software can see as little as 1 second drift per day.

Give an example. You could calibrate out the +- 30ppm frequency deviation in software but how would you propose dealing with the +- 50ppm stability with temperature?

What you're after is a called "rotary encoder"

Yes but you can get them with or without "dents" these dents are the click that you feel when you turn it. You can also get different number of dents per revolution.

The technical name for which is "detents", although "dents" is sure to get you a laugh.

The term potentiometer is incorrect in this situation, as a potentiometer is a type of variable resistor. As noted by others, a rotary encoder is what you are looking for.

Strangely enough, Siri got the proper spelling but didn't know what it meant.

I dont know what that means. If you like, I can search the web for 'Arduino'.

A web search brought up www.arduino.cc/ as the first choice.

i know the five inside should be connected like this. but i cant fit under my bed anymore.

Try sleeping on top and putting the batteries under the bed.

Please publish a link to the library.

Google "ip67 enclosure with transparent lid" and select Images. You might see something that you could work into your design. At least you'd be assured of a truly waterproof enclosure.

It looks like NHD calls the command 'DD RAM Address Set'.

If you want to put the cursor at address 0x40 then the seven-bit binary version of this address would be 100 0000.  

To convert this seven-bit address to a command (aka an instruction) you would put the address bits into DB6 <--> DB0 and then set DB7 to specify the 'DD RAM Address Set' command.

This means that your specific DD RAM Address Set command would be 1100 0000.

So you would send this value, which in hex is 0xC0 to the instruction register of the LCD controller.

[Edit] CAUTION:  Pin 2 is contrast and pin 3 is V_DD, reversed from just about every other LCD.

Don

That's definitely a big enough clue.