AVR LCD Namebadge

So, you're going to a conference/meetup/nerdfest and you want to do something that sets you apart from normal people.  An LCD namebadge powered by an ATtiny2313 is a great way to do that.  This is a general purpose LCD display unit powered by a 9V battery and a simple voltage regulator circuit (the same 7805 circuit you see absolutely everywhere).  It's no-frills, but it can be etched, drilled and soldered in 1-3 hours by an experienced hobbyist, and 3-6 by a beginner/intermediate one.  It all depends on how many issues you encounter along the way, and how well-equipped you are to fix them.

I found this great instructable that shows how to breadboard this same circuit, and this is based on it.

This is my first project that I've taken from breadboard to schematic to protoboard to functioning PCB, so I'm going to try and document some of the pain I went through along the way, as well as some things that helped, in hopes that your first end-to-end electronics design is a little easier.

Step 1 Supplies

Tools

• Decently-sized Breadboard (I used an 840-hole)
• Breadboard hookup wires (I prefer stiff hookups for on-board work and longer flexible ones for ISP hookup and long runs)
• Multimeter with conductivity testing mode (beep!) and DC voltage mode
• Soldering iron - I have a 50-watt that I love.
• An etching vessel - see PCB etching instructables.
• A drill and PCB drill bits (I used sizes 65 and 75).  A mini drill press helps too.
• A hot glue gun (optional, but barely - the wire broke twice on me with very little force applied)
• An AVR ISP programmer (I built a USBTinyISP)
• Helping hands (optional)

Components

• An ATtiny2313 (or 2313A, which is what I used - functionally equivalent)
• An HD44780 LCD with a single row of pins
• A 20-pin DIP socket
• A 7805 Voltage Regulator (you can definitely get away with a low-amperage one too, I just had these laying around)
• A 100uF capacitor
• A 10uF capacitor
• A 330-ohm resistor
• A 10K-ohm resistor
• A 1N4004 diode (other diodes will probably work fine too - make sure to read the datasheet though)
• A 5K linear potentiometer (or between a 1.5K and 2.5K resistor if you don't care about contrast adjustment - YMMV)
• A 9V wired connector - preferably one that doesn't suck (I have suck ones.)
• Breakable male header strip - you'll need 16 pins, but these usually come as 40-pin strips.

Materials

• Etchant - again, see etching instructables
• Solder, preferably very thin stuff.  I'm using .015 diameter.
• PCB, single sided, whatever color you see fit.
• Hot glue sticks - awwww yeah

Comments

[robot head]

hi i am not able to programm my attiny2313 as i am not able to compile the c code so can som 1 compile it an mail the hex file to me at my email [e-mail]

[jgosselin]

i built this but a bit differently i designed it so the PCB was no larger than the LCD
and left out the potentiometer using your suggested resistor values. and it looks awesome so small. i put longer leads on the battery so i can sit in my pocket. and BAM its a fun little gadget people stare at all the time.

[hardwarehank]

Awesome! I'd love to see your board layout. If you could post a brd file, that would be very helpful! Glad you like the result.

[hightekrednek2396]

nice
whered you get the plans for the programmer

5 stars

[hardwarehank]

I built the one here:

http://www.ladyada.net/make/usbtinyisp/

Thanks!

[bertus52x11]

I like this!
(you could add sensors too!)

[hardwarehank]

That's a great idea :). Maybe in the Mark II... we'll see how motivated I get. Thanks for the feedback!