The tools required to build a BlipBox from a kit are likely to be found in every electronic hobbyist toolbox.
- Good quality soldering iron
- Tip tinner (recommended)
- Flux pen or similar (recommended)
- Solder wick (highly recommended)
- Wet sponge!
Your most important tool is a decent iron. I use an Antex 25W (£16.99 from Maplins in the UK), which is very basic but works just great.
In addition you are likely to need some tools to build or modify an enclosure for your creation.
Assembly of the BlipBox kit includes one surface mount part: a 6 way FFC (flat flex cable) connector. If you have never soldered SMT before then this is a good one to start with, as it has a relatively large 1mm pitch. If you have never soldered anything before then you should probably try something easier first.
Note that the BlipBox main board does not include MIDI, power or USB connections. For USB, you can use an FTDI integrated USB-UART cable, TTL-232R. This will also power the device over USB.
If you are planning to take your BlipBox on the road then you may want to skip as many sockets you can and dare. Note that if you solder the LED matrices straight to the PCB you will no longer be able to access the component side of the board. Keep this in mind!
Start with the surface mount connector. I wouldn’t attempt this myself without having some flux and solder braid / solda mop handy.
Apply a bit of flux on the PCB pads.
Make a little dome of solder on one of the larger pads by heating the pad up and letting the solder melt against it.
Place the connector in the correct position with the pins aligned to the pads, then heat up the dome of solder momentarily to fix it in place. Hold it in place for an extra second while the solder solidifies to avoid pulling it away with your finger!
If the legs are not well aligned, melt the solder joint and try to move the connector in place with your fingers, tweezer or suitable pliers.
Now solder the opposite side to ensure it is held firmly in place. With the connector secured and properly aligned the most difficult bit is done, now only the tiny pads in the center remain to be soldered.
If you don’t have a very small tip you can do several pins at once. Don’t worry if you get solder in between or across legs, instead ensure that all pads are properly connected.
Remove any excess solder from the legs with solder wick. Remember to remove the wick while heating it with the iron so that it doesn’t stick to the pads!
Check the connections with a multimeter. Use JP3 to check for shorts (remember pin 6 is not used/connected). Check continuity by opening the connector and probing the pins there, or use the exposed connections on the top of the housing.
Alright, so that’s the hardest bit done!
Next solder the resistors R1 and R2. R1 is soldered across the footprint of the trimpot, as in the picture (todo). It can be replaced by a 5k or 2k5 trimpot if desired.
R3 is only used for mods.
Solder the IC sockets, make sure you put them in with the notch facing the same way as in the footprint.
Next up is the right angle 6 way header (if you are planning to use an FTDI USB cable), followed up capacitors C1-C4. Keep the legs as short as possible. With C4, make sure you respect the polarity. Negative is indicated with a – sign on white background on one side of the cap, and positive is indicated with a small dot on the PCB (negative goes to the right).
If you have a tall capacitor, more than 10mm or so, then you will probably want to place it at a right angle; fold it forwards so that it lies flat on its side against the circuit board. This is to ensure that the LED modules can fit snugly on the board. After the capacitors, solder the discrete transistors.
Next do the 2×3 way ICSP header. Point the right angle header outwards.
Solder the 4 female headers used to connect the LED modules. Only every other pin is used (square pads), the others do not have to be soldered. Try to solder them straight and not get them at funny angles.
Solder the ZTT resonantor any way you want as long as the middle leg goes in the middle.
It’s always a good idea to solder the smallest components first, so that when you turn the component side down it pushes the part that you want to solder into place.
Snip the legs of resistors and capacitors after you’ve soldered them.
Visually check solder joints by holding the board up to a strong light and see if it shines through the PCB holes.
Use lead free solder and non toxic rosin. It’s good for you, it’s good for everyone.
Make sure the bare ends of the ffc cable face down and the cable is oriented to the top of the pcb, so that the first 5 connections are made between the 5-way cable and the 6-way connector.
Insert IC1 and IC2.
Connect LED modules and touchscreen.
The LED module orientation is not important, the notches can go either way, just ensure they both go the same way so that they slot together.
Burn Bootloader and Set Fuses
The ATMega chip needs a small program to run on startup which allows you to upload software via a USB connection: the Bootloader. We’re going to use the Arduino bootloader, which also lets you upload and run Arduino sketches on the BlipBox.
If you have not ordered a kit with a bootloader pre-loaded, then you will have to burn it yourself.
- avrdude binary (comes with the Arduino environment which you should have installed)
- bootloader HEX file (e.g. hardware/bootloaders/atmega168/ATmegaBOOT_168_diecimila.hex in the Arduino installation)
- ISP programmer (e.g. AVRUSB500 from TuxGraphic or USBTinyISP from Ladyada.net)
Install the Arduino environment and locate the avrdude binary.
Connect a programmer to the BlipBox ICSP header.
Check that everything is connected correctly:
$ avrdude -c avrusb500 -p m168 -v
avrdude: Device signature = 0x1e9406
avrdude: safemode: lfuse reads as FF
avrdude: safemode: hfuse reads as DD
avrdude: safemode: efuse reads as 0
avrdude done. Thank you.
$ avrdude -c avrusb500 -p m168 -U lfuse:w:0xff:m -U hfuse:w:0xdd:m -U efuse:w:0×00:m
$avrdude -c avrusb500 -p m168 -U flash:w:arduino/hardware/bootloaders/atmega168/ATmegaBOOT_168_diecimila.hex
avrdude: 16294 bytes of flash verified
avrdude: safemode: Fuses OK
avrdude done. Thank you.