There’s a lot of acronyms in the title for this article – what I wanted to say was “Adventures with surface-mount technology soldering with the Wayne & Layne Blinky Persistence-of-vision surface-mount technology reprogrammable light emitting diode kit…” No, seriously. Anyhow – after my last attempt at working with hand soldering surface-mount components couldn’t really be called a success, I was looking for something to start again with. After a little searching around I found the subject for today’s review and ordered it post-haste. Delivery from the US to Australia was twelve calendar days – which is pretty good, so you know the organisation is shipping quickly once you paid.
The kit is by “Wayne and Layne” which was founded by two computer engineering graduates. They have a range of open-source electronics kits that look like fun and a lot of “blinkyness”. Our POV kit is a simple persistence-of-vision display. By using eight LEDs in a row you can display words and basic characters by waving the thing through the air at speed, giving the illusion of a larger display. An analogy to this would be a dot-matrix printer that prints with ink which only lasts a fraction of a second. More on that later, first – putting it together.
Like most other kits it arrived in an anti-static bag, with a label clearly telling you where the instructions are:
Upon opening the amount of items included seemed a little light:
However the instructions are detailed:
… and upon opening, reveal the rest of the components:
… which are taped down to their matching description on the cardboard. When cutting the tape to access the parts, do it slowly otherwise you might send them flying off somewhere on the bench and spend ten minutes looking for it. Finally, the PCB in more detail:
After reviewing the instructions, it was time to fire up my trusty Hakko and get started. At this point a few tools will come in handy, including SMT tweezers, some solder wick and a piece of blu-tac:
Following the instructions, and taking your time are the key to success. When mounting the two-pad components – put a blob of solder on one pad, then use tweezers to move the component in whilst keeping that pad of solder molten, remove the iron, then let go with the tweezers. Then the results should resemble capacitor C1 on the board as shown below:
Then a quick blob at the other end seals it in. This was easily repeated for the resistors. The next step was the pre-programmed PIC microcontroller. It is in the form of a SOIC package type, and required some delicate work. The first step was to stick it down with some blu-tac:
… then solder down one pin at each end. Doing so holds it in place and you can remove the blu-tac and solder the rest of the pins in. I couldn’t solder each pin individually, so dragged solder across the pins then tried to soak up the excess with solder wick. I didn’t find this too successful, so instead used the solder sucker to mop up the excess:
If you solder, you should get one of these – they’re indispensable. Moving forward, the PIC finally sat well and looked OK:
Next was the power-switch. It clicks neatly into the PCB making soldering very easy. Then the LEDs. They’re tiny and some may find it difficult to identify the anode and cathode. If you look at the top, there is a tiny dot closer to one end – that end is the cathode. For example, in the lineup:
Soldering in the LEDs wasn’t too bad – however to save time do all the anodes first, then the cathodes:
At this point all the tricky work is over. There are the light-sensor LEDs and the reset button for the top:
And the coin-cell battery holder for the bottom. The battery is also included with the kit:
Once you’ve put the battery in, turn it on and wave it about in front of yourself. There are some pre-programmed messages and symbols already loaded, which you can change with the button. However you’ll want to put your own messages into the POV – and the process for doing so is very clever. Visit the programming page, and follow the instructions. Basically you enter the text into the form, set the POV to programming mode – and hold it up against two squares on your monitor. The website will then blink the data which is received by the light-sensitive LEDs. Once completed, the POV will inform you of success or failure. This method of programming is much simpler than having to flash the microcontroller every time – well done Wayne and Layne. A pin and connector is also included which allows you to wear the blinky as a badge. Maybe at a hackerspace, but not in public.
Once programmed some fun can be had trying out various speeds of waving the blinky. For example, here it is with the speed not fast enough at all:
… and a little bit faster:
And finally with me running past the camera:
Furthermore, there is an ‘easter egg’ in the software, which is shown below:
We had a lot of fun with this simple little kit, and learned a thing or two about hand-soldering SMT. It can be done with components that aren’t too small – however doing so was an interesting challenge and the results were quite fun. So it met our needs very well. Anyone can do it with some patience and a clean soldering iron. You can order the Blinky POV SMT kit directly from Wayne & Layne. Full-sized images available on flickr. This kit was purchased without notifying the supplier.
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