![]() ![]() The LEDs around the edge (60 of them) are connected as an 8×8 matrix with the last set having just four LEDs (LED56-LED59). So how is this “magic” achieved? As it turns out, quite an elaborate multiplexing scheme is in use. ![]() This board has a lot of LEDs to drive, and yet, uses a 40-pin chip just like the other kit. There’s quite a few blocks in the code, and the flow is a bit haphazard, but that’s what’s there. I’m no expert in code disassembly, but I did load it into IDA Pro just to see that it wasn’t just random data. I suppose this might mean that there really isn’t much space remaining for more code. The dump of the program seems to show that the code has the EC1204B model number in it, and occupies about 7015 bytes of the 8192 bytes available. However, I will make a few quick notes.Īs with the other kit, the chip doesn’t appear to have any code protection lock on it, so it could be reprogrammed and updated. Quick Reverse EngineeringĪs this kit seems at least a little popular, I didn’t feel the need to fully reverse engineer the board and draw a schematic. By using this construction manual, and a table listing components, I could eventually work out which components went where.Īs it turns out, there are quite a few modifications made by others, which include even replacing the microcontroller with another so other features could be more easily added. As it turns out, this seems to be a clone of the EC1204/EC1204B kit with only minor changes. I contacted the seller, but they didn’t respond in the day, so I decided to do a little digging through similar kits. The kit had two different resistor values and two different capacitor values without any clear way to differentiate which is mounted where. As the silkscreen did not have the component values, I was slightly stuck. Uh Oh! Where’s the Docs?Īt this point, it’s obvious that no documentation had been provided with the kit. It, like the other LED based kit, is a test of endurance as well with a large number of through-hole components needing to be mounted carefully. It also means that you need to have a set of fine tweezers and a fine tipped iron, in addition to supplying your own solder, side-cutters, soldering iron and desoldering braid. This makes the kit a medium-to-high level difficulty kit, rather unsuitable for absolute beginners. What sets this kit apart from others is that there is a non-negligible amount of SMD components that need to be mounted. Of course, it is missing a CR2032 battery for the RTC, which is probably for cost reduction and shipping liability reasons. It is seen that IC-sockets and a simple mini-USB cable are provided, which is a nice touch. This is pretty regular for these kits, but isn’t strictly best practice. While the exterior used a static shielding bag, the components are bagged inside regular resealable bags, and the chips are placed into foam without foil shorting the pins. It appears to be just a 5v TTL-UART connection with Vcc and GND. There seems to be a provision for Bluetooth connection to a module, but this was not included in this kit. The word “speaker” is misspelt on the silkscreen. The board features component mounting on both sides. The rear of the board has the same finish, which is actually not bad. No identifying names are printed on the board, it seems. This arrangement allows for using the outer holes as mounting, or for removing the edges to have a circular clock face. It is roughly square in shape, with a circular inner, and rounded edges. The PCB is a blue-solder-mask double-sided tin-plated board with silkscreening indicating component placement. ![]() As a result, this would impact the construction process and the practicality of the final product slightly. Unfortunately, as the PCB was one of the larger elements inside, and the edges were designed to snap off, damage in shipping resulted in one corner being almost completely snapped off. This kit comes in a heat-sealed static-shielding bag. Imagine my surprise when it arrived today – the same day the US election results was to be announced? Instead of just being just a clock, it would be the doomsdayclock! The Package That’s what I thought, almost a month ago when I ordered it. For AU$8.06, it only cost more AU$2.50 more than the RTC chip alone from a local source, so it’s definitely good value. In this case, it was a clock based around the AT89S52 80C51 microcontroller and a DS1302 real-time clock. Since I started along the line of garish LED-adorned kits, I thought I’d order a few other kits built around the AT89S52. ![]()
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