Outstanding steampunkish VFD wristwatch

Wristwatch projects are coll for many reasons. First of all how they are built – components need to be squeezed to make watch wearable. Another thing is display. What different types of displays can be used. LCDs and LEDs seems to be getting boring, unless they are used in some weird way. Other things also are important like overall look, power supply , features and controls. Johnengineer has been working on steampunk wristwatch for couple months and he came up with something awesome. The unique idea was to use IVL2-7/5 VFD display. They are relatively small to fit on a watch and pulls out relatively small amount of current. It also requires low grid voltage (~12V). Display is transparent, so background PCB is visible and this can be considered a cool design feature. Clock is ticking around Atmega88 microcontroller along with RTC DS3231. Display is driven by dedicated MAX6920 12-bit shift register. Since watch is powered from single AA battery, there are couple boost converters – one for generating 5V to power electronics and another 13.5V to power VFD grid.… Continue reading

Motorbike gear indicator

Would you like to know what gear is currently on your motorbike? Then you should build a gear indicator. Following indicator has been built for Suzuki V-Storm that have real gear position sensor – it is up to read this information and display in convenient way like dot matrix LED display. Additionally indicator reads temperature from DS18B20 sensor and displays it in Fahrenheit and Celsius scale. Device has more available configurations you may find interesting. So it can be fun addition for your metal horse. Continue reading

Z80 machine emulator on AVR

Emulator is software that runs on some CPU and emulates another CPU or MCU so you could run programs and games without need of right one. There are lots of emulators for PC including PC emulators itself like Virtual PC or VMWare. But let’s leave them behind as they are more professional stuff. Let’s look at more lightweight stuff here. Sprite_tm has decided to emulate an old good Z80 on AVR ATMega88 microcontroller. To be more specific to be able running software there has to be CP/M machine emulated. AVR microcontroller is pretty low on RAM (1K for ATMega88) for such task so he used an external DRAM chip (GM71C4256A 128KB). CP/M used floppy discs but instead there is a MMC/SD card used. And last thing is display. For this simple UART terminal is used as there is only character based data only. Hardware is easy – firmware is another part that met many road blocks, but hey its working, not 100% accurate but working. Continue reading