Who would think about using electronic device instead of real birthday cake. But who knows – there might be few nerds who would like such thing. Maksym thought it would be cool to create such device. It not only mimics birthday cake but also have piezo sensor which reacts to air flow. So it can be blow on to make it flicker and go out.
Circuit is built around Attiny44 microcontroller with 9 LEDs attached to it. Cake is made of two PCBs where one is dedicated to control circuit while another carries LEDs with sensor in the middle. There are many things that can be improved here. First of all it needs random LED flickering for better candle mimic. There probably would be great to have varying number of LEDs to match the birthday age. Probably different Charliepelxing algorithm could do the trick. Some nice 3D printed case wouldn’t hurt also.
For simple microcontroller prototyping there is no problem program chip from computer by using one of many programmer adapter. Setting thing up takes a bit of time, but for up to several chips this is not a big problem. But when your projects scale up a bit, flashing issue may become annoying. When you need to flash lots of them you start for more robust solution. The guys from Solderlab grew to the point where lots of AVRs need to be programmed so instead of doing this old fashion way they built an auto programmer.
Their auto programmer is capable of programming AVR microcontrollers automatically. All you need is to put hex file in to micro SD card and once powered it can flash chip automatically. Programmer can work with DIP AVR chips also program via ISP. It has a Nokia 5510 LCD where navigation menu is displayed. Here you can select what to do including: flashing, reading, reading fuses and other stuff. LCD also displays progress bar while programming and error messages if there are some. Same or more information it also outputs to UART where with terminal program you can control and monitor programming process. In order to program smoothly, hex files has to be prepared with addition header information from where programmer takes information about chip to be programmed, fuse settings, chips flash size and flash page size. Once set you can start piling chips pretty fast.
Numitron tubes are special type of displays, where digits are constructed out of segments like in 7-segment LED displays. They can be driven with standard 74HC595 shift registers. Numitron indicators require about 20mA of current so interfacing them to microcontrollers is fairly easy. Kalshagar have built really nice four Numitron digits based digital clock.
He wanted clock to be modular so that different parts could be reused in other projects if needed. To do so, he split design in to two boards – a display board which carries only tubes and driving circuit; while another part where microcontroller, RTC and backup battery is. He has done several versions of board and enclosure while eventually he stayed with rusty metal casing which looks really great.
When starting new microcontroller based project you start looking for suitable platform to start with. Many times in small projects Arduino takes over because it is popular, simple and have great ecosystem with tons of libraries and project examples. It is hard to beat this, but possible…
Pieter have sent us an update on their development board which runs on Atmega328p microcontroller. It doesn’t follow Arduinoe standards, but rather focus on other things that make easier development and testing. Their scorpion development board have all necessary elements like efficient power regulator, USB-USART bridge, buzzer, 512K dataflash, LED, push button, ADC scale and filtering. The rest of connection interfaces and GPIO are positioned on the side of PCB.
But this is not a board what makes it great. They’ve done great work on building software framework to develop embedded programs clean and efficiently. Firmware library has been developed to be portable between 8-bit, 16-bit and 32-bit systems. Framework focuses on good developing practices that evolved during years of coding. Several great project examples will get you started in no time and in time you will start appreciate the hard work they’ve put in.