Arduino Hourglass Timer

thingiverse

A while ago I purchased one of those $3 Hourglass Shape Flashing LED DIY Kits from eBay. While it is a nice kit to build, it really has no practical purpose other than to show off its animation of an hour glass. It is not designed as a timer. I wanted to make mine into something useful yet keep the animation. I created a custom board that contains an Arduino, two mercury switches to detect the hourglass orientation, a rotary encoder to set the time from 1 to 99 minutes and a piezo electric speaker. I used the PCB that came in the kit to hold the LEDs. The STC15W201S microcontroller is replaced with a 16 pin ribbon cable that connects to my custom Arduino board. See "Hourglass Shape Flashing LED DIY Kits" https://www.instructables.com/id/Hourglass-Shape-Flashing-LED-DIY-Kits/ Video --------- https://youtu.be/0LKmR9BtNaw Parts ------- 1x Hourglass Shape Flashing LED DIY Kit 1x ATMega328 1x 28pin IC Socket 1x 16pin IC Socket 2x 16pin IC Plugs 1x 50mm 16 way Ribbon Cable 5x 10K 1/8W resistors 5x 0.1uf Monolithic Ceramic Capacitors (5mm hole spacing) 2x 22pf Disc Ceramic Capacitors 1x 10uF 16V electrolytic capacitor 1x 8Mhz HC-49S Crystal 1x EC11 Rotary encoder with switch 2x Glass 5mm Mercury Switch Angle Tilt Switch 1x Universal Passive Buzzer AC / 2KHz 3V 5V 12V 2x M3x5+6mm Male-Female spacers 2x 6mm M3 screws 1x 3.7V 400mAh LIPO battery 1x Mini Rocker Switch app 10x15mm 1x JST XH 2.5-2 Pin Battery Connector Plug Female & Male Programming ------------- The ATMega328 runs a 8Mhz crystal on a 3.7V supply. I used my home-made Arduno UNO board to program the ATMega328 chip. This board has a ZIF socket for the ATMega328 and allows me to change the crystal, supply voltage and program the chip via a USBTinyISP board or a FTDI board. Create a new entry in the Boards.txt file for a 8Mhz Arduino UNO. (%USERPROFILE%\AppData\Local\Arduino15\packages\arduino\hardware\avr\1.8.1\boards.txt) ############################################################## uno8.name=Arduino Uno (8Mhz) uno8.vid.0=0x2341 uno8.pid.0=0x0043 uno8.vid.1=0x2341 uno8.pid.1=0x0001 uno8.vid.2=0x2A03 uno8.pid.2=0x0043 uno8.vid.3=0x2341 uno8.pid.3=0x0243 uno8.upload.tool=avrdude uno8.upload.protocol=arduino uno8.upload.maximum_size=32256 uno8.upload.maximum_data_size=2048 uno8.upload.speed=57600 uno8.bootloader.tool=avrdude uno8.bootloader.extended_fuses=0xFE uno8.bootloader.unlock_bits=0x3F uno8.bootloader.lock_bits=0x0F uno8.bootloader.file=optiboot/optiboot_atmega328.hex uno8.build.mcu=atmega328p uno8.build.f_cpu=8000000L uno8.build.board=AVR_UNO_8 uno8.build.core=arduino uno8.build.variant=standard ############################################################## In the Arduino IDE 1. Select "Tools - Board - Arduino Uno (8Mhz)" 2. Select "Tools - Programmer - USBtinyISP" 3. Plug in your USBtinyISP to the ATMega328 (should be running a 8Mhz crystal) 4. Select "Tools - Burn bootloader" 5. Load up the sketch in the IDE 6. Select "Sketch - Upload using programmer" 7. Remove the ATMega328 from your development environment and place it on the PCB I found that the EEPROM on the ATMega328 didn't read or write when running on 3V3 but was fine on 5V. If anyone finds a solution, please let me know.