Turn-key PCB assembly services in prototype quantities or low-volume to mid-volume production runs

Attiny2313 based clap detection circuit

Clap activated circuits has been for some time around. But most of them simply toggled the output. Pete have bought few cheap lamps and used them for his smart clapper project. He didn’t want to limit functionality with just turn on and off but added couple new interesting features. As normally it toggles the AC switch when there are two claps within one second. If three claps are hared within one second them PWM dimming starts until fourth clap is detected. Additionally there is another relay which may be activated with laser beam. Laser is detected with photo-transistor. Device is controller by Attiny2313microcontroller which activates two 12V halogen lamps through transistor keys, one device is controlled using relay. Microphone captures sound, then amplifies, filters it and then comparator gives a pulse that goes directly to microcontrollers external interrupt pin. Small and effective circuit that adds fun to your house. Continue reading

LED Dog Collar – keeps your dog safe at night

Ken has two dogs, one of them ‘sunshine’ likes to run around when given the chance to go out. This gives him worries since she could be hit by a car. To lessen his worries he rigged up a bunch of LEDs into a dog collar. The LEDs are connected to an AVR ATTINY2313 microcontroller. Current limiting resistors are used to regulate current that flows through the LEDs. The entire electronic set up including the ATTINY2313 and the LEDs are powered using 3 AAA batteries. The PCB was made using toner transfer method while an arduino was used as an ISP to program the ATTINY2313. The good thing about building DIY stuff in your home is that what ever you do you always find a way to utilize hot glue – the electronic components in the board is covered with hot glue, the LEDs are helt to place by hot glue and the PCB was mounted on the collar with [what else?] HOT GLUE!     Continue reading

Measuring low capacitance

Probably any standard multimeter have a capacitance measurement function. But they are limited in measuring small capacitance. Measuring below 200pF gives unreliable results. Also resolution varies around 1pF. If you’re radio amateur capacitance like 2.7pF is a common value that needs to be measured or checked. One way is to purchase precise LC meter or simply build a low cap meter from parts around you. Following design is based on Attiny2313 microcontroller which measures capacitance from 1pF up to 2500pF with 0.1pF resolution. Results are displayed on standard LCD. Unit can be calibrated with 1000pF 1% capacitor. It is available as kit or take a chance to build it as all necessary info and software is available for download. Continue reading

Attiny2313 POV

POV devices are quite popular because of their nature. With single line of LEDs you can display text messages, show animation and other stuff that fits in to matrix like display. Main disadvantage is that devise has to be waved in front of viewers eyes. But hey, you get it in size that fits in to pocket. Following project is based on Attiny2313 microcontrolelr that controls 8 LEDs and is powered by two AA batteries. Actually board size is same as battery pack, so it quite compact size. Seems it is unfinished, but the goal is to build simple GUI for uploading text messages via USB to UART. Great project that would take couple hours to build. Continue reading

Reset TinyAVR fuses with HVSP

AVR Tiny microcontrollers have a low pin count (8 or 14). Sometimes you want to all of them including Reset pin which can be turned in to normal I/O pin. But problem is that after this operation AVR becomes no longer programable bia SPI. The only trick is to use High Voltage (HV) programmer. In this case serial. So you can first program AVR via SPI, then change RESET fuse to be as I/O and revert again if reprogram is needed. And of course using HV programming mode it is convenient to reset fuses of bricked AVRs. Continue reading

AVR Tiny based GPS locator

GPS device doesn’t have to be very complex. Simple Attiny2313 microcontroller can be used to read data from SR87 GPS module and display it to 2×16 alphanumeric LCD. As GPS module transmits data through serial interface it occupies only on wire so there is plenty space left for LDC, keyboard and buzzer. Keyboard is used to enter names for marked locations that are stored to EEPROM. Again, great fun project that almost pushes microcontroller to its limits. Continue reading