The device is able to count pulses from different sources – sensors or buttons – in the direction up or down. Maximum counting frequency is 10 Hz (10 pulses per second). Each received pulse is signaled audibly. Maximum capacity of the counter is 9999. Calculated value is stored in the nonvolatile memory and it is restored in the case of power failure.
• UP/DOWN counter with maximum capacity 9999.
• The calculated value is stored in the nonvolatile memory and restored in the case of power failure.
• Maximum counting frequency is 10 per second.
• 4 digits LED display with 14 mm height.
• Power supply: 7-15V DC, 0.2A.
• PCB dimensions: display: 20×60mm; motherboard: 52×57mm.
• Electronic Kit – soldering required.
The schematic diagram of the counter is shown in Figure 1. The device should be supplied with DC voltage within range from 7 to 15V connected to the POWER connector. Diode D1 protects device from faulty input polarity. Input voltage is applied to voltage stabilizer U1 type 7805, which supplies microcontroller responsible for all functionality of the counter. Bipolar transistors T1-T4 are supplying anodes of the LED digits while cathodes are directly driven from microcontrollers outputs via limit resistors R6-R12. Resistors R14-R16 pull the counter’s inputs to +5V. The piezo beeper acts as a pulse beacon. It can be turned off or switched on with the jumper JP1.
Assembly and test
The counter should be assembled on two PCBs shown in Figure 2 in the user manual. The assembly is typical and should not cause the problems. It runs in standard way starting from the smallest components and ending with the largest ones. After assembling both PCBs should be connected together with the angled goldpins.
The counter operation is simple. Shorting the UP input increases the value, while shorting DOWN input decreases. To reset the counter hold down RESET button for about 3 seconds. Inputs UP, DOWN and RESET can be connected to the any momentary switches. The piezo beeper acts as a pulse beacon. It can be turned off or switched on with the jumper JP1.
R1-R5, R14-R16: 4,7kΩ
C1, C2: 100nF
C3, C4: 100µF
U2: ATtiny2313 with 20-pin IC socket
Goldpin connector 12pin
POWER: 2-pin terminal block connector
RESET: 2-pin terminal block connector
UP: 2-pin terminal block connector
DOWN: 2-pin terminal block connector