Bought a caliper, which looks exactly like the one used on the linked page, all other components I had at hand. Copied the code and schematic from this page:
But I can not get it working. Caliper works but Arduino can not understand the data. It should send information to serial port once every second but it sends only 0.00, although caliper is not displaying 0.00, at random intervals. Sometimes it does not send anything for minutes.
I tried changing Clock and Data pins in case I did not get them right.
5V for transistors collectors I took from Arduino, GND I connected to transistors emitters and - of digital calipers battery. On the linked site he uses BC548 transistors, I use BC546 but that should not make any difference. On my scope I can not get a clear view of the signal from caliper or of the amplified signal on arduino. I see that there are impulses but the falls and rises are blurry, maybe it is because I am using old USSR scope? Scope can display audio D-class amplifiers signal on output transistors or signals on PWM power supply FETs without a problem.
I do not have a breadboard yet (I ordered one) and components are soldered to each other via thin wires, can this cause my problem?