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Superprobe

I came across the Super Probe two weeks ago, and just had to make one. I had a bunch of the PIC 16F870 microcontrollers left over from an earlier project, and the rest of the parts were all easily found in my parts collection.

superprobe1

It is a really simple circuit, with so many useful features: - Logic Probe (L 3.7 V, P > 0.5us pulse) - Logic Pulser (0.5 us pulses at 5, 50, 500, 5k Hz) - Frequency Counter (8 digits) - Pulse Counter (8 digits) - Voltmeter (max 5 V, readings are a little high) - Diode measurement (measures fwd voltage using 5V supply via 10k resistor) - Capacitance measurement (1nF to 500uF, approx 100pF resolution) - Inductance measurement (100uH to 999.99mH, but not very accurate) - Signal generator (0.5 V square ware @ 500 Hz) - NTSC video generator (white dot pattern) - ASCII test pattern (A-Z then CR/LF at 1200, 2400, 4800, or 9600 baud) - Midi test output (plays middle C on selected midi channel) - R/C servo test output (approx 770 to 2300 us pulses @ ~28 Hz for servo control) - Square wave output (1 to 9999 Hz 5V square wave) - Pseudo random output (10 kHz PRNG) - IR test output (38 kHz 50 % duty cycle square wave for IR receiver testing) - PWM test output (6 kHz square wave with 3 % to 97 % adjustable duty cycle) In addition to the PIC, you just need 4 common anode 7-seg LED displays, a 20 MHz crystal, and a few resistors, caps, etc. I found the display to be a bit dim, but the MAN6610 7-seg displays I used were quite old and would be rated quite low in brightness. I left off the LM2931 regulator as I will just power it off 5 V, and so I actually put a PIC ICSP connector on the end of the board for re-programming, and an easy way to connect power. We are looking to make up a PCB for this so that members can make their own. It is a bit of a pain wiring up the 7-seg LED’s (using the LTC4627 would help a lot). - Kean