Resources
Free tools, reference links, and utilities to help you diagnose, fix, and upgrade — curated by J.D. Sweeney.
DiagnosticSignal Free Tools
OBD-II Code Lookup
Look up any P, C, B, or U diagnostic trouble code. Includes symptoms, likely causes, and severity rating.
PC Upgrade Path Finder
Enter your laptop model and find out exactly what RAM, SSD, and Wi-Fi upgrades it supports.
Subnet Calculator
Calculate network address, broadcast address, host range, and usable hosts from any CIDR notation.
Wire Gauge Calculator
Find the correct AWG wire gauge for any circuit based on current, length, and voltage drop tolerance.
Barcode Identifier
Identify barcode format from the number — UPC-A, EAN-13, Code 128, ITF-14, QR, and more.
4-20mA Current Loop Calculator
Scale a 4-20mA, 0-10V, or 1-5V signal to engineering units and back, with % of span and NAMUR fault flags.
RTD Pt100 / Pt1000 Calculator
Convert RTD resistance to temperature and back (IEC 60751), for Pt100 and Pt1000 sensors.
PoE Power Budget Calculator
Check your access points, cameras, and phones against a switch's PoE budget before you buy.
Modbus Register Decoder
Decode holding registers into int/uint/float across all four byte orders — find the right one fast.
Motor FLA & VFD Sizing Calculator
Full-load current from HP/kW, voltage, phase, PF, and efficiency, with a VFD sizing hint.
UPS Sizing & Runtime Calculator
Size a UPS from load watts, or estimate battery runtime — with realistic derating.
Tire Size Comparison Calculator
Compare two tire sizes for diameter change, speedometer error, and safe-swap range.
Fuel Trim Interpreter
Turn STFT/LTFT readings into a lean-vs-rich, vacuum-leak-vs-fuel-delivery diagnosis.
PSU Wattage Calculator
Estimate PC power draw and get a right-sized power-supply recommendation.
RAID Capacity Calculator
Usable capacity and fault tolerance for RAID 0/1/5/6/10 and JBOD.
IP Camera / NVR Storage Calculator
Estimate storage for a camera system from resolution, fps, mode, and retention.
Password Strength & Entropy Calculator
Entropy in bits and crack-time estimates, computed entirely in your browser.
Reference & External Tools
Vehicle Diagnostics
EPA guide to what readiness monitors mean for emissions testing
Search for Technical Service Bulletins and recall information by VIN
Professional technician forum for complex diagnostic questions
PC Hardware
Free utility to identify your exact CPU, RAM, and motherboard specs
Comprehensive hardware info and monitoring — useful for finding M.2 slot details
Compare upgrade paths with real-world performance data
Networking & Electrical
NFPA published ampacity tables for wire sizing reference
Web-based IP subnet calculator with binary breakdown
Free packet analyzer for network troubleshooting
Industrial & Barcode
Free scanner configuration utility from Zebra Technologies
Official GS1 standard definitions for barcode formats
Configuration software for Honeywell barcode scanners
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