Embedded power and energy analysis with a precision Joulescope JS220
Current and voltage are sampled at 2 million samples per second with autoranging that keeps nanoamp sleep currents and multi-amp bursts on the same continuous trace, without disturbing the device under test. I use it to answer exactly how much energy your firmware spends, and where it goes.
Send me your problem See services| Time (ms) | Current | Voltage | Power | Event |
|---|---|---|---|---|
| 0.000 | 1.8 uA | 3.30 V | 5.9 uW | Deep sleep |
| 412.000 | 1.8 uA | 3.30 V | 5.9 uW | Deep sleep |
| 412.050 | 4.2 mA | 3.29 V | 13.8 mW | MCU wake, sensor read |
| 412.180 | 26.4 mA | 3.24 V | 85.5 mW | BLE advertising burst |
| 412.183 | 1.9 uA | 3.30 V | 6.3 uW | Return to sleep |
Services
Engagements are limited to power and energy measurement on battery-powered and embedded devices.
- Battery life estimation
- Measured average current translated into real-world battery life for a given cell capacity, based on your device's actual duty cycle rather than datasheet assumptions.
- Sleep and standby current verification
- Nanoamp-level measurement of deep sleep and standby states, where a few microamps of unexpected draw can dominate total battery drain.
- Firmware-level energy attribution
- Correlating current waveforms to specific firmware operations, such as a sensor read, a flash write, or a BLE advertisement, to find which routines cost the most energy.
- Wireless radio power profiling
- Measurement of BLE and Wi-Fi advertising, connection and transmit events, to quantify the energy cost of radio activity against the rest of the duty cycle.
- Inrush and startup current analysis
- Capture of power-on and wake-up current spikes at full bandwidth, to check against supply rail limits and USB inrush requirements.
- Coin cell and low-power source validation
- Assessment of how pulsed loads interact with a CR2032 or similar cell, including voltage sag under load and its effect on system behavior.
- Comparative and regression testing
- Before-and-after measurement across firmware revisions or hardware variants, to confirm that an optimization actually reduced energy use.
- Deliverables
- A written findings report, raw capture files, and specific recommendations for firmware or hardware changes that reduce energy consumption.
Engagement process
A defined process with clear outputs at each stage.
- ScopingYou describe the device, power source and what you need to know. I confirm whether this measurement approach fits.
- Capture and analysisThe device runs its normal duty cycle while current, voltage and power are recorded and analyzed.
- ReportingYou receive the findings, capture files and recommended changes.
Scope of work
Services cover DC current, voltage, power and energy measurement on devices powered at typical embedded and battery voltages.
AC mains measurement, high-voltage systems and destructive testing are not offered. If a problem needs one of these, I will say so at scoping.
Request an engagement
Send a short description of the device and what you need measured. I will reply with an assessment of whether and how this can help.