Hardware Podcasts

278: Bricks' Batteries Last Forever (Repeat)

Embedded.fm · 11 Feb 2022 · 1h 06m · Episode 278

What this episode covers

Matt Liberty, founder of Jet Perch, discusses the design and development of Joulescope, a high-precision current measurement tool launching via Kickstarter. He explains the engineering challenges of measuring dynamic ranges spanning nine orders of magnitude, from nanoamp sleep states to amp-level active currents, and how standard multimeters fail due to burden voltage and resolution limits. The conversation covers software strategies for low-power embedded design, such as managing GPIO states and clock speeds, and details the hardware innovations in Joulescope, including its auto-ranging shunt resistors and electrical isolation.

Most relevant to

early-stage companies

Topics

Mentioned

Companies
Jet Perch
Products
Joulescope, ChipWhisperer, uCurrent
Also
Colin O'Flynn, Jacob Beningo

Related episodes from other shows

Other shows on the same ground, closest first.

  • The Amp Hour · 1h 20m

    Measuring Current with Matt Liberty

    Matt Liberty, creator of Joulescope, explains the engineering challenges of measuring high dynamic range currents in low-power IoT devices, specifically addressing the difficulty of switching between milliamp active states and microamp sleep states. He details how Joulescope uses a shunt ammeter design with seamless auto-ranging to minimize burden voltage, preventing device brownouts, and leverages Lattice iCE40 FPGAs for precise, sub-microsecond switching. The conversation covers practical applications for optimizing firmware power profiles, debugging leakage currents from components like bypass capacitors, and managing the supply chain and manufacturing processes for a small-batch hardware startup.

    Batteries & low-power designPCB design & layout
    10 chapters

  • The Amp Hour · 1h 15m

    The Joulescope Upgrade with Matt Liberty

    Matt Liberty, founder of JetPerch LLC, discusses the launch of the Joulescope JS220, an upgraded high-dynamic-range current and voltage measurement device. He details the hardware evolution from the JS110, including the switch to a Lattice ECP5 FPGA, a Cortex-M7 microcontroller, and a 16-bit ADC, while explaining the custom firmware architecture and publish-subscribe protocol. Liberty also shares his experiences navigating the global chip shortage, managing supply chain risks with PartsBox, and the financial pressures of bootstrapping a hardware business.

    Scaling productionSourcing & supply chain
    8 chapters

  • The Amp Hour · 1h 07m

    The Nerd Calendar

    Chris Gammell of Contextual Electronics and Dave Jones of the EEV Blog discuss the Narrative wearable camera, highlighting its low-power engineering challenges involving GPS, Wi-Fi, and battery life. They analyze the difficulty of measuring wide dynamic range currents in DC power analysis, noting that specialized equipment like the Keysight DC Power Analyzer is prohibitively expensive for general use. The conversation also covers the collapse of Theranos, the IEEE's acquisition of GlobalSpec, and practical advice for engineers regarding data sheets, jellybean components, and RF design.

    Batteries & low-power designTest & measurement
    9 chapters

  • The Amp Hour · 1h 08m

    Sipping Coulombs

    Dave Jones of EEVblog and Chris Gammell of Contextual Electronics discuss the business realities of hardware, including the bankruptcy of Chip Board and the supply chain constraints facing Jones's own multimeter production. They analyze the economics of low-cost single-board computers like Raspberry Pi and the challenges of designing for long battery life, using a hypothetical keychain device to illustrate power budgeting with primary lithium cells and BLE. The conversation also covers the culture of Defcon badges, debunking pseudoscientific wireless charging claims, and the importance of validating product requirements early.

    Batteries & low-power designSourcing & supply chain
    9 chapters

  • The Amp Hour · 1h 17m

    A Total 360

    Dave Jones and Chris Gammell celebrate The Amp Hour's 360th episode with a live-streamed Q&A, discussing Dave's upcoming production of 50 early-release multimeters and his decision to stock a premium Japanese pocket multimeter. They brainstorm the design of a portable 'micro supply' power supply, debating the use of the LTC3780 buck-boost controller, battery options like 18650 cells, and noise reduction techniques. The conversation also covers industry news, including John Deere's acquisition of Blue River Technology, the failure of Juicero, and the technical challenges of designing portable lab equipment.

    PCB design & layoutAnalog & power electronics
    7 chapters

The summary, chapters and topics are generated from the episode’s audio by this directory, not written by Embedded.fm. The episode itself belongs to its publisher.