The Amp Hour Electronics Podcast

The Amp Hour Electronics Podcast


#202 - An Interview With Brandon Harris - Impish Internet Iamatology

June 10, 2014


Welcome Brandon Harris of Electric Imp!



  • Hugo started the company after leaving Apple (after briefly working at Nest). He worked on an Apple stock notifier (that turns green or red depending on stock direction). The frustration around connecting XML and JSON lead to the Imp.
  • Brandon and Hugo worked together at Apple on the iPhone.
  • Around the Electric Imp offices, one of the employees made the “IoTEA”, a notification system for when the kettle is ready.
  • Electric Imp wants to be the AWS of IoT.
  • There are currently three different versions of Imp hardware:

    • IMP001 is the SD card.
    • IMP002 is the solder down device.
    • IMP003 is the lower cost, no antenna module manufactured by Murata.


  • Each of these has the Broadcom wifi chipset, the same used in iPhones.
  • The main processor is the STM32 Cortex M3.
  • The coding language for the Electric Imp is Squirrel. They started with Lua, both of which are scripting languages.
  • The application team created a freefall detection device, something you throw in the air and it connects to the internet and sends a packet before returning to your hands.
  • DHCP is the slowest step in the connection process.
  • The Imp runs eCos, they call it impOS.
  • Using the SD card you are limited to 6 pins, it can help to use an i2c expander. Bit banging has to go through the SPI port.
  • Because it is an RTOS instead of a superloop, it can be a tough adjustment for normal Arduino users.
  • The Nora reference design is a multi sensor design with qualification of the power. Quirky has a similar product called Spotter.
  • There are a wide variety of other reference designs to pull from.
  • The sleep modes sip current in different modes:

    • Deep sleep: 4-6 uA wakes on timer or interrupt
    • On with wifi off: 1-2 mA
    • On with wifi on: 5-6 mA
    • Everything on: 100 mA


  • Nora reference design has battery info/comparison. It gets roughly 60K wakes on 2 AA alkalines. Nora does 15 mins between uploads, 1 min wake for each read.
  • Wifi is TDMA.
  • BlinkUP is how you get the info into a device, it uses a phototransistor on the bottom of the SD card (or you have to add one)
  • Adam Wolf told us about how they do something similar at Wayne and Layne.
  • Brandon hopes future products will try bluetooth, cellular.
  • They tried to put their reference designs into the public domain, which wasn’t allowed. Instead they licensed with the X11 open source license.
  • All of the necessary code and drivers for the Electric Imp are on their Git Hub repo.
  • Their main competition is SparkCore; the differentiating factor is that Spark allows you to run on their servers, whereas Electric Imp helps to make the process smoother.