Tag Archives: GARLOW

Building a mini GPS with Atmel, Adafruit & Arduino



Oscar Liang recent debuted GARLOW, which he describes as a mini GPS watch based on the Atmel-powered Arduino Nano (ATmega328 MCU).

“Garlow stands for GPS Arduino Rechargeable Logger OLED Watch. It does what the name suggests: Accurate time, positioning related information are received from GPS satellites, [which] can be logged on SD card and shown on a OLED display,” Oscar wrote in a recent blog post.

“It can be carried as a watch or simply left at the back seat of your car as a GPS data logger. The whole system is built on the backbone of an Arduino Nano board, with a LiPo power module which enables USB battery recharge.”

Aside from the Atmel-based Arduino Nano (Uno was used for prototype), key GARLOW specs include:

  • Adafruit’s GPS Module
  • Mini SD card module
  • 0.96′ mono color OLED display
  • Power cell – LiPo charger/booster
  • 600mAh 1S LiPo battery
  • Jumper wires

“Wiring is easy and soldering is minimum. I used jumper wires so each component can be disconnected for future projects,” he explained.

“I built the case using Plastic Styrene sheet (my favorite DIY material). Everything is then glued together using hot glue, and some nylon screws and nuts.”

According to Oscar, the GPS clock draws a total current of 40mA at standby mode (OLED turned off, SD card modue turned off, only GPS working and 80mA normal operation (all on).

Current consumption is broken down as follows:

  • Arduino Nano – 20mA
  • GPS Modue – 20mA
  • OLED Display – 15mA
  • SD Card Module – 25mA

“So with a fully charged battery (600mA) it can run 13 hours on standby mode (with 10% left), and 6.5 hours on normal operation,” he added.

“[Plus], the GPS positioning accuracy is about +/- 3 meters. [The] update rate is very good which is 10Hz. It also works indoor but needs to be close to the windows.”

Interested in learning more? You can check out GARLOW’s official blog page here.