Tag Archives: Oscar Liang

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.

ATtiny4313 is under the hood of this bike light

A Maker by the name of Oscar Liang recently designed a DIY programmable bike light using Atmel’s ATtiny4313 microcontroller (MCU).

“Most bike lights on the market are some dummy red LED with just a switch, which might be running off some AA batteries. That is boring as hell and swapping out the battery once every few days seems to be a pain,” Liang explained in a recent blog post.

“The entire system is built on the backbone of an ATtiny4313 chip with a few other parts totaling at about $35. This build covers a lot of ground. You not only get safety-centric feature, you also get a handy USB charging facility and programmable LED display.”

Aside from Atmel’s versatile MCU, key project components include:


Powercell Lipo charger and booster
  • 300mA 1S Lipo battery
  • WS2811 RGB LED strip
  • Resistors, capacitors and wires

On the software side, Liang says the code written for the project is interchangeable for ATtiny and a full-fledged Arduino board – with pin numbers as the only changing variable.

“You can write the program in the Arduino IDE and upload the code to the ATtiny via an Arduino,” said Liang.

“The Arduino in this case act as a programmer, which is relatively easy to do.”

Currently, Liang’s ATtiny4313-powered bike light offers the following five primary modes or patterns:

  • Loading Red Dot – 1 LED is on at all times
  • Switching 3 LEDs – Utilizes 3 LEDs
  • Breathing Red Light – All 6 LEDs are operating
  • Dimming White and Blue Light – 6 LEDs are on
  • Colorful Rainbow Mode – Includes all 6 LEDs

In terms of future improvements, Liang says he is thinking of implementing a number of upgrades, such as sun light detection, solar charging and building a waterproof/resistant case to protect the MCU and other electronics.

Interested in learning more about the ATtiny4313-powered bike light? You can check out the project’s official page here.