http://www.julianstraub.com/ Recent content on Julian Straub Hugo -- gohugo.io en-us © 2020 Julian Straub. All rights reserved. Wed, 06 Jan 2021 00:00:00 +0000 http://www.julianstraub.com/posts/programming_new_attiny_microcontrollers/ Wed, 06 Jan 2021 00:00:00 +0000 http://www.julianstraub.com/posts/programming_new_attiny_microcontrollers/ The new ATtiny-0 and ATtiny-1 microcontrollers have really nice peripherals and are promising replacements for the old ATtiny85. While others do seem to miss the ISP interface, I think the new UPDI interface is actually really neat since it allows for way smaller programming connector of only three pins instead of the six pins used for ISP. http://www.julianstraub.com/posts/flashing_bootloader_onto_arduino_mini_pro/ Sat, 03 Oct 2020 00:00:00 +0000 http://www.julianstraub.com/posts/flashing_bootloader_onto_arduino_mini_pro/ The Arduino Pro Mini comes without a USB interface for programming. This is great during operation since the board only has the minimal set of peripherals needed to operate the ATMega328p. http://www.julianstraub.com/posts/arduino_with_vim/ Sun, 27 Sep 2020 00:00:00 +0000 http://www.julianstraub.com/posts/arduino_with_vim/ Call me weird but one of my main gripes with Arduino was the UI. After having worked and coded with vim for over 5 years now, I feels like a regression to try and program in a UI that feels more like Microsoft Word. http://www.julianstraub.com/posts/power_for_pwm/ Mon, 07 Sep 2020 00:00:00 +0000 http://www.julianstraub.com/posts/power_for_pwm/ What is the (theoretical) power requirement for different micro controllers to during deep sleep and to generate a PWM signal and measure voltages? http://www.julianstraub.com/deploy/micro_power_attiny85_blinker/ Mon, 04 May 2020 00:00:00 +0000 http://www.julianstraub.com/deploy/micro_power_attiny85_blinker/ Since starting the light harvesting projects, I have been possible to run a microcontroller from harvested energy alone. Looking at the Atmel microcontroller lineup the best suited controllers seemed to be the ATtiny family ones. http://www.julianstraub.com/posts/micro_power_attiny85_blinker/ Mon, 04 May 2020 00:00:00 +0000 http://www.julianstraub.com/posts/micro_power_attiny85_blinker/ Since starting the light harvesting projects, I have been possible to run a microcontroller from harvested energy alone. Looking at the Atmel microcontroller lineup the best suited controllers seemed to be the ATtiny family ones. http://www.julianstraub.com/deploy/arduino_solar_cell_characterization/ Sun, 26 Apr 2020 00:00:00 +0000 http://www.julianstraub.com/deploy/arduino_solar_cell_characterization/ As shown in the previous post about stabilizing the voltage of a solar cell, solar cells have a characteristic U-I operating curve as shown below. http://www.julianstraub.com/posts/arduino_solar_cell_characterization/ Sun, 26 Apr 2020 00:00:00 +0000 http://www.julianstraub.com/posts/arduino_solar_cell_characterization/ As shown in the previous post about stabilizing the voltage of a solar cell, solar cells have a characteristic U-I operating curve as shown below. http://www.julianstraub.com/deploy/analog_solar_cell_voltage_stabilizer/ Thu, 23 Apr 2020 00:00:00 +0000 http://www.julianstraub.com/deploy/analog_solar_cell_voltage_stabilizer/ Solar cells are non-ideal power sources that need managing in order to derive maximum power from them. The one of the reasons are the non-negligible series and parallel resistance in solar cells. http://www.julianstraub.com/posts/analog_solar_cell_voltage_stabilizer/ Thu, 23 Apr 2020 00:00:00 +0000 http://www.julianstraub.com/posts/analog_solar_cell_voltage_stabilizer/ Solar cells are non-ideal power sources that need managing in order to derive maximum power from them. The one of the reasons are the non-negligible series and parallel resistance in solar cells. http://www.julianstraub.com/deploy/current_source_with_two_transistors/ Mon, 20 Apr 2020 00:00:00 +0000 http://www.julianstraub.com/deploy/current_source_with_two_transistors/ For various reasons we may want to control the current through a load. For example current control is a great way to drive LEDs. http://www.julianstraub.com/posts/current_source_with_two_transistors/ Mon, 20 Apr 2020 00:00:00 +0000 http://www.julianstraub.com/posts/current_source_with_two_transistors/ For various reasons we may want to control the current through a load. For example current control is a great way to drive LEDs. http://www.julianstraub.com/posts/the_appeals_of_energy_harvesting/ Sun, 19 Apr 2020 00:00:00 +0000 http://www.julianstraub.com/posts/the_appeals_of_energy_harvesting/ Energy harvesting is the process of capturing energy from physical processes such as light, vibrations, or electromagnetic fields. While there are large scale applications like solar or wind farms, I am interested in harvesting tiny amounts of energy in places that would usually not be considered power sources and doing something interesting with the harvested energy. http://www.julianstraub.com/posts/bpw34_pin_diode_light_harvester/ Fri, 17 Apr 2020 00:00:00 +0000 http://www.julianstraub.com/posts/bpw34_pin_diode_light_harvester/ Inspired by the desire for a minimal light harvester that relies on a very small and even form-able solar cell, I recently had the idea of trying to use photo-diodes for light harvesting instead of “big” solar cells. http://www.julianstraub.com/posts/stand-alone_arduino_eeprom_voltage_logger/ Tue, 14 Apr 2020 00:00:00 +0000 http://www.julianstraub.com/posts/stand-alone_arduino_eeprom_voltage_logger/ The arduino voltage logger from the previous post worked by directly sending all voltage values to a computer for logging. This way storage is virtually limitless. http://www.julianstraub.com/posts/harvesting_light_3_iterations_on_blinker/ Sun, 12 Apr 2020 00:00:00 +0000 http://www.julianstraub.com/posts/harvesting_light_3_iterations_on_blinker/ In a previous post about harvesting light with a charge pump, I described my first iteration on that classic circuit. http://www.julianstraub.com/posts/free_forming_circuits/ Sat, 11 Apr 2020 00:00:00 +0000 http://www.julianstraub.com/posts/free_forming_circuits/ After various breadboard experiments with energy harvesters, I started free-forming them as can be seen in the picture below: Free forming a circuit is an art in itself to me, because you are creating a shapable 3D artifact that is constrained by the functionality (the circuit). http://www.julianstraub.com/posts/voltage_sources/ Sun, 05 Apr 2020 00:00:00 +0000 http://www.julianstraub.com/posts/voltage_sources/ Creating a stable voltage of known quantity from a some a given input voltage (from a battery, or a solar cell for example) is a common problem. http://www.julianstraub.com/posts/arduino_voltage_logger/ Sat, 04 Apr 2020 00:00:00 +0000 http://www.julianstraub.com/posts/arduino_voltage_logger/ In order to log the discharge and charge curves of capacitors and batteries in the light harvesting devices, I programmed an Arduino Nano to be able to log the voltage on one of the ADC pins out through the serial port. http://www.julianstraub.com/deploy/energy_storage_for_harvesters/ Sat, 28 Mar 2020 00:00:00 +0000 http://www.julianstraub.com/deploy/energy_storage_for_harvesters/ Energy storage is an important topic for solar-powered devices such as explored in the harvesting light series. The two main vehicles for energy storage are (super) capacitors and lithium ion batteries. http://www.julianstraub.com/posts/energy_storage_for_harvesters/ Sat, 28 Mar 2020 00:00:00 +0000 http://www.julianstraub.com/posts/energy_storage_for_harvesters/ Energy storage is an important topic for solar-powered devices such as explored in the harvesting light series. The two main vehicles for energy storage are (super) capacitors and lithium ion batteries. http://www.julianstraub.com/deploy/harvesting_light_2/ Sat, 21 Mar 2020 00:00:00 +0000 http://www.julianstraub.com/deploy/harvesting_light_2/ Building the pretty straight forward light harvester described in a previous post, I learned that that design is somewhat passive: the harvester just charges the whole day and then discharges for 1-2h (depending on the capacitor) once it gets dark. http://www.julianstraub.com/posts/harvesting_light_2/ Sat, 21 Mar 2020 00:00:00 +0000 http://www.julianstraub.com/posts/harvesting_light_2/ Building the pretty straight forward light harvester described in a previous post, I learned that that design is somewhat passive: the harvester just charges the whole day and then discharges for 1-2h (depending on the capacitor) once it gets dark. http://www.julianstraub.com/posts/sensing_light/ Sun, 15 Mar 2020 00:00:00 +0000 http://www.julianstraub.com/posts/sensing_light/ Sensing the amount of light falling on a surface is at the core of how any more advanced light sensors such as human or animal eyes function. http://www.julianstraub.com/posts/programming_arduino_in_c/ Sat, 14 Mar 2020 00:00:00 +0000 http://www.julianstraub.com/posts/programming_arduino_in_c/ In this post, I describe how to program an Arduino straight up in C using a simple Makefile. Arduino microcontroller boards like the Arduino Uno or the Arduino Nano are great for tinkering, since they come with all the necessary circuitry to get started right away. http://www.julianstraub.com/posts/creating_light/ Wed, 11 Mar 2020 00:00:00 +0000 http://www.julianstraub.com/posts/creating_light/ Light is one of the most fundamental parts of our experience of the world. Without it our main sensor, our eyes, would not function. http://www.julianstraub.com/posts/creating_light_with_transistor_current_source/ Wed, 11 Mar 2020 00:00:00 +0000 http://www.julianstraub.com/posts/creating_light_with_transistor_current_source/ In the initial post on creating light we saw the that the simplest way to generating light is using a LED and a resistor to limit the current through the LED. http://www.julianstraub.com/posts/harvesting_light/ Mon, 09 Mar 2020 00:00:00 +0000 http://www.julianstraub.com/posts/harvesting_light/ Light emitted from the sun is the basis of most live on earth (with the exception of creatures living of of deep sea thermal vents). http://www.julianstraub.com/about/ Sun, 08 Mar 2020 00:00:00 +0000 http://www.julianstraub.com/about/ While my work and research is about developing 3D machine perception, I have always enjoyed creating electro-machincal contrations for fun (Plicro, Roboking, Ca3505, Kno0Bot, Kno2Bot, Holomove, rEIzor, RoboSoccer Lab). http://www.julianstraub.com/posts/math_mode/ Sat, 07 Mar 2020 00:00:00 +0000 http://www.julianstraub.com/posts/math_mode/ Math is important for a engineering/science focused blog such as this one. I found a great post that describes a nice way to enable latex-style math mode in Hugo that works with and without javascript. http://www.julianstraub.com/drafts/solar_harvesting_ic_review/ Mon, 01 Jan 0001 00:00:00 +0000 http://www.julianstraub.com/drafts/solar_harvesting_ic_review/ Analog Devices: - LTC3105 doesnt do battery management for you. The LDO output is ony on when power is present on the input.