ULN2003 – practical example of «reading» microchip schematic via Evil Mad Scientist
We often receive comments that while out microchip photos are beautiful and interesting, it is completely unclear how integrated circuit implements basic elements and form larger circuit. Of course it is impossible to do a detailed review of an 1’000’000 transistor chip, so we’ve found simpler example: ULN2003 – array ofDarlington transistors.
Despite it’s simplicity this microchip is still widely used and mass manufactured. ULN2003 contains 21 resistors, 14 BJT transistors and 7 diodes. It is used to control relatively high load (up to 50V/0.5A) from microcontroller pin. Canonical use case – to control segments of large 7-segment LED displays.
What’s inside the ULN2003 Darlington driver chip - [Link]
The MAX15062 high-efficiency, high-voltage, synchronous step-down DC-DC converter with integrated MOSFETs operates over a 4.5V to 60V input voltage range. The converter delivers output currents up to 300mA at output voltages of 3.3V (MAX15062A) and 5V (MAX15062B). The device operates over the -40°C to +125°C temperature range and is available in a compact 8-pin (2mm × 2mm) TDFN package. Simulation models are available.
MAX15062 – 60V, 300mA, Ultra-Small, High-Efficiency, Synchronous Step-Down DC-DC Converters - [Link]
How to capture and reverse engineer an infrared IR code and use an Arduino or other microcontroller to replay the command. Oscilloscope and logic analyser capture, coding, troubleshooting, tounge angle, it’s all here.
In this instance Dave captures the NEC (Japanese) code from his Canon video camera remote control on the digital oscilloscope, figures out all the bits and encoding, and writes an Arduino library to replay the code back, and verifies it with his Saleae Logic logic analyser.
EEVblog #506 – IR Remote Control Arduino Protocol Tutorial - [Link]
This is a collection of high input voltage, step-down switching regulators from Maxim Integrated
76VIN step-down switching regulator; 500mA output; external catch diode
60VIN step-down switching regulator; 500mA output; low parts count
60VIN step-down switching regulator; 1A output; low parts count
76VIN step-down switching regulator; 1A output; external catch diode
60V, 300mA, ultra-small, high-efficiency, synchronous step-down DC-DC converter. This is the industry’s smallest high-voltage synchronous buck voltage regulator.
AntzyP @ instructables.com writes:
What’s with mint boxes and electronics? Beats me, but they are somehow made for each other. I had built ladyada’s USBtinyISP v1.0 circuit on a breadboard which I used every other day. It worked sporadically(and never at hour of need), used up half of my breadboard and looked ugly. So I decided to try my hand at home PCB fabrication and build it in, of course, a tiny tic-tac box. Since I was a beginner, the circuit is easy and single-sided and uses crystal instead of ceramic oscillator.
Tic-Tac USBtinyISP Programmer - [Link]
Digital Temperature Sensor in TO-92 Package Ideal for Measuring Ambient Temperature.
The MAX31820 ambient temperature sensor provides 9-bit to 12-bit Celsius temperature measurements with ±0.5°C accuracy over a +10°C to +45°C temperature range. Over its entire -55°C to +125°C operating range, the device has ±2.0°C accuracy.
MAX31820 – 1-Wire Ambient Temperature Sensor - [Link]
AntzyP @ instructables.com writes:
Cap’n ArrDrownHo! is the lovechild of Ardweeny and Boarduino and he’s here to commandeer your AVR ships. ArrDrownHo! inherits pros of both and cons of neither. Pick up an AVR chip and start prototyping instantly on a breadboard! Want to replace that costly Arduino in your project with a cheap AVR, but don’t know how? Use the simple plug-and-play ArrDrownHo! piggybacked onto the AVR to act as interface for programming and provide power.
ArrDrownHo! – Easily convert AVR to Arduino - [Link]
Niek designed this BareDuino micro, that is available at github:
For some Arduino projects, you don’t actually need that many IO pins. That’s exactly the case when I tried to build a simple RGB throwie that would cycle through colours. I was looking for a cheaper alternative to the Arduino UNO’s ATmega328P when I stumbled across this post by MIT’s High-Low Tech lab. They developed a library for programming the 8-pins ATtiny45/85 from the Arduino IDE. It’s a very smart solution to use permanently in some low pin-usage projects, but you still need to hook up individual wires from your programmer to the ATtiny to be able to program it. That’s when I came up with the idea of the BareDuino Micro.
BareDuino micro - [Link]
This is a flyback SMPS that will boost voltage a voltage of around 20V to 40V, or more if you change the feedback resistors. It uses an off the shelf transformer from CoilCraft. The LM3479 is a nice controller because it’s frequency of operation can be set by changing R1. At 39K it runs at about 500KHz.
Flyback Switch Mode Power Supply Circuit - [Link]
When the circuit is powered up, all of the transistors are off and stay off. C1 gets pulled up to Vp. When the switch is pushed, Q3 and Q2 turn on, since their base is pulled up. Q1 and Q4 are in turned on as well. Q1 keeps Q2 turned on and Q2 keeps Q3 turned on and Q3 keeps Q4 turned on. Q4 supplies current to the load. When Q2 is asserted it keeps pin 1 of SW1 at ground.
When the switch is pulled low again, the base of Q3 is tied to ground, because Q2 is on, and the chain is broken an all of the transistors turn off.
C1 and R1 and R5 form the time constant for the debounce circuit. Adjust these values for an appropriate debounce time.
Latching Momentary Switch for breadboard - [Link]