Like the title says, a nice little bidirectional level converter.

I redesigned the sht30 shield because of heat management issues… The sensor in the wemos design heats up because its above the regulator and esp module. I hope that moving the sensor and adding a thermal seperation between the bottom and top of the board helps.

Battery based card to setup connection between Arduino Pro Mini and NRF24L01+, available prototyping area.

pavouk usb dac

Recks Design & Fabrication AtTiny 85 Solar Charge Controller Rev1

ATTINY Solar Charge REV_2

Tinusaur Board v0.3.3 RC7

Arduino compatible AVR Development Board

Design Files

Shield for the Arduino Mega, supporting up to five servos (current monitored and powered separately), eight 3-pin IR sensors and eight 4-pin ultrasonic sensors

http://raphaelchang.com/#projects/bms

UNTESTED board to merge a 2.8 tft and a pi zero, with access to the gpio

Board v 2.0 Accessory feather board for Huzzah based networked temperature controller. https://github.com/cj8scrambler/eagle/tree/master/HUZZAH_TEMP_CONTROL

Mini-Board V1Atmel Mega-8 through 328

This board allows for easy programming of an Atmel AVR in the Mega-8, Mega-168, Mega-328 etc series. The board has a 10-pin ISP header along with power indication LED and a place to install an external 10 to 20 MHz resonator. The board will plug into a standard breadboard.

If using a 5v supply, the resistor should be 220 ohms, if using 3.3v supply, then use a 100 ohm resistor.

USB Interruptor

This simple board plugs inline with a USB cable. It always passes the 5V power and normally passes the USB data signals. But when you press the button, the signals are momentarily disconnected.

Why would anyone want or need such a things? Well, for the last few months I’ve been developing a USB Host Library for powerful but complex EHCI USB port in Teensy 3.6. After several false starts and re-reading the USB 2.0 and EHCI 1.0 specs and datasheet over and over (did I mention this 480 Mbit/sec USB host port is powerful but really complex), it’s finally starting to come together.

Now I’m at the stage where it’s time to begin work on code to handle USB disconnect events. When you unplug the cable, the ECHI work queues need to be removed, periodic schedule bandwidth allocation/planning needs to be undone, memory needs to be freed (hopefully it’s all findable from linked lists), hub/port status needs to be updated, and probably a ton of other stuff needs to happen that I haven’t even considered yet…

Reaching over to physically unplug the USB cable gets old quickly! Really, really old, both hands off my keyboard… right when trying to focus. With 12 Mbit/sec USB ordinary switches can usually work, but this is 480 Mbit/sec and I’m already running it through a USB protocol analyzer and a few cables plugged in tandem, leaving not much signal quality margin left. So I made this handy little board with a proper USB 2.0 high speed mux chip. The control signal is just 3.3V logic, so I might even wire it up to something to automate the process.

Admittedly, not many people develop USB host drivers and software stacks (it’s turning out to be probably the toughest coding I’ve ever done), so this little board might not have really wide applications. But here’s all the details anyway. ;-)

Update: check out this similar board, using slightly different parts.

Parts Placement

Bill Of Materials

1   Resistor, 10K, 805              RHM10.0KCHCT-ND
1   Capacitor, 0.1uF, 805           478-1395-1-ND
3   Capacitor, 1uF, 805             587-1281-1-ND
1   Diode, Schottky, B120           B120-E3/5ATGICT-ND
1   MCP1700 3.3V regulator          MCP1700T3302ETTCT-ND
1   FSUSB30 USB Mux Switch          FSUSB30MUXCT-ND
1   USB Connector, Mini-B           609-4701-1-ND
1   USB Connector, Std A            ED90065-ND
1   Pushbutton                      P8016S-ND

How to use Digikey’s website to find alternate parts when any of these aren’t in stock.

A programming adapter for ATtiny13 and similar chips.

Arduino Uno shield for 16x32 RGB LED Panel with external push button and optocoupler for triggering additional switch.