Shared Projects

Small footprint Si5351a-based transmitter with TCXO reference, intended for flight / telemetry

Github link with schematic, pictorial, BOM, gerber and photos: https://github.com/stefanoaz/BeaconTXv1a

This transmitter was designed to be a replacement for existing Si5351a based synthesizer breakout boards, for applications requiring small size, light weight and TCXO reference frequency stability. For flight telemetry from a superpressure balloon, the board also incorporates static bleed resistors on the Clk0 and Clk1 outputs, which are intended to drive a dipole.

This module is a drop-in replacement for the synthesizer board used by Ken Daniel for his airborne beacon described here: https://github.com/kenndaniel/K9YO_WSPR Benefits are that it saves about 2 grams of weight vs the Adafruit synth, and is more temperature stable.

General purpose shield for WEMOS D1 mini with I2C and output to a FET. Could be used to drive lights, heater, fan, using I2C input of temperature & humidity. Work in progress.

The ItsyBitsy M4 Charger Backpack is an Adafruit ItsyBitsy M4 Express-compatible piggyback module that converts the 3-sided pinout of the ItsyBitsy to dual in-line for use on typical solderless breadboards and soldered protoboards. The adapter was also designed with extra solderable pin connections.

Included is a STEMMA-QT connector that can be optionally configured via solder jumpers to connect to the ItsyBitsy’s UART (RX/TX) or I2C (SCL/SDA) signals. A 2-pin JST LiPo battery connection is on-board that supports charging (100mA charge rate), compatible with Adafruit’s standard battery connector polarity.

6 channel NMOSFET driver

A piggybottom LiPo charger board for attaching underneath an Adafruit ItsyBitsy NRF board. A 2-pin JST LiPo battery connection is on-board that supports charging (100mA charge rate), compatible with Adafruit’s standard battery connector polarity.

This board takes standard definition video and breaks it out into a buffered video output with gain, a horizontal and vertical scan ramps (for driving XYZ monitors) and several important video pulses (CMOS TTL levels) for the serious TV experimenter. With a couple of my other boards, it is possible to construct a complete television monitor using surplus electrostatic CRTs in the one to five inch screen size range. This board is smaller than v1 and is a lot lower in price. Fundamentally, the two circuit versions are the same. I recommend this version over my earlier for cost reasons.

Non-Electronic Add-On For the Defcon31 Conference Badge

ESP BAB

This is a simple circuit that will turn on an ATX power supply using a momentary switch. I made this specifically to use an AT style motherboard in an ATX case, however, you could use this generically in any case that you want to turn an ATX PSU on/off using a momentary switch.

The mounting hole is sized to fit a 6-32 screw so that you can mount the board using a standard motherboard standoff.

If using one of those common AT-to-ATX power adapters, you will most likely have to add a pin/wire for the +5VSB signal.

A parts list is silkscreened on the back of the PCB. Resistors and capacitors are 0805 size. You can use standard 2.54mm single row pin headers for the switch and PSU connections.

This has been tested using an AT motherboard and ATX power supply for several hours and found to work as intended. But as always, use at your own risk.

This circuit was taken from a post found on Stack Exchange. More info can be found here: https://electronics.stackexchange.com/questions/186841/momentary-button-as-switch