Shared Projects

NOTE: This board has been replaced by DRSSTC Bus Supply V1 and DRSSTC Bridge V2 as a modular pair.

Full-Bridge power circuit for running a small desktop Musical Tesla Coil from 110/120 VAC. This design features a Soft-Start power-up circuit and relay controlled power-off voltage bleeder circuit. Note: Soft-Start and power rectification circuits are NOT compatible with 220/240 VAC! Recommend using 2oz Copper.

This board is designed to be driven by the Dual-Resonance Solid-State Tesla Coil Driver board.

The debut performance for this board was during Shock-or-Treat Halloween 2018, and can be viewed at: http://mediadrop.dewtronics.com/media/media/shock-or-treat-halloween-2018.

Note: This board is still in the prototyping/testing phase and hasn’t been fully qualified yet. Build at your own risk.

ERRATA: Do NOT build this circuit as-is. The soft-start circuit has a design flaw that causes SCR (D29) to false trigger early and to “bounce”, which causes the Soft-Start Relay RL1 to chatter and fuse its contacts due to the high inrush current, ruining the relay. The high inrush current will then fry one or both mains input rectifier diodes D32 and/or D33, and then blow the fuse.

If building, do not install the following components: RL1, D29, D30, D31, R5, R6, R7, R8, R9, RV1, C2, and R14. In the place of R14, install a NTC Thermistor Inrush Current Limiter, such as Ametherm MS22-10008 (DigiKey: 570-1003-ND) – note that this can be installed between pads 41 and 44 of the RL1 footprint for closer pin spacing, but give it plenty of air space and ventilation, as it will get hot. You can also use a variac to slowly bring up power to the entire circuit – but you’ll need to start it at around 70 volts to keep the Bleeder Relay RL2 from chattering.

Also, resistor R10 needs to be a sufficiently high wattage part. It will have about a 155-160Volt drop at 3.3mA, which is 530mW. So, use at least a 3/4Watt resistor for R10 or risk it leaking its “magic smoke”.

Note that at circuit power-down, resistor R15 will get a little toasty. This is normal. However, your driving circuit should monitor the ‘fault’ pin (pin 3 of J1) and shutdown all AC input if the fault condition (i.e. Relay RL2 open) exists for more than a few seconds, as the 2.5W rating of R15 is only sufficient as a bleeder resistor for the system. A continuous load resistor of that value would have to be around 120Watts. If the 2.5W part was left in the circuit very long (longer than the required voltage bleed down period), it would either burn in two or catch fire.

Also, cut the copper-pour trace for the ground fill where it runs underneath the fuse holder. Failure to do this will cause a short between the 120VAC mains and ground under the 120VAC-input end of the fuse holder when the solder-mask gets breached beneath it. Apparently, I should have made the area under the fuse a keepout-area for that copper pour. It is, however, a self-correcting problem, because when it shorts, the trace, and select parts of the fuse holder, will vaporize. But it is a rather loud and startling bang, and you’ll probably have to reset the circuit breaker for your power feed.

Panel

LM317 Adjustable Regulator in a constant current configuration. The current value is set by the resistor value: Iout=1.25/R1. Mounting holes are tied to GND. The TO-220 package maybe soldered directly to the exposed pad to provide thermal relief for the regulator. The input voltage is dependent on the number of LED’s being driven and the forward voltage. Using the LM317 adjustable regulator allows most of the power to be dissipated from the regulator so you may not require a power resistor, but fixed output regulators can also be used but will likely require a high wattage resistor. Just do your power calculations. Altium Designer files are available on Github.

This is a board for the Digilent Arty A7-35 to provide 8 digits of 7 segment display. There is also an R2R D/A converter chip to play with. The zip file has a PDF schematic with the part numbers on it and there is also a folder with Verilog HDL to drive the displays.

The displays are multiplexed and control is included in the logic to light up the decimal point, or points. The decimals may be in any arbitrary pattern. There is also logic to blank leading zeros. The blanking may be turned on or off at will.

The test harness is included. I have not seen my board work, but the logic has been simulated to where I think it is correct. Also included is a constraint file. This board may work with other Digilent boards, but I only have my A7-35 in mind.

Update 2018-06-12. Contact me for an update to the Verilog HDL. [email protected]

From left to right and top to bottom.

Top of the PCB

• 220 uF Capacitor (2917)
• 75 Ohm Resistor (2010)
• 75 Ohm Resistor (2010)
• 75 Ohm Resistor (2010)
• 75 Ohm Resistor (2010)
• 75 Ohm Resistor (2010)

Bottom of the PCB

• 1.2k Ohm Resistor (1206)
• 1.2k Ohm Resistor (1206)
• 1.2k Ohm Resistor (1206)
• 0.1 uF Capacitor (1206)

8x8 Analog Multiplexer (74xx4051) - https://github.com/ellisgl/analog-multiplexer-8x8

DO NOT USE!!! EXPOSED GOLD SHORTS ALL U1 PINS TOGETHER

OAT Voltage Monitor

• C1 - C0805C104K1RACTU
• D1,D2 - 1N4001-T
• K1 - EC2-12NU
• P1,P3 - OSTTC022162
• P2 - 282834-2
• R1,R22 - RNMF14FTC820K
• R3 - RNMF14FTC91K0
• R4 - 3362P-1-203LF
• U1 - C33072APG
• U2 - MEV1S1515SC

Board from http://caitsith2.com/snes/apu.htm

Converts the PS/2 Model 25 and Model 30 weird IDE to standard IDE.

TP4056 Micro LiPo Charger

Battery-powered Arduino compatible control station. This general-purpose device is meant for productivity and wireless control of remote units such as NRFBoyLED. It consumes < 2uA when not in use and < 30mA when in use, so a small 500mAh lipo battery will last for months.

BOM

• 1 x ATMEGA328P
• 1 x CH340G
• 1 x nRF24L01+ Transceiver
• 1 x 0.95" Color SPI OLED
• 1 x MCP73831 Lipo Battery Charger
• 1 x DW01MC-SA Lipo Battery Protector
• 1 x MCP1703CB 3.3V LDO Regulator
• 1 x 3.7V Lipo Battery
• 1 x Momentary Switch
• 1 x Buzzer 12mm
• 1 x Rotary Encoder
• 4 x 22pF Capacitor
• 4 x 0.1uF Capacitor
• 1 x 1uF Capacitor
• 4 x 10uF Capacitor
• 1 x 220 Resistor
• 4 x 1K Resistor
• 3 x 10K Resistor
• 2 x 10M Resistor
• 1 x LED 3MM
• 1 x 0.5A PTC FUSE 1812
• 1 x Micro-USB Connector
• 1 x 12MHz XTAL
• 1 x 16MHz XTAL
• 2 x 2N3904 TO-92 Transistor

Please see https://www.openhardware.io/view/1/Sensebender-Micro

an oled thing, obviously, again.

Breadboard-friendly adapter for ESP-01 with 3.3v regulator and 5v level shifters for Tx, Rx, GPIO0 and GPIO2.

Regulator - LD1117 SOT223
MOSFETs - 2N7002
All Resistors - 10k 0805
C1 - 100n 0805
C2 - 10uf 0805

ESP-01 mounts OVER adapter board.

Breadboard-friendly adapter for ESP-01 with 3.3v regulator and 5v level shifters for Tx, Rx, GPIO0 and GPIO2.

Regulator - LD1117 SOT223
MOSFETs - 2N7002
All Resistors - 10k 0805
C1 - 100n 0805
C2 - 10uf 0805

ESP-01 mounts pointing AWAY from board.