Project Start

J

jimmyhustle

Included our photos of my easily accessible stash I have lots more but as far as chips and whatnot is it in the second and last photo the last photo is a I don't know a lot of pens one two three 4 5 6 so it's a 16-pin I believe programmable

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17882903147857049259824791578297

17882903484007472426209910916270

1788290389392548240259036676205

17882903994029096784698950330994

flux

The 16-pin chip appears to be a 74HC595 shift register, not a programmable microcontroller, so it cannot control the fan by itself. The fan label confirms 12 V, 0.30 A.
For the compact PCB, I recommend sourcing an ATtiny85-20SU (SOIC-8) plus a small 5 V regulator; your K3919 can switch the fan. The board will also need a few small support resistors/capacitors beyond the originally listed parts.
J

jimmyhustle

Well could you provide me with a bare minimum design for what I currently possess and then the upgraded more marketable version and are there any parts available on the board photo included I might be able to purpose

flux

I’ll create two versions: a minimal analog controller using your existing parts, and a compact ATtiny PWM version suitable for a manufactured product. I’ll also identify which photographed salvage parts are reusable and clearly flag the limitations of the analog version.
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Created 4 tasks.
1/4 Document requirements and identify reusable photographed parts

Document requirements and identify reusable photographed parts

Create bare-minimum analog fan-control schematic

Create upgraded ATtiny PWM fan-controller schematic

Verify both designs and summarize manufacturing path

Thought for 6 sec
Referenced guidance.

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Design Notes
Photographed and Salvaged Parts
Confidently identified
  • Fan: ADDA AD0812UB-A70GL, 12 V, 0.30 A, two-wire brushless fan.
  • 16-pin IC: Appears to be a 74HC595-family serial-in/parallel-out shift register. It is not a standalone programmable microcontroller and cannot implement the requested behavior by itself.
  • Arduino Mega 2560: Usable as a development/programming platform, but intentionally reserved for a separate RFID/LCD project.
  • K3918/K3919-marked MOSFETs: Likely N-channel power MOSFETs suitable in principle for low-side switching. Confirm exact package pinout with a meter/datasheet before applying power.
  • Assorted resistors, capacitors, rectifier/signal diodes, LEDs, buttons, headers, and regulators are visible and may be reusable after their markings/values are checked.
Potentially reusable after testing
  • A diode with reverse-voltage rating at least 20 V and forward-current capability appropriate for the 0.30 A fan can serve as the fan clamp diode. A 1N400x-family part is adequate for a low-frequency prototype; a Schottky diode is preferred on the compact PWM board.
  • Electrolytic capacitors rated 25 V or higher may be used for 12 V bulk filtering. Do not use unidentified or 16 V capacitors directly across a nominal 12 V supply without confirming supply tolerance.
  • Small tactile switches can be reused as UP/DOWN inputs.
  • The existing remote LED can be reused with a verified series resistor.
Not suitable as the controller
  • 74HC595 shift register.
  • Unknown 16-pin logic ICs without readable markings.
  • The salvaged MOSFET alone cannot create discrete tap/hold speed steps.
Version A — Bare-Minimum Analog Prototype
  • Uses a capacitor-held MOSFET gate voltage and two buttons to charge/discharge it.
  • Demonstrates variable fan drive but has major limitations: MOSFET linear heating, drift, fan stall, inconsistent response, and no true digital steps.
  • With only one 1 MΩ resistor and one 550 Ω resistor, symmetric gradual UP and DOWN behavior is impossible. Additional resistors or a potentiometer are required for controlled charge and discharge rates.
  • The existing 0.01 µF capacitor is much too small for human-scale timing. With 1 MΩ it gives only about 0.01 second; practical timing requires roughly 1-10 µF depending on desired response.
Version B — Production-Intent PWM Controller
  • ATtiny85-class MCU, regulated 5 V logic, two debounced buttons, PWM MOSFET drive, LED output, fan clamp diode, supply decoupling, and programming access.
  • Firmware provides discrete tap increments and accelerated hold behavior while keeping the MOSFET fully switched rather than operated as a lossy linear element.
  • Board should provide a startup boost at 100% duty cycle before settling to low commanded speeds.
Power Budget
  • Fan: 12 V × 0.30 A = 3.6 W nominal.
  • LED/controller allowance: under approximately 0.2 W.
  • Input connector, diode, MOSFET, and copper should be designed for at least 0.50 A continuous path, with extra transient margin for startup.

  • Photographed and Salvaged Parts

  • Confidently identified

  • Potentially reusable after testing

  • Not suitable as the controller

  • Version A — Bare-Minimum Analog Prototype

  • Version B — Production-Intent PWM Controller

  • Power Budget