johnsonm / atdim Goto Github PK

This design for an attiny-based PWM dimmer circuit is licensed under
the CERN OHL as provided in the file cern_ohl_v_1_2.txt

This project requires that you set the open-project library references
to point to a checkout of [email protected]:open-project/kicadlibrary.git
The attiny part included is a variant on the version in the atmel
library with two pins moved for cosmetic purposes.

Options:

P1 may be 0.1" pitch header or screw terminal
Place P2 (ICSP) only if ICSP function desired
Three 4mm mounting holes provided

PHOTOR1 may be a 2-pin 0.1" header to a remote photoresistor
PHOTOR1 and R1 may be omitted if light sensing is not desired

FR1 may be a fusible resistor of an appropriate rating and value
for the load if the circuit is not otherwise protected, or a
jumper if it is sufficiently protected otherwise.

RV1 may be a 0.2" pitch potentiometer, a 0.1" pitch potentiometer,
a 0.1" pitch trim potentiometer, or a 3-conductor 0.1" or 0.2"
pitch connector (header or molex) to a remote potentiometer.
If you are using a 0.1" pitch part, solder the smaller pads first
as the middle pad's through-hole is sized to accomodate the larger
legs on typical 0.2" pitch potentiometers.

R3 is an optional pull-up resistor to ensure that the MOSFET
switches off cleanly at low duty cycle as described in.
https://gasstationwithoutpumps.wordpress.com/2014/07/28/pwm-controller/

D1 is a freewheel transient suppressing diode required only for
inductive loads such as motor control.

ATTINY85-T is any ATTINY*5 through-hole part that can hold your
desired program.

For low-profile applications:
Install ATTINY*5 directly soldered, not in a socket
U1 (7805) installed with bent leads over R2 and R3
Q1 (MOSFET) installed with bent leads over ATTINY*5
Use remote or low-profile potentiometer for RV1