Sequential Timer Specs - doc00033
The circuit is a two stage sequential timer with
auto reset. It can turn a Solenoid On/Off after a
Sequence of delays that are preset. This is also a
basic example of timer usage in automation.
You can make very simple Timers with 555 also - Display
On Timer with 555
Sequence Of Operation -
The Source design files for this project are here -
Stage Sequential Timer Docs
- Power on the Circuit.
- If Start switch is pressed.
- Then after Timer Delay T1 Secs the
Solenoid Operates in Forward Direction.
- Next after Timer Delay T2 Secs the Power
to Solenoid is cut off.
- Timers are Reset.
- Circuit Ready for next press.
All Timers are 1 - 30 Secs Analog with Presets to
adjust with a screwdriver. The Switch, Solenoids and
Power supply has to be via terminal blocks or
plug-jacks. The PCB may be upto six Square Inches
for standard DIP components but with SMD it may be
LED Annunciators -
RED LED - indicates battery needs charging, battery
is dead. will go off when battery has been charged.
YELLOW LED - indicates power is coming from adapter.
will go off if mains supply is off or adapter is not
GREEN LED - Indicates Start was pressed and process
in on. will go off when the 2 timers are done -
reset and cycle is complete.
RED LED - Indicates solenoid is on. will go off when
solenoid is off.
The LEDs can be grouped in two sets on PCB or
enclosure as specified. Specify if LEDs have to be
on PCB to the PCB designer or ask him for a
connector arrangement for remote panel LEDs.
Solenoid Specifications -
Volts - 12V, Current max - 500mA, surge
- 1.2 Amps, coil - > 30 ohms. Type
solenoid specs changed so as to make circuit
smaller. There in no movement on reversal of
User End Inputs -
A provision for both START and STOP switches
will be present, you can omit the STOP. Power supply
to circuit : 18V - AC, 1.5 Amps, low voltage
isolated, transformer or mains adapter. quality of
transformer will determine product safety !
Battery - 14.4 volt 1000 mAH Prismatic Li-Ion
Have a look at this Interesting Project which will
develop your skill - Mikes
Optical Timer Counter
Method of work :
- The Circuit will be sent to you after you
approve this page of specs.
- The Circuit must be prototyped on breadboard
at your end and tested.
- All troubleshooting help will be provided by
- You then need to make a PCB for the circuit
and have it built by vendor.
- The circuit and technologies in the circuit
will be open source.
The PCB has to be tested to conform with the
circuit, this has to be Meticulous. The Circuit is
for the Battery and Solenoid Specified and will have
to be modified if battery and solenoid are
different. D1 to D4 can be replaced by a 300V 3A
Bridge Rectifier Module. F1 fuse could be 2A - 3A
Slow Blow depends on Solenoid inrush current.
Presets can be with some graduations if possible for
ease of adjustments. LED resistors can be a bit
lower if more brightness is required.
Then try these modifications if you have problems.
In del90005.pdf change C12 10pf to 68pf.