The purpose of this FORUM is to exchange ideas, NOT money $$$$$.
And simpler is better !
Suggestion: No board or IC, just a relay. Wire in 5 connections.
Power, Ground[Coil(-)], the N.O.(normally open) or N.C.(Normally closed) contacts..2 Leads..your output, and one jumper from the normally closed contact to the coil (+) side.
Use a 5V or 12V relay that has two sets of contacts.
( A DPDT, double-pole double-throw ). On one set of contacts, wire in your source,12V or 5V to the common connection. Then, wire in the N.C. connection to the Coil(+).
Use the other set of contacts N.O. or N.C. for your output.
What happens:
When power is applied, the relay coil energizes, thus breaking the connection on the N.C. contact..> the relay looses power.
As the relay deenergizes, the connection is made again, powering the relay. The result is that the relay cycles ON and OFF at a rate determined by the Ton and Toff times for that particular relay.
My guess is that the relay will cycle >30 Hz. If not, you can overdrive a 5V
relay with 12V. This will decrease the Ton time.