Ken Bauer is ready to accept orders for the "SS-DT", (Sub Sunk-Deadman Timer), at $30.00 a piece plus $5.00 shipping and handling. I've purchased two units already.
Send Checks or use PayPal to:
2306 Turquoise Circle
Chino Hills, CA 91709
"For mail orders in the US sending a check is good. Paypal works great but please add an extra 2% to the total to help offset the money that these guys keep in the process. Send paypal to: firstname.lastname@example.org."
You might want to email Ken when you send in your order and please copy me so I can keep track of who is getting units.
The unit will be programmable in 5 minute intervals. Up to 40 interval counts can be programmed into the SS-DT so that will give us a range of between 5 minutes and a maximum of 200 minutes for Time-outs.
There are only two servo positions, the normal initial position and the DT or release position. A couple of seconds after the DT times out the servo moves back to normal position and will not go to DT position again until another full cycle timeout. You can restart the timer as many times as you want either by pressing the button or powering it up, but the servo will just stay in the initial position. The timer sends a command to the servo to go to the first position with each power up, but if it is already there it won't move.
One useful note. The timer provides not only a signal wire to the servo but also a power wire and a ground wire. The signal wire carries the pulse signal that tells the servo where to go. The power wire is controlled by a mosfet switch so that the servo is only powered on and using battery power during the one second period when it is moving. This is significant because this power signal can be used to control a device directly rather than using a servo. For example the solenoid could be connected directly between the power wire and the ground wire which would be much simpler than using a servo. This switch is good for about 200 to 300mA.
If 200 to 300mA is not enough power to drive your solenoid directly you could use it to drive a small relay that could then be used to complete the circuit between a battery and a large solenoid.