I am using the old Zitron timer. I have half a dozen of them. I use them only to provide a 20 sec delay start and time the flight. I set my RPM in the ESC. The Zitron is a simple (some would say primitive) timer that uses nixy switch to set the time duration, no program box needed (just a small fine blade to flip switches). Basically, it is plugged into the ESC through the usual port, there is no push button to start. It starts when the power is plugged in. I have since the beginning installed a positive toggle switch in the positive battery lead. This allows me to plug in the battery pack, close everything up then start the sequence when I am ready to walk to the handle by flipping the switch. This starts the delay and then the motor. At the end of the flight we flip the switch off and then remove the batter.
When I first started in electric I would do prop test runs and simply shut off the power switch once I got the rpm and amp reading. I never had any problem but read that pulling the power when it is running could send a pulse through the system and cause setting changes. Now I always just set the run for 10 sec and let the timer run out. I'm wondering with this timer if the shut off will work buy installing it in the power lead to the timer?
Best, DennisT
Dennis,
Fig 1 Normal Zitron Setup, represents your current setup (hopefully).
For openers I would suggest you read my article “How My KR Timer Works.
https://stunthanger.com/smf/gettin-all-amp'ed-up!/how-my-kr-timer-works/Of interest is the description of the signal that comes out of the timer and drives the ESC. Regardless of the Timer brand or the ESC brand this is what the signal looks like.
The proposed setup, that follows, would allow the normal signal that comes out of the timer to pass to the ESC. This puts the Timer in control. When you press the OFF button on the key fob the signal to the ESC would go to a logic level of 0 or ground. If you press the ON button on the key fob before the timer has timed out the normal signal will once again be transmitted to the ESC. Now while the rig is in OFF mode the ESC will consider this a loss of signal. It’s unknown how the ESC handles this loss of signal. In most cases it should turn the motor OFF. However it could go to some fail-safe mode such as low power. Not likely but who knows. The next issue is what happens after a loss of signal is detected by the ESC and the signal returns to normal. Two possible actions are: Return to normal operation or stay locked out till power is cycled. I would hope for return to normal operation. That way you could practice landings until the timer times out.
Now for my proposed solution for Zitron remote OFF setup. See Figure 2, Remote OFF Zitron Timer. It is based on a 74HC08 logic element. In fact the base part number is 7408. The HC in the part number describes the type of part. I think the H stands for high power. And the C stands for C-Mos technology. Doesn’t matter. Most any part with the 7408 base number will have the same pin pattern and work the same.
The 7408 is an AND Gate. The logic rule for AND gate is a logic 0 on any of its inputs gives a 0 on the output. So in my Fig 2 diagram, if the remote switch is OFF, then the lead going to pin 2 of the 74HC08 will be at ground. This means no matter what happens on pin 1, pin 3 out will be at a 0 or ground. At this time the ESC thinks of this as a loss of signal and should stop. When you press the ON button on the key fob the NC pin of the remote switch goes open allowing the 5K resister to pull this line to a logic 1 (5Vdc). With pin 2 now at logic 1, pin 1 now has control of the gate. So the output pin 3 will track pin 1 allowing the normal signal to pass through to the ESC.
The remote switch, when powered up comes up in the OFF mode. It will be necessary to hit the key fob ON button right after you turn the power switch ON to allow the ESC to arm itself. It is possible that it will arm itself wit no signal but not likely.
This is not a project for the faint of heart. It requires mounting the 74HC08 on some kind of a board, know as a breadboard, and do a bunch of wiring. I have 50 years of experience doing this kind of work so it would be easy for me. Also I have every thing needed in my junk box.
So with that I will end this tail. As with any project this complex the only way to see if it works it to build one and test it. At this point I think it will work but who knows!
PS All this is for nougat If Figure 1 is not how your setup really looks. IE Do you really have a switch it the + battery lead. Most would call it an arming plug.