---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Sat 10/14/17: 13 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 02:47 AM - Re: Re: Constructing an automatic RCA video camera feed splitter (Robert L. Nuckolls, III) 2. 06:03 AM - Re: Constructing an automatic RCA video camera feed splitter (Eric Page) 3. 09:23 AM - Re: Constructing an automatic RCA video camera feed splitter (Airdog77) 4. 11:55 AM - Re: Re: Constructing an automatic RCA video camera feed splitter (Paul A. Fisher) 5. 03:27 PM - Re: Re: Constructing an automatic RCA video camera feed splitter (Robert L. Nuckolls, III) 6. 03:40 PM - Re: Re: Constructing an automatic RCA video camera feed splitter (Robert L. Nuckolls, III) 7. 03:58 PM - Re: Re: Constructing an automatic RCA video camera feed splitter (Alec Myers) 8. 05:35 PM - Re: Constructing an automatic RCA video camera feed splitter (Eric Page) 9. 05:41 PM - Re: Constructing an automatic RCA video camera feed splitter (Eric Page) 10. 09:06 PM - Re: Re: Constructing an automatic RCA video camera feed splitter (Robert L. Nuckolls, III) 11. 09:14 PM - Re: Re: Constructing an automatic RCA video camera feed splitter (Robert L. Nuckolls, III) 12. 09:26 PM - Re: Re: Constructing an automatic RCA video camera feed splitter (Alec Myers) 13. 09:47 PM - Re: Re: Constructing an automatic RCA video camera feed splitter (Alec Myers) ________________________________ Message 1 _____________________________________ Time: 02:47:39 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: Constructing an automatic RCA video camera feed splitter At 11:28 PM 10/13/2017, you wrote: > >I know Wade's specific request for camera switching has been solved, >but it sounded like the sort of thing that might come up again so I >thought I'd take a stab at it. > >So... here's an alternative for switching cameras to a monitor or >EFIS input using a couple of voltage regulators and three ICs. All >components are through-hole. Everything on a single PCB, and no relays. > >Reference the attached schematic: > >An LM2931 5V linear regulator and a TC7660 charge pump provide +/-5V >rails to power the circuit. A 555 timer is configured in astable >mode to provide an output with adjustable period of about 3 to 10 >seconds. This output is fed to the clock input of a CD4022B octal >counter. The clock signal can be interrupted by a SP3T ON-ON-(ON) >switch to stop rotation of the cameras or advance them >manually. Outputs 1-3 of the counter are connected to the logic >inputs of an AD8184 4:1 video multiplexer such that they cause the >multiplexer to cycle through its four video inputs, connecting each >in turn to the output. RCA connectors provide four camera inputs >and one video output. > >LM2931AZ 5V Linear Regulator: http://preview.tinyurl.com/yakjxubl >TC7660CPA Inverting Charge Pump: http://preview.tinyurl.com/y7n7g6um >ICM7555IPAZ CMOS Timer: http://preview.tinyurl.com/ybrvnnq2 >CD4022BE Octal Counter: http://preview.tinyurl.com/ycjsa46w >AD8184ANZ 4:1 Video Multiplexer: http://preview.tinyurl.com/ybozz2nf >SP3T Toggle Switch: http://preview.tinyurl.com/ybpazcu5 > >Critiques? Suggestions? How about replacing the 555 and counter with a single uC. Paul Fisher can probably craft the software to emulate these two components to include the scan, step, rate and hold functions in one, 8-pin dip device and about 1/20th the hardware. Do you want to terminate unused outputs with dead shorts or 75 ohm resistors? RCA jacks are more robust than most miniature headphone jacks. Further, they're available to solder directly to an ECB. If termination of an unused output is necessary, a 75 ohm resistor can be installed in an RCA plug. Bob . . . ________________________________ Message 2 _____________________________________ Time: 06:03:20 AM PST US Subject: AeroElectric-List: Re: Constructing an automatic RCA video camera feed splitter From: "Eric Page" Eliminating the 16-DIP-packaged counter and most of the passives sounds fine to me. It will certainly shrink the PCB. If you can give me a pin-out for the uC you propose using, Ill amend the schematic. Ill need to know pin numbers for Vcc, Gnd, two outputs to the mux, how well read user input for run/hold and rate, and if an ICSP header is needed. Im guessing you propose the same (PIC12F683?) used for the recent prop current limiter... The AD8184 multiplexer has just one output, so I didnt figure a termination resistor was necessary. The connectors shown actually are RCA jacks, despite the CAD symbol looking like a headphone... http://preview.tinyurl.com/ycpmbhj5 They connect the AD8184 inputs to ground with an internal switch contact if no RCA is plugged in. Eric Read this topic online here: http://forums.matronics.com/viewtopic.php?p=473527#473527 ________________________________ Message 3 _____________________________________ Time: 09:23:59 AM PST US Subject: AeroElectric-List: Re: Constructing an automatic RCA video camera feed splitter From: "Airdog77" Eric, As an end user --I'll emphasize that aspect since you & Bob are speaking on a cosmic ethereal plane that this mortal struggles to follow [Wink] -- having another option is never bad. I really like the ON-ON-(ON) switch form factor for control. Simple and small, which is exactly what I need in a Long-EZ. Probably could be incorporated for most designs, but I'm glad you made note of it. Regards, Wade -------- Airdog Wade Parton Building Long-EZ 916WP www.longezpush.com Read this topic online here: http://forums.matronics.com/viewtopic.php?p=473536#473536 ________________________________ Message 4 _____________________________________ Time: 11:55:02 AM PST US Subject: Re: AeroElectric-List: Re: Constructing an automatic RCA video camera feed splitter From: "Paul A. Fisher" Since my name was mentioned, I'll weigh in. I'll be happy to modify the program Bob mentioned for this function, or more likely, just write a new one using elements of the one Bob mentioned. If I understand the AD8184 data sheet, we need to feed A0 and A1 one of four states - 00, 01, 10, and 11. That's pretty easy to do with just two pins. If we used the PIC12F683 (mostly because I'm familiar with it!!), we could do this: Pin 1 - Vdd Pin 2 - High order bit to AD8184 (connect to A1) Pin 3 - Low order bit to AD8184 (connect to A0) Pin 4 - not used Pin 5 - Run/Hold switch (pull low to hold) Pin 6 - Step switch (pull low to immediately switch to the next input) Pin 7 - Analog voltage (0-5V) to control the speed of switching in Run mode Pin 8 - Vss I think you could use the same switch (on-on-(on)) to ground pin 4 in position 2, and ground pin 6 in the momentary position. Analog voltage on pin 7 is similar to what you have on the proposed schematic. Is this what we are looking for? I'll let you and Bob decide on the hardware components necessary to make it all work, but the PIC software sounds pretty straight forward. Paul Fisher On 10/14/2017 8:00 AM, Eric Page wrote: > > Eliminating the 16-DIP-packaged counter and most of the passives sounds fine to me. It will certainly shrink the PCB. If you can give me a pin-out for the uC you propose using, Ill amend the schematic. Ill need to know pin numbers for Vcc, Gnd, two outputs to the mux, how well read user input for run/hold and rate, and if an ICSP header is needed. Im guessing you propose the same (PIC12F683?) used for the recent prop current limiter... > > The AD8184 multiplexer has just one output, so I didnt figure a termination resistor was necessary. The connectors shown actually are RCA jacks, despite the CAD symbol looking like a headphone... > > http://preview.tinyurl.com/ycpmbhj5 > > They connect the AD8184 inputs to ground with an internal switch contact if no RCA is plugged in. > > Eric > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=473527#473527 > > ________________________________ Message 5 _____________________________________ Time: 03:27:40 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: Constructing an automatic RCA video camera feed splitter At 08:00 AM 10/14/2017, you wrote: > >Eliminating the 16-DIP-packaged counter and most >of the passives sounds fine to me. It will >certainly shrink the PCB. If you can give me a >pin-out for the uC you propose using, I=99ll amend the schematic. See attached > I=99ll need to know pin numbers for Vcc, Gnd, > two outputs to the mux, how we=99ll read user > input for run/hold and rate, and if an ICSP > header is needed. I=99m guessing you propose > the same (PIC12F683?) used for the recent prop current limiter... Yeah . . . only 'case they're cheap and we got lots of them! Probably wouldn't fuss with ICSP, just put the chip in a socket. This lets a user drop a new chip into a fielded assembly should any future feature be desired/necessary. The sequencing software could be set up to default to either SCAN or STEP at power up. Your choice. If the default is STEP, then Channel A input is the first up. Momentary depression of the switch to STEP would advance to next channel in sequence. Momentary depression to SCAN would initiate steps through the four inputs at a rate commanded by the potentiometer. Setting a rate of say 3 to 10 seconds for zero to 5 volts seems a good starting point. I didn't suggest any DO-160 like protections for inputs to the command pins. If the switch is on the board it's not needed. If off the board, extending the lines in a shielded-twisted pair would offer plenty good prophylactics for our environment. >The AD8184 multiplexer has just one output, so I >didn=99t figure a termination resistor was >necessary. The connectors shown actually are >RCA jacks, despite the CAD symbol looking like a headphone... Aha! Been there . . . fiddled with several canned libraries for about an hour each before I dumped them all and crafted my own. >http://preview.tinyurl.com/ycpmbhj5 > >They connect the AD8184 inputs to ground with an >internal switch contact if no RCA is plugged in. Understand. I propose we make this another open source program like the wig-wag was . . . I'll be pleased to set up a folder to host all the work product. Bob . . . ________________________________ Message 6 _____________________________________ Time: 03:40:01 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: Constructing an automatic RCA video camera feed splitter At 01:50 PM 10/14/2017, you wrote: > >Since my name was mentioned, I'll weigh >in.=C2 I'll be happy to modify the program Bob >mentioned for this function, or more likely, >just write a new one using elements of the one Bob mentioned. > >If I understand the AD8184 data sheet, we need >to feed A0 and A1 one of four states - 00, 01, >10, and 11.=C2 That's pretty easy to do with just >two pins.=C2 If we used the PIC12F683 (mostly >because I'm familiar with it!!), we could do this: >Pin 1 - Vdd >Pin 2 - High order bit to AD8184 (connect to A1) >Pin 3 - Low order bit to AD8184 (connect to A0) >Pin 4 - not used >Pin 5 - Run/Hold switch (pull low to hold) >Pin 6 - Step switch (pull low to immediately switch to the next input) >Pin 7 - Analog voltage (0-5V) to control the speed of switching in Run mode >Pin 8 - Vss > >I think you could use the same switch >(on-on-(on)) to ground pin 4 in position 2, and >ground pin 6 in the momentary position.=C2 Analog >voltage on pin 7 is similar to what you have on the proposed schematic. > >Is this what we are looking for?=C2 I'll let you >and Bob decide on the hardware components >necessary to make it all work, but the PIC >software sounds pretty straight forward. > >Paul Fisher Our 'ships' passed in the night. I was going to suggest that you take the sketch I posted and adjust to what makes sense both from a software and layout perspective. Bob . . . ________________________________ Message 7 _____________________________________ Time: 03:58:48 PM PST US From: Alec Myers Subject: Re: AeroElectric-List: Re: Constructing an automatic RCA video camera feed splitter Bob Do you know how much extra work it takes to make a PIC meet DO-160? > On Oct 14, 2017, at 6:24 PM, Robert L. Nuckolls, III wrote: > > At 08:00 AM 10/14/2017, you wrote: >> >> Eliminating the 16-DIP-packaged counter and most of the passives sounds fine to me. It will certainly shrink the PCB. If you can give me a pin-out for the uC you propose using, I=C3=A2=C2=C2=99ll amend the schematic. > > See attached > >> I=C3=A2=C2=C2=99ll need to know pin numbers for Vcc, Gnd, two outputs to the mux, how we=C3=A2=C2=C2=99ll read user input for run/hold and rate, and if an ICSP header is needed. I=C3=A2=C2=C2=99m guessing you propose the same (PIC12F683?) used for the recent prop current limiter... > > Yeah . . . only 'case they're cheap and we got lots > of them! > > Probably wouldn't fuss with ICSP, just put the chip > in a socket. This lets a user drop a new chip > into a fielded assembly should any future feature be > desired/necessary. > > The sequencing software could be set up to default to > either SCAN or STEP at power up. Your choice. If the default > is STEP, then Channel A input is the first up. > > Momentary depression of the switch to STEP would advance > to next channel in sequence. Momentary depression to SCAN > would initiate steps through the four inputs at a rate > commanded by the potentiometer. Setting a rate of > say 3 to 10 seconds for zero to 5 volts seems a > good starting point. > > I didn't suggest any DO-160 like protections for > inputs to the command pins. If the switch is > on the board it's not needed. If off the board, > extending the lines in a shielded-twisted pair > would offer plenty good prophylactics for our > environment. > > >> The AD8184 multiplexer has just one output, so I didn=C3=A2=C2=C2=99 t figure a termination resistor was necessary. The connectors shown actually are RCA jacks, despite the CAD symbol looking like a headphone... > > Aha! Been there . . . fiddled with several > canned libraries for about an hour each > before I dumped them all and crafted my > own. > > >> http://preview.tinyurl.com/ycpmbhj5 >> >> They connect the AD8184 inputs to ground with an internal switch contact if no RCA is plugged in. > > Understand. > > I propose we make this another open source program like > the wig-wag was . . . I'll be pleased to set up a folder > to host all the work product. > > Bob . . . > >