02-25-2020, 09:47 PM
Look on my project page.. I already done this and works fine
02-25-2020, 09:47 PM
Look on my project page.. I already done this and works fine
02-27-2020, 09:34 PM
(02-24-2020, 11:51 PM)InOverMyHead Wrote: Well, Hella is the name brand. There are cheaper alternatives. I'm amused I didn't just do this... bought 2 different random timer modules from ebay/amazon/aliexpress ... coulda just bought that. LOL... still might.... I love getting tripli-cates of things for no reason. GFunkbus76 - Working on dual screen setup to run 1976 bus AV and dash... eventually. - Work in long-term progress lol YouTube Channel for some related videos
02-28-2020, 05:12 AM
Haha just like me. I have only one raspberry headunit setup, but I have 3 different shutdown setups. One in my car and two in the drawer just becouse. Stupid right
Raspberry Pi 4b-4gb / Official 7" touchscreen / OAP 5.0 / Honor 8x (AndroidAuto 5.) / USB sound card / USB microphone
02-28-2020, 07:27 PM
(This post was last modified: 02-28-2020, 07:29 PM by InOverMyHead.)
Yeah, I'm all about simple solutions that are "repairable" with common parts. If the relay fails, I can put in a standard STDP relay (a handful of spares will live in the vehicle already) to boot it, and just manually shut it down in a pinch. I just ordered 3, so I'll let you know how it goes once I piece something together.
02-28-2020, 11:45 PM
(02-28-2020, 07:27 PM)InOverMyHead Wrote: Yeah, I'm all about simple solutions that are "repairable" with common parts. If the relay fails, I can put in a standard STDP relay (a handful of spares will live in the vehicle already) to boot it, and just manually shut it down in a pinch. I just ordered 3, so I'll let you know how it goes once I piece something together. Please do let us know, sounds like we're all in the same boat, I have about 3 timer setups laying about now as well, haha.
03-03-2020, 06:11 AM
I ordered the ten minute timer from AliExpress. Couldn't figure out a recent Amazon one, so this should be more straightforward lol... Will update.
GFunkbus76 - Working on dual screen setup to run 1976 bus AV and dash... eventually. - Work in long-term progress lol YouTube Channel for some related videos
03-03-2020, 03:31 PM
Great, im looking for a simpler solution as well. even if it costs more.
03-20-2020, 09:33 PM
Hello, new member here. I still have yet to purchase my license for OAP, I'm still waiting for some parts from China, RTC, DS18B20, Timer Relay, UGREEN USB soundcard, CSR Bluetooth module. I already have the Pi 4 2GB, the official Touchscreen, GPS Module, and a TDA7850 4 Channel Amp. I also have a double DIN case and a Pi Camera. I plan on picking up an HDMI Camera extension soon.
Looking at the diagram for the safe shutdown at the start of this thread, and reading through, I have a couple hardware suggestions. 1. If a person wants to use the 30-40A rated 12V automotive relay, using pins 30 and 87a, I recommend at minimum putting a snubber diode like a 1N4001 across the coil of the relay, reverse biased, (putting the stripe of the diode to the +12V side). This will prevent electrical spikes from entering the system when the relay is de-energized. I can answer questions on the theory and provide examples of bad things happening without the snubber if asked. Also realize that you are using a relay rated at 30-40A to control a very small milliamp signal into the GPIO. I saw one place that the pull-up resistor is something on the order of 60KΩ. At 3.3V, and a 60KΩ resistor, that makes the current about 55uA. I know that some relays in Industrial Automation use the Amperage and Voltage passing through the relay contact to keep the contacts clean and non-oxidized. Running a small signal through these relays could cause a failure of the contacts in the long term, as the oxidation does not get cleaned off. If you're going to be using a small signal, they make bifurcated relays that are designed for the small signals. Or I think those relays are purged and sealed from oxygen to prevent oxidation. But who knows how long it would take for one of the automotive relays to fail. It might be years. 2. One post I saw said someone accidentally bought a relay that only had a Normally Open contact. In that respect, the script was modified to accept the inverted signal. Since that worked, why not use an opto-isolator to drive the GPIO pins? With the proper resistor on the primary side of the opto, tied to the ignition, when the ignition is on, it will pull the GPIO pin to Common. No big mechanical relay needed. I've used a Vishay 617A in another project and they work well. With a 12-14.5VDC input, and a 1500Ω to 2200Ω resistor, that should provide a good input into the Pi. Hope this helps somebody, or at least gives them some ideas.
04-19-2020, 09:39 PM
(This post was last modified: 04-19-2020, 10:04 PM by frankpintosr.)
Hi All, well I have finally attempted to build this circuit. I was really having a difficult time ensuring the correct connections. I have a 12v 2a AC to DC power supply that I am using to power the circuit for testing outside the car. I simply cut the end off the cord and connected positive and negative wires to a bus bar. To simulate switched power (ACC), I have a jumper wire from the constant 12v to another terminal.
Now, on to troubleshooting to find what I did incorrectly. First issue - When I apply power to the circuit, without connecting switched power, the transformer provides correct 12v to the circuit. Unfortunately, the circuit doesn't power on with just 12v constant. Next step, I connect the ACC jumper and the transformer shuts off. It must have some protection circuit. I am attaching several pictures. Red wire is constant 12v. White wire is switched 12v. Black wire is ground. Can someone please help me with this?
04-20-2020, 03:36 PM
(This post was last modified: 04-20-2020, 03:44 PM by jhornbr225.)
(04-19-2020, 09:39 PM)frankpintosr Wrote: Hi All, well I have finally attempted to build this circuit. I was really having a difficult time ensuring the correct connections. I have a 12v 2a AC to DC power supply that I am using to power the circuit for testing outside the car. I simply cut the end off the cord and connected positive and negative wires to a bus bar. To simulate switched power (ACC), I have a jumper wire from the constant 12v to another terminal.Looking at the pictures, you might have the timer circuit board upside down as referenced in the original post on this thread. I believe that your incoming power should go to the DC+ and DC- respectively. I believe on your board the CH1 might be the trigger. I conclude this because clearly the other side of the board has NO, COM, and NC. And I know on that side of the board you only need connections in the NO and COM. So I believe in your case: DC+ is +12V In DC- is GND CH1 is Trigger Other side of board: COM is +12V In (Car battery) NO is +12V Out Take all your wires out of the timer board, rotate it so that the NC, COM, and NO are on the right hand side, and the buttons are at the top. Then install your wires following the picture on the initial post. Be cautious of the input side. The terminals are not in the same order as yours. I know the original post shows the buttons on the bottom, but you can't see the board labels in the picture of the actual board. The relay on the board is on the output side, both on that board and yours. Your transformer is shutting down probably because you are shorting it from + to -. Good luck! |
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