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I'm thinking of making an IC FM radio, but I don't know where to start. I'd like AM too but it's not critical if it will be very complicated. Definitely need stereo. I really want search tuning and to be able to control it using a microcontroller (probably PIC24). The end goal really is to be able to press a button to search up and down for a station and store some presets. Anyone had any experience with FM radio ICs? I pretty much have none. Suggestions?
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Jan 26, 2009 00:51
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| # ¿ May 21, 2024 01:02 |
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Unfortunately they are sold out. They have a TEA5767 datasheet there, and I've been looking at TEA57xx chips. The TEA5777 does AM also but has been discontinued. They all look pretty tough to deal with. Now some really fun stuff. Before I looked into the new bigger chips, I was really looking at these: TDA1599 for FM and TDA1572 for AM (PDF datasheets). The 1599 has one audio out pin for MPX. So I'd get my stereo from that? Doesn't sound too bad, I think. They look fairly simple to deal with and build nice radio from. I probably couldn't prototype any of this on a breadboard, could I?
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Jan 26, 2009 03:47
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Did you look at neon sign transformers? 1.6kv might be a bit low for those though.
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Feb 13, 2009 06:50
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What's a fairly simple way to protect inputs in an auto application? I've seen some decent power supply circuits and automotive voltage regulators, but those applications were using a car's 12V power and isolating everything else. What if you wanted to read a switched battery or ignition signal as an input to a microcontroller?
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Jan 11, 2022 22:22
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That makes sense. I was over thinking it.
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Jan 12, 2022 00:45
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Many people use hearing aid batteries to power light meters in old cameras. The size and voltage are similar. They probably won't last any longer as I bet your new light meter batteries are the same zinc chemistry, but they are cheap.
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Sep 11, 2022 00:36
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You need something like an LR44 size but zinc-air 1.35V as a replacement. Look for hearing aid batteries. Sometimes an alkaline 1.5V will work depending on the camera.
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Sep 11, 2022 03:33
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CopperHound posted:Might mean underexposing a stop or two to compensate. Or was it overexposing? Probably depends on meter type. I meant that some cameras regulate the voltage so that alkaline batteries will still have correct light meter readings. These are usually later cameras, when the writing on the wall was clear that mercury batteries were going away manufacturers made their meters compatible with both battery chemistries. If the battery check reads correct with an alkaline, you're good to go. A higher voltage makes the meter read brighter, causing you to underexpose. So you over expose to compensate. The problem with alkaline batteries is that the voltage drops a bit when they discharge, so trying to compensate isn't always the same number of stops. Silver oxide batteries are 1.5V with a flatter voltage discharge curve, but the cost might be the same as the specialty batteries (but longer life, years vs months) and still compensating.
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Sep 14, 2022 02:38
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What are the good places to order PCBs from?
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Sep 27, 2022 00:19
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I don't know about service manuals, but a parts catalog might be the next closest thing. They have exploded diagrams with all the parts labelled with part numbers. I've ordered a few small things from https://www.uscamera.com before. Never a manual though so I don't know if you'd just be paying them for 
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Sep 29, 2022 01:33
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What is a good resource to learn buck, boost, buck-boost converter design? The first and last time I built a power supply was for a college class project and unfortunately all of that knowledge has been lost.
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Nov 28, 2022 15:35
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You probably don't need a continuous duty solenoid, and instead want your clutch position to be held by friction or a detent. You'll need either a bistable solenoid or two solenoids (one each to engage/disengage the clutch). You'll want that anyway to overcome the friction of the dogs when engaged, a de-energized solenoid won't give you that.
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Apr 5, 2023 20:12
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If he's adding or modifying a threading function on a lathe, a dog clutch is common to use because it's easy to keep the spindle and leadscrew in time.
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Apr 6, 2023 02:26
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AGM needs to charge at a lower voltage, especially as they age
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Apr 27, 2023 13:37
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How do you control the PWM for the fan? I've read they need 25kHz signal. I'd like to not have to change timers on an arduino to get it to work, but maybe that's the only practical option.
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Sep 4, 2023 01:04
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Every Christmas I vow to fix this, and then forget. Something triggered a memory so I'm posting while it's fresh in my mind. Mom has some old Hallmark Keepsake light and motion ornaments. These are the old style that run on 20 string bulbs. So 6V AC, I'm guessing around 200mA each. I think there are 6 ornaments total. This year Mom just got a new LED lit tree. I can't plug the ornaments into the tree. And I don't want to run another incandescent string in the tree. I'd like a completely separate power source for just the ornaments I can turn on and off separately. What's the best way to run these independently?
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Feb 8, 2024 00:21
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XHHW/XLPE/PEX/SGX is what we'll use for everything. Car wiring, house wiring, house plumbing. Just don't make it out of soybeans.
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Mar 4, 2024 15:04
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Rocko Bonaparte posted:Isn't there a kind of generational variation in the quality of capacitors? I remember it being a common enough this in the very late 90's into the early 2000's to have to resolder all the caps on a motherboard because they'd all swell and burst. That apparently resolved itself at some point? It was a whole thing https://en.wikipedia.org/wiki/Capacitor_plague
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Apr 6, 2024 18:29
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You don't need to terminate the stub you added. It's fine. You can leave it in place. Every car has a stub without a node connected: the diagnostic connector. It is supposed to be there. It doesn't cause problems. If you are asking about a terminator or terminating resistor: No, do not do that. The bus is already terminated, probably in the ECU and TPMS. Some definitions: Terminating resistor - 120 ohm resistor, one at each end of the bus Backbone, to suppress reflections Backbone - the longest length of the bus between two Nodes Node - ECU or device communicating with the bus Stub - length of wire between the Node and Backbone
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May 1, 2024 15:10
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| # ¿ May 21, 2024 01:02 |
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I think diagnostic connector on its own bus might be driven by a ISO 21434 thing. Fairly recent. So more accurately, almost every car in the past 30 years has a stub without a node connected on the main CAN databus. Cyber security is going to drive a lot more individual databuses and burying safety critical ones behind firewalls and gateways like you are seeing. Note: almost all my experience is on the SAE J1939 side and not directly with ISO 11898 CAN. J1939 is probably a bit more robust than ISO 11898 on the message side, but I think the physical layers are identical. CAN is extremely robust. Don't worry too much about screwing something up. The J1939 spec does not explicitly forbid empty nodes, but it does have one explicit mention of an empty node: the diagnostic connector. In practice, I've seen other empty nodes. A prime example would be a car with manual and automatic transmission options; one main harness part number would include an AT ECU stub that gets left empty on a manual. I've seen lots of crazy stuff too. Stubs should be under 3 meters, seen a lot over 3. One terminating resistor. Three terminating resistors. UNtwisted pair. Too many nodes. Stubs off of stubs. Things Just Work. Until they don't, then everything spits out dozens of fault codes. If you are not getting fault codes, let it run.
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May 2, 2024 02:38
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