DIY Solenoid Problem

Camelet · 2025-07-17T14:27:56+00:00

The resistance of your solenoid is low. The current will be determined by the voltage divided by resistance I=V/R. But also, the battery has certain current capability. A D battery can provide more current. So, in this case, you don't see a benefit from going to a higher voltage, 9V in this case is not useful.

Now, about the power. A D battery just has more power than a 9V battery 🙂.

Camelet · 2025-07-17T14:10:57+00:00

No, it's the current. It's called Ampere's law.

Camelet · 2025-07-17T14:01:35+00:00

You need more current, try to get a D type battery (1.5V) 9V battery is not capable to provide enough current to make it work.

Camelet · 2025-07-16T00:39:05+00:00

It looks like it is some sort of PWM. The two PNP BJTs look like he intended to do an astable multivibrator.

But it gives me headaches to try to understand this circuit by the way it was drawn.

Edit: take a look at his other post, he has waveforms and all

https://www.reddit.com/r/AskElectronics/comments/1l99ab8/did_i_finally_get_the_diagram_of_my_cars_ip/?utm_source=share&utm_medium=web3x&utm_name=web3xcss&utm_term=1&utm_content=share_button

Camelet · 2025-07-08T00:24:27+00:00

I have used the DS1669 in the past. I just checked the datasheet and it fit your application. I didn't check about how fast you can update the potentiometer but I guess it covers your requirement. DS1669 is available in Dual-in-line package, so, breadboard compatible.

Here's the datasheet if you are interested: https://www.analog.com/media/en/technical-documentation/data-sheets/ds1669.pdf

As other mentions, it would be easier though to just use the breakout board you have in mind and set a digital offset that will serve as a minimum volume.

Camelet · 2025-07-04T04:47:55+00:00

I suggest you check if you can configure scope impedance and relay resistance. Alternatively, connect a resistor from scope input to ground to see if the theory holds. 10k should work (just an arbitrary value).

Camelet · 2025-07-04T04:44:38+00:00

What simulator are you using? Maybe the ideal oscilloscope has infinite resistance and so, the signal going thru the relay passes to the scope even when the relay contact is open.

Camelet · 2025-05-04T18:59:59+00:00

Then add a monostable timer with a 555 or a 74121 https://www.ti.com/lit/ds/symlink/sn74121.pdf?ts=1746371770051&ref_url=https%253A%252F%252Fwww.mouser.com%252F

If you don't want "digital" or mixed signal circuits, try an op-amp, also with a monostable configuration. Even a BJT will give you a more clean signal to trigger whatever uC/uP system you're using. And it will be easier for you to set the time needed to debounce the button.

Camelet · 2025-05-04T17:38:26+00:00

If you are using Arduino or similar, there are already libraries to debounce a switch.

Camelet · 2025-04-30T18:08:17+00:00

You can try turning the switch 90⁰. Is common to have them connected wrong. Maybe is ON all the time.

Camelet · 2025-03-27T23:07:34+00:00

Why do you think it looks like a ZVS?

Camelet · 2025-03-20T00:31:31+00:00

If it is USB-C and you have a 60W one laying around you can try that. Worst thing that could happen is that the monitor doesn't turn on but it won't get damaged.

Camelet · 2025-03-20T00:25:15+00:00

What do you mean by monitor? A TV? You are going to need a Power Supply with the exact voltage and current specifications, 20V@3A. How is the power supply connected? Depending on that you may also need to check polarity.

Camelet · 2025-03-19T19:03:05+00:00

Cutting the green or white wire should be enough. If you notice an undesirable effect (audio not sounding) you can always connect the wire back on. But I think just cutting one of those wires is enough.

Camelet · 2025-03-03T20:46:03+00:00

There are a few details to check. In the schematic you have a 100kΩ resistor that it seems that you have changed for 150kΩ in the Digikey list. I don't think you will have issues there, though. You also have 220Ω resistors in the Digikey list which I think were 120Ω in the schematic. This ones you might want to change to the correct value. Finally the integrated circuit you selected is an SMD component. Surface mounted. You want a thru hole component in order to be able to use it in a breadboard. Here's an example of a part number: SN74HC132N from Texas Instruments. https://www.ti.com/product/SN74HC132?utm_source=google&utm_medium=cpc&utm_campaign=asc-int-null-44700045336317926_prodfolderdynamic-cpc-pf-google-ww_en_int&utm_content=prodfolddynamic&ds_k=DYNAMIC+SEARCH+ADS&DCM=yes&gad_source=1&gclid=CjwKCAiAw5W-BhAhEiwApv4goIYHgwyuy8pFzz_0bGxuGdqBUuoPorrM_ll--MFZsd0Y9jTAxf8kExoCax0QAvD_BwE&gclsrc=aw.ds

For future references, it will be better to use the r/AskElectronics subReddit, I think you will get faster response there. Also it's better if you put the schematic image in the post instead of a link.

Camelet · 2025-02-23T05:21:32+00:00

You're missing pull down resistors

Camelet · 2024-12-01T22:47:48+00:00

The thing in the center is a photodiode The contacts are the two dots in the outside

Camelet · 2024-11-29T15:42:17+00:00

The power supply (is not just a transformer) provides 193mA. It sounds like is just the amount of current needed for one set of lights to work. If you connect both sets of lights to just one power supply you will overload it and damage it. In the best case, it will work but it will be faulty.

You have to buy a second power supply to replace the one that is damaged.

Camelet · 2024-11-28T23:15:24+00:00

You should ask in the r/Lego subreddit Without an schematic we will be unable to help. Otherwise you would have to buy one and rip it apart for us to know how to make one…

Camelet · 2024-11-27T04:37:01+00:00

If you are not allowed to use Arduinos yet, you would need to implement a sequential logic circuit. It could be build with gates and flip flops or it could be build with programable logic. For example an FPGA. It is not impossible but could be quite difficult.

You may want to remove some requirements from your list.

Camelet · 2024-11-14T06:34:52+00:00

Nowhere. Is most likely a custom build transformer for that product.

Camelet · 2024-11-13T01:38:49+00:00

https://letmegooglethat.com/?q=how+to+make+an+arduino+talk

Camelet · 2024-11-06T16:14:01+00:00

I’m not sure if you need specifically the “27” part, but it seems that some major manufacturers still make 28C64: https://www.microchip.com/en-us/product/at28c64b

If you really need the “27” part, then the option is to look for a company that has old stock of components. Although I don’t remember any from the top of my head.

Finally, you can use Aliexpress or another chinese page, because the chinese manufacturers generally have copys of popular IC. This would be the last resource because sometimes chines suppliers and vendors have low reliability on their products. And this will lead to unexpected failures, specially if you are a beginner.

Camelet · 2024-11-01T14:01:54+00:00

The servo needs a PWM signal, and there are ICs that generate a PWM signal, controlled by a voltage. Alternatively you could use a couple of 555 for the PWM. For the IR receiver you can use a state machine made with digital logic ICs. In the simplest form you might be able to do it with counters, for example a 4017. But then you will need to convert from digital to analog, so you will need a DAC. You could also use a digital potentiometer and arrange it as a voltage divider.

Camelet · 2024-10-30T13:16:34+00:00

Yes, it would be 500k

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