Redhorse Cafe -- the Food Truck

[Broken Arrow]

As for the breakfast, I do my very best. Ok, eggs are plenty.

After the 24th PT session you got used to it and it will go better.

Hold out!

[OLChemist]

*Rose retreats to the table by the generator.*

Oh BA, the LM741 was just what I needed. It works great as long as the pre-amp for the pyro is on and everything is warmed up. But if the pyro or pre-amp power is dropped, like what happens when my colleagues ignore then instructions about how to turn on the test equipment the signal will still run to negative rail. Bad news for the downstream ADC.

I tried ye ol' standard pair of Schottky diodes -- the circuit that is in every white paper AD, TI or Maxim has ever put out on protecting ADC inputs. It's not adequate. I think pair of the problem is I used the diodes I could find in the shop - 1N5711's. Fortunately I ran my output into a scope rather than the microcontroller. I think part of the problem is that I don't have the right diodes. I've ordered a bunch of BAT42's and BAT43's. But, I don't think it is going to be enough to handle the transients that occur when things aren't powered up right.

I think I'm going use a relay to switch on the input. The amp power supplies both have 5V. I can have the microcontroller monitor for both of those to be on and then switch the signal to the ADC only when both supplies are on and the program is ready to acquire data. I think if I use the diodes and an low-pass RC filter I should be able to suppress any ringing that goes negative.

This is getting beyond my learned in the gutter electronics skills.

[Broken Arrow]

*Rose retreats to the table by the generator.*

Oh BA, the LM741 was just what I needed. It works great as long as the pre-amp for the pyro is on and everything is warmed up. But if the pyro or pre-amp power is dropped, like what happens when my colleagues ignore then instructions about how to turn on the test equipment the signal will still run to negative rail. Bad news for the downstream ADC.

I think I'm going use a relay to switch on the input. The amp power supplies both have 5V. I can have the microcontroller monitor for both of those to be on and then switch the signal to the ADC only when both supplies are on and the program is ready to acquire data. I think if I use the diodes and an low-pass RC filter I should be able to suppress any ringing that goes negative.

This is getting beyond my learned in the gutter electronics skills.

May be instead of a relay a switch, perhaps something like that MAX322

Controlling if the other amps are up and than connect is in view of your colleagues acting the best you can do I think.

And your in the gutter electronics is far better in comparison to what my students learn today. Hey, you are really good.

[OLChemist]

Chuy, some ramen and side of painkillers.

I hope this PT helps. I had to lock myself in my office for 30mins after climbing the steps this morning. I was in tears by the time I got halfway up. I'm building up to go down the hall and wire up the stepper motors on a pitch and yaw stage, and try my new diodes.

I want my morning back. I bought a couple breakout boards for a 16bit analog to digital converter for the Raspberry Pi. I have had trouble finding any in stock -- dang chip shortages. It turns out that there are isa a batch of counterfeit chips that are the 12 bit version of a 16 bit chip with the number for the 16 bit printed on them. The problem is when you read the conversion register on the chip the 4 least significant bits are zero. The noise is in bit 5. Rather than <0.2mV resolution I have 3mV.

[wardancer]

You guys are talkin' "picnic table" again ! I can't understand a word yer sayin' ! LOL

[wardancer]

I've never had raspberry pie !LMAO I prefer Apple !

[OLChemist]

LOL. I prefer Apple too. I already have this mostly running on a mac, LOL. But the powers that be want me to play with the cool kids and their Raspberry Pi's. So, I have to learn Python and Circuit Python and do this again.

[Broken Arrow]

Chuy, some ramen and side of painkillers.

I hope this PT helps.

I want my morning back. I bought a couple breakout boards for a 16bit analog to digital converter for the Raspberry Pi. I have had trouble finding any in stock -- dang chip shortages. It turns out that there are isa a batch of counterfeit chips that are the 12 bit version of a 16 bit chip with the number for the 16 bit printed on them. The problem is when you read the conversion register on the chip the 4 least significant bits are zero. The noise is in bit 5. Rather than <0.2mV resolution I have 3mV.

OK what painkillers do you need? PT may help but it will take time and that isn't easily forcasted.

Not good. Don't know if it is possible with the AD you have and the change ratio of the signal which is to be converted has to be slow enough. You could do a double conversion as with the AD of the MC 80515. First determine in what quarter of the voltage range you are with the full voltage range, than change the comparison voltage to that quarter and convert again. With 12 bit in this way you come close to a 13,5 bit bit measure if your full voltage range is 12 V. Still not 16 bit but better than 12 bit. Can the Voltage range be converted be reduced?

WD you will find that the raspberry pie is indigestible and will taste like plastic and worse. Most probably bad for the teeth too.

I vote for the apple pie.

[OLChemist]

Thanks BA. Sounds like a lot of work:) Too much work for me. I'd have to order the parts and probably send them out to a company to mount them on DIP breakouts, since we're not equipped to deal with surface mount parts. Ordering electronics components right now is fraught. We're having all kinds of shortages and delays due to supply chain issues and labor shortages.

I have returned most of the boards with the counterfeit chips, and have ordered from a vendor who is aware of the problem and says their boards have 16 bit chips. I can do my initial setup and coding with the 12bit. The 16-bit boards will be here Tues.

[OLChemist]

Tuesday

<iframe width="560" height="315" src="https://www.youtube.com/embed/5ihsG301xpc" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>

[Broken Arrow]

Tuesday, good guess.

LOL.

The twice measuring if it is not ready wired like in the 80515, f... s... That will take time because it has to be thought about how to do it and get stable precision and to relaize the comparison voltages.

I bet Tuesday delivery is more probable than doing it until Tuesday myself or yourself. And you have more recent practical training than I have. I have become a paper pusher and theorist. Oh and I may be great administrative officer. My archives floor was flooded. Only three years of duplicate final certificates are ruined. (Somewhere between 3000 to 4500)

[wardancer]

LOL. I prefer Apple too. I already have this mostly running on a mac, LOL. But the powers that be want me to play with the cool kids and their Raspberry Pi's. So, I have to learn Python and Circuit Python and do this again.

mac ? Mac and cheese ? LOL
Pythons are big azz snakes and I don't like snakes !
If you play in raspberry pie you'll have reddish purplish fingers !

[OLChemist]

Chuy, something in chocolate, please. And a shopping bag to put over my head.


I am currently having to use a cane with my hips. Thus carrying things back and forth between the electronics area in my office and the optics lab has been tricky. This week, I've been going back a forth a lot with various bits and bobs. To free my hand for the cane, I've been draping cables around my neck.

I just got called into a last minute Zoom meeting with a customer. Sad to say I was 15 minutes in, before I realized I was still wearing a nerd neck tie made of three BNC cables with tees, a USB cable, two oscilloscope probes, and an antique null modem cable.

As always, I'm ever the fashion plate, lol.

[OLChemist]

mac ? Mac and cheese ? Lol
pythons are big azz snakes and i don't like snakes !
If you play in raspberry pie you'll have reddish purplish fingers !

lmao

[wardancer]

I already miss the like button !