Arduino + MCP9600 + thermocouple help needed

Mar 18, 2024 Last reply: 2 years ago 43 Replies
J

Yes, it's a good feature of battery-powered small cheap scopes that they allow ungrounded operation. As you note, some of them can't capture I2C, which I didn't think about WRT the cheap scope I linked. It does 250 KHz, not good enough for `Fast Mode` I2C at 400 KHz, let alone the 3.4 MHz and 5 MHz versions of I2C.

--------------------------- He could setClock() low enough for it. That scope would be fast enough for most of my hobby use, though I was spoiled by the $20,000 scope I ordered for digital radio data speeds. The company had one that went to 70GHz, with liquid helium cooled Josephson junction input amplifiers. They used it to develop military satellite uplinks, then parked it and its Dewar in the back of my lab. Since it lacked storage and even a trigger it wasn't generally useful. Mostly I used an HP8753 vector network analyzer instead of a scope above 1GHz.

Digital radio tech has made them very affordable:

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Unlike many other communications protocols I2C doesn't depend on timing accuracy and the actual speed can be whatever suits the controller hardware and software, without bothering with timing. It is event-driven, the rising SCL clock edge indicates when to put SDA data on the bus, the falling edge of SCL when to read it, a microSecond or a day later. A program may impose an arbitrary timeout to detect a bad connection. In practice the upper speed limit depends on how quickly the pullup resistors can charge the capacitance of the interconnecting wires, which is why their length is limited.
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J

Yes, it's a good feature of battery-powered small cheap scopes that they allow ungrounded operation. As you note, some of them can't capture I2C, which I didn't think about WRT the cheap scope I linked. It does 250 KHz, not good enough for `Fast Mode` I2C at 400 KHz, let alone the 3.4 MHz and 5 MHz versions of I2C.

------------------------------------ Amazon shows other low cost scopes with 2 channels and higher bandwidth. Their operation is entirely by menu choices which is initially confusing for me, a user since the big vacuum tube Tektronix era, let alone a newbie to scope use with only a vaguely worded instruction sheet and no other owners to ask for help.

I use Amazon as an aggregator of similar items, for an overview of what's available with user reviews, not necessarily as the seller I buy from.

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R

Lot to learn... Mercifully with the current price of devices, can get on with applications and learn by trial-and-error.

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L
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I do this with almost everything new[1] I buy nowadays. Helps to determine a fair price and most importantly if a product has some serious defects and best to avoid...

[1] A product new to me, that I haven't bought before or investigated.
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