Low cost nanovolt switch / scanner
Added 2024-05-16 14:11:48 +0000 UTC... made from rotary switches? It looks promising, but it's not yet reliable enough
Comments
Hello, I've been mulling over a similar problem with connecting some higher voltage testing equipment. I'm thinking I can adapt your strategy with a couple modifications for the higher voltage requirements. My tests measure in the picoamps so the power consumed is similar and the sensitivity requires a similar mechanical solution. I'm new to this Pateron thing, do you have a section for the gerber files and 3d models that I can use? Thanks!
Max Teicheira
2024-05-27 08:03:14 +0000 UTCThanks! I will check it out. Your channel actually started my descent down this rabbit hole!
Curtis Seizert
2024-05-21 18:42:52 +0000 UTCoooh I've seen your awesome nanovoltmeter on github, but never knew you were here! please consider joining the discord server, we have a special #nuts channel that needs some action 😁
Marco Reps
2024-05-21 17:51:57 +0000 UTCI used cheap Omron G6KU-2G-Y-DC5 latching relays for the front end switches in a DIY nanovoltmeter project, and a 10 ms pulse on the coil only causes the offset to jump by <5 nV. This could probably be further improved by using high sensitivity Panasonic TXS2 relays shortening the pulse length, and reducing the coil excitation voltage. Did you compare the performance of this solution to the nanovolt relay card you mentioned in a previous video?
Curtis Seizert
2024-05-21 17:41:12 +0000 UTCAfter seeing the video a second time on YT, I just had a nanovolt scanner epiphany: why not use a linear instead of a rotary drive? Slide a wiper board over an extendable set of aluminium core contact boards, with 4 analog and 6-8 encoder lanes, for absolute and repeatable positioning? One could use 2 "sleds" for matrix switching (or 2 separate drives, of course). And the best part: I have just the defective photo flatbed SCANNER (get it?!!?) with basically all of the necessary electro-mechanical parts... I'm actually excited! : )
Michael Hagemann
2024-05-21 14:26:28 +0000 UTCMaybe it's easier to include the motors within the enclosure and use gas-tight wire interfaces instead of gas-tight mechanical interfaces?
Nikolaus Juch
2024-05-20 17:56:10 +0000 UTCthey are a bit tricky to import https://item.taobao.com/item.htm?id=40823926055
Marco Reps
2024-05-18 07:17:10 +0000 UTCDid you consider using a custom built matrix switch with solenoid operated contacts. You could use a pcd for the fixed copper contacts and copper moving contacts mounted on the board and actuated by plastic push rods. The 'switching plane' could therefore be shielded from the actuators. Like your rotary switch system, this is not a 5 minute project to implement but it could work. Just a thought!
Max Pearce
2024-05-18 00:16:11 +0000 UTCWho is the supplier of the solid copper 4mm binding posts?
Max Pearce
2024-05-17 23:56:02 +0000 UTCI have somewhere a stepper for a pick and place machine. It has a hollow shaft so you could add a small solenoid to lift the contact arm, move it and put it down again.
Kevin W
2024-05-17 14:14:46 +0000 UTCReadily fixed in the next iteration!
Christopher Arena
2024-05-16 20:06:06 +0000 UTCOh what an entertaining problem to have! Please consider joining the discord server, we have many 7081 experts there
Marco Reps
2024-05-16 19:36:59 +0000 UTCThe isolated contact pair is actually already there, but the size and position I chose make them unreliable :(
Marco Reps
2024-05-16 19:36:24 +0000 UTCWhat a crazy plan, I love it! Maybe a hermetically sealed switch with a one-time filling and magnetically coupled motor?
Marco Reps
2024-05-16 19:35:28 +0000 UTCMaybe a few ruined Muirhead or GR resistance decades would provide switches with similar qualities to the one pure copper switch that you had donated. They would probably be more consistent and durable than the 3D printed versions.
Michael Johnson
2024-05-16 14:57:07 +0000 UTCVery interesting idea! I am currently having fun with a similar problem. The 1N829 diode in my Solartron 7081 turned out to be very sick, exhibiting 4ppm of popcorn noise. As I wanted to keep the meter as original as possible, I'm currently going through the long and painful selection process to find one golden 1N829 out of six new old stock candidates. The arrival of springtime and greater temperature variations has buried what I'm looking for under the tempco of my measurement device and the relay card in my 3488A multiplexer. I'm almost thinking about building a huge thermal chamber like the one TiN made, but I simply don't have the space for it.
Michael Johnson
2024-05-16 14:54:12 +0000 UTCIf you had a source of some "inert" gas -- maybe N2 -- you could slowly leak that gas into the box to avoid oxidation effects? a cylinder of N2 could last a long time at low flow rates.
Christopher Arena
2024-05-16 14:48:38 +0000 UTCYou could include one position -- one isolated contact pair -- to signal the home position. If the controller understood something about the switching taking place, it could reposition one switch in the chain to isolate the power so that a short circuit couldn't occur. The hardware should want to protect itself or understand how to protect itself to avoid short circuits. A simple matter of software!!!
Christopher Arena
2024-05-16 14:45:34 +0000 UTC
