Recent Posts

11

Projects, Designs, and Technical Stuff / Re: (Yet Another) DIY Multislope ADC

« Last post by Kleinstein on Today at 06:32:00 am »

Both the negative and positive ref. counts are included in the result. This applies to both cases with the positive and negative charge to start with. So not special handling needed for cases when the short pulse at the end can have slightly different length.

The problem is not the cases with a short positive or short negative pulse . There is anyway also the case near zero resudual charge when both pulses are short.

The slight complication with a rundown come from a not perfect balance between the positive and negative reference. For the run-up part either the positive or negative reference is active. So the relevant scale factor is the difference between the 2 run-up step cases and thus the difference (including the sign) positive an negative reference currents. For the rundown part there are 3 possile states with positive, negative or no active reference. One can write the positive/negative ref. as:   +-0.5 * (pos-neg) + 0.5 (pos+neg) . The main part is still from the difference, like in the run-up, but there is an additional correction term from the sum of the references. With ideal symmetry this would be zero, but the circuit is usually not ideal and thus the extra small correction term with the sum of the reference currents. Ideally one would measure it in an extra calibration procedure (could be only once at the initial calibration) and include the correction term. The alternative would be highly accurate resistors (e.g. 0.05% range).

The   - 2*RDN + RDNP   from is for perfect symmetry. With the correction for possible asymmetry there is an additional small term proportional to RDNP. The post aux_adc would than add another term for additional resolution with a separate cal factor.

12

Projects, Designs, and Technical Stuff / Re: What is the 'go-to' MQTT broker software for local home setup

« Last post by mianos on Today at 06:30:35 am »

I have run Mosquitto at home for years.

Nothing exciting, just faultlessly working.

I have about 30 devices at the moment and also use Node-red with it. Half of the devices are my own software and publish to mqtt.

Not all wifi, a bunch of zigbee, 433Mhz RF, infra-red and bluetooth all bridged into mqtt.

I run it in an LXD container on my N100, but I'm sure it'll run great on a newish raspberrypi.

I'd just install it and use the command line "mosquitto_sub -h localhost <TOPIC>' and 'mosquitto_pub -h localhost <TOPIC>' to start learning it.

chat gpt knows it pretty well if you want help.

13

Test Equipment / Re: Fun With Low Leakage/Bias Current: Femtompere, Electrometer, Keithley 617

« Last post by BD1QMP on Today at 06:29:58 am »

when I was testing it, I put a copper foil on it.

14

Power/Renewable Energy/EV's / Re: Aussie Fast Charger Company Tritium Goes Bust

« Last post by uer166 on Today at 06:21:09 am »

I would expect the Tritium products to be decent, reliable and higher tech designs.

Eehhh as someone who's seen the internals of one I'd slightly disagree. It's a very messy design with a clear lack of integration/vision. Wires everywhere, myriad of interconnects, and a general sub-par design of the assembly. Unimpressive specs, and complete lack of network security at all as well.

They were/are stuck about 15+ years in the past and for whatever reason did not or could not innovate.

If you want reliable and optimal power electronics you'd go with Tesla power electronics.

15

Other Equipment & Products / Re: Dymo 550 Thermal Printer DRM Hacking

« Last post by RethoricalCheese on Today at 06:20:28 am »

Use S0722370 instead of 30252. Both are same size, right?

I found that those short model number variants did not work for me but those starting with S do work.

16

Test Equipment / Re: SDS800X HD Wanted Features

« Last post by eTobey on Today at 06:19:23 am »

Modify the rules for adding wanted features list. "Wanted features" need the "Say Thanks  " of two other people besides yourself, so you need to describe usage scenarios clearly so that you can get the approval of others.

Who is reading all the posts when there is so much unrelated text? Good features might be missed in between.

17

General Technical Chat / Re: Russia and China to Build a Nuclear Plant on the Moon.

« Last post by Andy Chee on Today at 06:19:00 am »

high power reactor cooling in space will be biggest challenge because there is no way to dissipate excess heat

Sure there is.  The same way the sun sends its heat to earth.  Radiation.

Heat can transfer in four ways; phase change, conduction, convection, and radiation.

Whether a high powered nuclear reactor can be cooled via radiation alone, now that's an engineering challenge.

18

Metrology / Re: Philips PT 2248 Ref. Unit, any Manuals?

« Last post by goaty on Today at 06:13:42 am »

Got one just now. Need to carefully try to start it up as its 220V.
Anyone knows what it was for ?
Interresting bit of kit.

19

Test Equipment / Re: Hacking the Rigol DHO800/900 Scope

« Last post by AceyTech on Today at 06:02:29 am »

I'm making changes directly to the latest Sparrow.apk version.

Awesome!  Very cool.  I was away for a bit, so please forgive my naive Q's;
Is your modified app fully functioning when installed? i.e., able to save screenshots, etc... 
Is it easy enough to try your mods by doing a simple remove/install of the APK?

20

Test Equipment / Re: Micsig Current Probe CP2100A/B Tests and Comparing

« Last post by ceut on Today at 06:01:16 am »

Hello,
I have received my Misig CP2100B.
It is really a great current probe 

Some photos, because it seems to be a new 2024 batch:
- wire is not a big grey for the clamp, but thin soft black
- piece of rubber to hold the cable
- the in/out of the wires are rigid plastic part 

I have also checked the power consumption on RD6006P with its great calibration  : it is really low  0.044mA
And it seems the relay may be a 2 coil-latching one, because there is only a very short peak of current when switching at about 0.15A, then come back to 0.044mA