Frequency Specific Microcurrent Need Help in Developing this Device - Page 1
Forum section: electronics / projects

author: bmj123
author_rank: Newbie
timestamp: September 27, 2020, 10:06:55 am
content: HiI am a physical therapist and using microcurrent devices. Can you teach me how can I measure output current in these microcurrent deviceshttps://www.inspirstar.com/products/our-products/is02pro-stimulator/Please guide me on how can we measure output which ranges from 10- 400micro A.Also, they have two frequency F1 and F2 each one gives an output from 0.1 to 999hz.I am sending you an inside circuit design as well.regardsBal Mukund Jha

author: Marco
author_rank: Super Contributor
timestamp: September 27, 2020, 02:58:53 pm
content: A µCurrent GOLD and a battery oscilloscope should work just fine.

author: rstofer
author_rank: Super Contributor
timestamp: September 27, 2020, 06:31:39 pm
content: https://www.eevblog.com/product/ucurrentgold/You can also search the forum and perhaps Google for uCurrentGoldThis device is NOT rated for medical applications. You should really search for a unit that is rated (FDA Approved in US) if there is any chance the current is measured while connected to a patient.

author: bmj123
author_rank: Newbie
timestamp: February 04, 2022, 05:44:12 pm
content: thanks any update on this

author: bmj123
author_rank: Newbie
timestamp: February 04, 2022, 05:45:03 pm
content: someone who can help me in developing this device at commercial level.

author: coppercone2
author_rank: Super Contributor
timestamp: February 04, 2022, 07:00:03 pm
content: uCurrent or a current amplifier (usually old) are the off the shelf items that will work on thisI would recommend the uCurrent.. that is the best value

author: bmj123
author_rank: Newbie
timestamp: February 05, 2022, 01:54:36 am
content: Hi, thanks for your reply can you assist me in Developing a Programmable microcurrent device. I can pay consultancy fees. As I am new in this field.I have no idea how to progress.I shall be very thankful to you.My email is physiofirst@gmail.com

author: ilmguy
author_rank: Newbie
timestamp: February 16, 2022, 03:18:50 am
content: Hello Bal,Have you had any success on getting help on this project yet?If not, if you can send me some clear High Def photos both FRONT and BACK of both PCB boards so that I can see the chip names and any SMD part #s, etc, and where the traces/connections lead to I may be able to assist and draw up a schematic of sorts for you if I can gather all the info. Multiple photos will be ok as well and I can connect on my side so long that I can see all the parts and know where everything connects clearly.Is this from the "Professional" Version per the website?Are you trying to modify the version to create additional features... if so what features?... any windows interface, bluetooth interface, etc?Any other info to share.Look forward to hearing from you.Sherief

author: bmj123
author_rank: Newbie
timestamp: February 16, 2022, 08:39:42 am
content: Hi ,Can you share your email address? I can send you all details you have asked .I need your some additional feature to be added in this which we will discuss in detail.RegardsBal Mukund

author: Uunoctium
author_rank: Frequent Contributor
timestamp: February 16, 2022, 10:22:35 am
content: tl;drI would recommend to use an 1wire current transfomer connected to an scope and the device terminated with real patient-impedance. So you can observe all pulses with their individual rise & fall ramps under real conditions...

author: Terry Bites
author_rank: Super Contributor
timestamp: February 16, 2022, 01:08:20 pm
content: Do you want to measure the current waveform on a scope or a peak/average on a DVM?The waveforms are complex.

author: Terry Bites
author_rank: Super Contributor
timestamp: February 16, 2022, 02:49:15 pm
content: 1uA -400uA measured with a CTR?

author: Uunoctium
author_rank: Frequent Contributor
timestamp: February 17, 2022, 09:57:10 am
content: of course ;-)since 50 yrs we are lifting lousy levels from MC-cartridges to useful ones through step-up transformers. Output is in the region of 150µV or less.Years ago I salvaged differential current transformers from damaged personal-RCD's.With only the interconnection cable of an outdated TENS/EMC device fed through the core, I got this...(second image shows device set to 50% max level. Terminated with 20 MegOhm. Pls note the scale factor :-))

author: Uunoctium
author_rank: Frequent Contributor
timestamp: February 17, 2022, 10:40:30 am
content: since hv-Tens was not the question - is that solution suitable for measuring µA?With 10 turns on primary and series resistor (as a normed patient-impedance) of 2kOhms: maybe. Down at 20µA I got an voltage reading on 2465 of approx 2mVss. Rigol (snapshot) is too noisy at these levels...second = 100µAthird = 400µA(AC current was adjusted via 50Hz low voltage variac & voltage drop measured across the 2kOhm via Keithley2000)

author: Terry Bites
author_rank: Super Contributor
timestamp: February 17, 2022, 01:10:16 pm
content: The machine must have its own internal current setting. The software package (Inspirstar Profile Editor – Professional) seems to set many parameters including set current. Its not clear if it is monitoring the actual current delivered: call MENDThe user manual: mendtechnology.com › uploads › 2016/03 describes the curent waveforms on page 20. If you meaure pulse by pulse then averaging is easy.If you modify the existing machine you will invalidate any medcal device approvals is has. It is a class II medical device.So I'm thinking that ASIC such as the INA190xx in an isolated system would be great for accurate current measurements.

author: bmj123
author_rank: Newbie
timestamp: February 19, 2022, 11:14:43 am
content: plz find circuit design

author: bmj123
author_rank: Newbie
timestamp: February 20, 2022, 12:39:00 am
content: Please suggest how to make this better

author: bmj123
author_rank: Newbie
timestamp: February 20, 2022, 12:39:53 am
content: Please suggest how to make this better

author: Uunoctium
author_rank: Frequent Contributor
timestamp: February 20, 2022, 02:23:48 pm
content: According to manual, PR0 PR1 can be configured as Xtal1 Xtal2 (pin 91, pin 92)So the mcu is determined:https://www.mouser.de/datasheet/2/268/Atmel-8067-8-and-16-bit-AVR-Microcontrollers-ATxme-1315801.pdfNH245 = SN74LVC8T245https://pdf1.alldatasheet.com/datasheet-pdf/view/177125/TI/NH245.htmlLooking at the waveforms my first though was: we building an mini-mooghttp://www.sdiy.org/philgallo/mgbvca.htmlThere are lots of diy-projects about synth. And some are using exact this mcu for that purpose...

author: Uunoctium
author_rank: Frequent Contributor
timestamp: February 20, 2022, 02:38:48 pm
content: btw - that makes it much easier retracing an pcb

author: bmj123
author_rank: Newbie
timestamp: February 24, 2022, 02:59:50 pm
content: thanks for all help any agencies who can really complete these project