Talk:DreamTeam/Brainduino - Revision history

198.27.140.180: /* March 21 2017 */

2017-03-22T03:09:33Z

March 21 2017

← Older revision		Revision as of 20:09, 21 March 2017
Line 1:		Line 1:
	==March 21 2017==		==March 21 2017==
	Q&A with Masahiro!		Q&A with Masahiro!

	<<		<<
	We are making progress on our Brainduino V0.1 assembly. We think we isolated the abnormality to IC3, the low-pass filters. We observe 10,000x gain out of the first two rounds of amplification. Our understanding is that 10,000x gain amplifies a +/-50uV brain powered signal to a +/-0.5V signal, within the operational range of the Arduino ACD.		We are making progress on our Brainduino V0.1 assembly. We think we isolated the abnormality to IC3, the low-pass filters. We observe 10,000x gain out of the first two rounds of amplification. Our understanding is that 10,000x gain amplifies a +/-50uV brain powered signal to a +/-0.5V signal, within the operational range of the Arduino ACD.
Line 47:		Line 48:

	C46 1µF is option. default is put 0 ohm.		C46 1µF is option. default is put 0 ohm.


	==March 08 2017==		==March 08 2017==

198.27.140.180: March 21 2017

2017-03-22T03:06:12Z

March 21 2017

← Older revision		Revision as of 20:06, 21 March 2017
Line 1:		Line 1:
	==March 08 ~~2016~~==		==March 21 2017==
			Q&A with Masahiro!
			<<
			We are making progress on our Brainduino V0.1 assembly. We think we isolated the abnormality to IC3, the low-pass filters. We observe 10,000x gain out of the first two rounds of amplification. Our understanding is that 10,000x gain amplifies a +/-50uV brain powered signal to a +/-0.5V signal, within the operational range of the Arduino ACD.
			>>

			Maybe not easy understanding of so many option setup.


			We use option A.
			OPA2111 set gain X 100.
			AD8422 use as Gain X1 ( no need put R5 & R6 to AD8422 , because we use option A )

			How to get X100 :
			R23 (100K) / R27 (2K) = 50
			R24 (100K) / R27 (2K) = 50
			50 + 50 = 100


			Then IC3D set gain X250

			How to get X250 :
			1 + (R16 (1M) / R15 (4.02K) ) = 250 (249.75622)



			Total : X 100 X 250 = X 25,000

			It is not X 10,000.


			C15 : 1 µF makes 0.16Hz low cut ( default )
			C15 : 0.1 µF makes 1.6Hz low cut.

			C35 : 47 pF makes 3200 Hz high cut ( default )
			C35 : 1 nF makes 160 Hz high cut

			Need setup for other channel too.

			[[File:Brain-duino_circuit.png]]

			<<Coming out of the first and second round of filters in IC3 on both channels we're seeing our signal clipping at +/-12V. Is this expected? >>

			From IC3 output, max clip is +-12V.
			Usually not clip to +-12V. In case clip continue then not working.
			Make sure solder jumper : SJ8 : 2-3 connect is default.

			C46 1µF is option. default is put 0 ohm.


			==March 08 2017==

	Debugging the brainduino v0.1_foo ...		Debugging the brainduino v0.1_foo ...

192.195.83.130: brainduino debugaloo

2017-03-09T06:56:46Z

brainduino debugaloo

← Older revision		Revision as of 23:56, 8 March 2017
Line 1:		Line 1:
			==March 08 2016==

			Debugging the brainduino v0.1_foo ...

			One of these resistors is not like the other.

			R15 is upside down ?
			A 4.02 KOhm resistor.
			(John wonders if this is a correct value for setting op-amp gain anyway,
			given the corresponding 1 MOhm resistor in that part of the circuit.)

			R17 the same ... maybe not upside down afterall. Jade observes that neither R15 or R17 have any visible printing on the side facing up, unlike any of the many many other resistors on the board.
			Hence the initial speculation as to its potential upside-downness ...

			Breaking out the multimeter now ... Here we go ... What's going on with this multimeter ?

			Now reads 4.01 KOhm on R15
			same on R17, very good.

			The feedback resistors R16 and R19:
			R16: 1.001 MOhm
			R19: 1.001 MOhm

			C35 difficult to get consistent reading of capacitance (maybe due to rest of circuit not isolated)
			C36 11.85 nanoFarads ? Also not consistent .007 nanoFarads ... 0.4 ... 2. ... 1. ... 0.006
			ok, we want 0.047 nanoFarads ie 47 picoFarads as specified in schematic
			but we never see that ...
			but that's okay, because measuring capacitance in circuit is a fool's errand.

			backing up a bit ...
			R3 tests within 2% of 1 MegaOhm despite being GROSSLY OFF CENTER
			R4 1.000 MegaOhm feels more solid than R3

			should we resolder R3 ?

			John would (if not feeling adventurous) read documentation
			and study IC 1b and IC 1a ...

			Dan, feeling adventurous, reads Masahiro's instructables article
			which is full of win, and yields A CLUE as per corner frequency of the
			EIGHT POLE BUTTERWORTH FILTER: "1/100 of clock is filter high cut frequency."









	==December 21 2016==		==December 21 2016==
	Understanding the brainduino v0.1		Understanding the brainduino v0.1

192.195.83.130: /* December 21 2016 */ sp

2017-01-05T02:59:01Z

December 21 2016: sp

← Older revision		Revision as of 19:59, 4 January 2017
Line 13:		Line 13:
	Voltage divider (cf LT1761) built around SJ10, SJ11		Voltage divider (cf LT1761) built around SJ10, SJ11
	a voltage divider for each channel ...		a voltage divider for each channel ...
	also linked with ~~caoacitors~~ (two 10 microFarad on input, 0.1 microFarad for each output channel)		also linked with capacitors (two 10 microFarad on input, 0.1 microFarad for each output channel)

	Op Amps		Op Amps

192.195.83.130: /* December 21 2016 */

2016-12-22T06:14:46Z

December 21 2016

← Older revision		Revision as of 23:14, 21 December 2016
Line 6:		Line 6:
	LT1761 - 100mA, Low Noise, LDO Micropower Regulators		LT1761 - 100mA, Low Noise, LDO Micropower Regulators
	(IC7) (5 Volts for DC offset, 2.5 V after voltage divider,		(IC7) (5 Volts for DC offset, 2.5 V after voltage divider,
	feeds + signal inputs of 2 different op amps)		feeds + signal inputs of 2 different op amps, also provides 5 V reference for Arduino)

	RB-0512 - +/- 12 V for op amp (RB-0512 D/P -- recom 12v dc/dc converter)		RB-0512 - +/- 12 V for op amp (RB-0512 D/P -- recom 12v dc/dc converter)

192.195.83.130: image links

2016-12-22T04:15:19Z

image links

← Older revision		Revision as of 21:15, 21 December 2016
Line 28:		Line 28:

	verified IC5, IC6 not populated ...		verified IC5, IC6 not populated ...

	~~[[File:IMG_9574.jpg]]~~
	~~[[File:IMG_9573.jpg]]~~

	still looking for IC7!		still looking for IC7!
Line 50:		Line 47:
	both contact R29 which is 2.15 K Ohms to ground		both contact R29 which is 2.15 K Ohms to ground

	[[~~File~~:IMG_9574.jpg]]		[[Image:IMG_9574.jpg\|600px]]
	[[~~File~~:IMG_9573.jpg]]		[[Image:IMG_9573.jpg\|600px]]

	==December 14 2016==		==December 14 2016==

192.195.83.130: interim save

2016-12-22T04:10:54Z

interim save

← Older revision		Revision as of 21:10, 21 December 2016
Line 5:		Line 5:

	LT1761 - 100mA, Low Noise, LDO Micropower Regulators		LT1761 - 100mA, Low Noise, LDO Micropower Regulators
	(5 Volts for DC offset, 2.5 V after voltage divider,		(IC7) (5 Volts for DC offset, 2.5 V after voltage divider,
	feeds + signal inputs of 2 different op amps)		feeds + signal inputs of 2 different op amps)

	RB-0512 - +/- 12 V for op amp (RB-0512 D/P -- recom 12v dc/dc converter)		RB-0512 - +/- 12 V for op amp (RB-0512 D/P -- recom 12v dc/dc converter)
	(drives all op amps)		(drives all op amps, also feeds LT1761)

	Voltage divider (cf LT1761) built around SJ10, SJ11		Voltage divider (cf LT1761) built around SJ10, SJ11
Line 16:		Line 16:

	Op Amps		Op Amps
	* for amplification		* for amplification (instrumentation amp setup)
	* for filtering		* for filtering (capacitors C15 and C11

	Butterworth filter		Butterworth filter
Line 23:		Line 23:
	Arduino (ADC, communication with Bluetooth module)		Arduino (ADC, communication with Bluetooth module)

			... examining the hardware:
			question about IC2 - funky solder, corrosion?
			First amplifier of channel one (IC2A and IC2B)

			verified IC5, IC6 not populated ...

			[[File:IMG_9574.jpg]]
			[[File:IMG_9573.jpg]]

			still looking for IC7!
			found it. It has some funky solder right next to it.
			IC7 is tiny. Is it actually IC7?
			Unlabeled solder blob next to it has white rectangle printed around it ... so maybe solder jumper

			IC7 connects to C32

			SJ16 is one step closer to bringing voltage divider into effect.

			Can measure on blob for 5 Volts ...

			There may be some test points near U$7

			Some resistors from divider network identified?
			R39 is 4.3 K Ohms
			R34 and R35 are each 10 K Ohms ?
			both contact R29 which is 2.15 K Ohms to ground

			[[File:IMG_9574.jpg]]
			[[File:IMG_9573.jpg]]

	==December 14 2016==		==December 14 2016==

192.195.83.130: brainduino analysis

2016-12-22T03:23:22Z

brainduino analysis

← Older revision		Revision as of 20:23, 21 December 2016
Line 1:		Line 1:
			==December 21 2016==
			Understanding the brainduino v0.1

			Power supplies, voltage/current regulator. voltage reference

			LT1761 - 100mA, Low Noise, LDO Micropower Regulators
			(5 Volts for DC offset, 2.5 V after voltage divider,
			feeds + signal inputs of 2 different op amps)

			RB-0512 - +/- 12 V for op amp (RB-0512 D/P -- recom 12v dc/dc converter)
			(drives all op amps)

			Voltage divider (cf LT1761) built around SJ10, SJ11
			a voltage divider for each channel ...
			also linked with caoacitors (two 10 microFarad on input, 0.1 microFarad for each output channel)

			Op Amps
			* for amplification
			* for filtering

			Butterworth filter

			Arduino (ADC, communication with Bluetooth module)


			==December 14 2016==
	what is value of c33? 50 pF or 1 nF ?		what is value of c33? 50 pF or 1 nF ?
	determines high-cut frequency either 160 Hz (1 nF) or 3200 Hz (50 pF)		determines high-cut frequency either 160 Hz (1 nF) or 3200 Hz (50 pF)

Danf: validation plan

2016-12-15T06:49:35Z

validation plan

← Older revision		Revision as of 23:49, 14 December 2016
Line 31:		Line 31:
	(or if no offset voltage and input is actually ~ -5 to +5 millivolts,		(or if no offset voltage and input is actually ~ -5 to +5 millivolts,
	then output will be -0.5 to +0.5 volts)		then output will be -0.5 to +0.5 volts)

			(however, there is a +2.5 Volt DC offset impinging on the AD2177 part of the instrumentation amp setup
			... we think this is ok to say ... But is option A grounded -- no offset -- or 2.5 volts ?

	where might DC offset voltage come into play?		where might DC offset voltage come into play?
Line 43:		Line 46:

	4th Stage IC3D>IC3C Ch1, and IC3A>IC3B, Potentially considered a two-pole high-cut(aka low-pass)		4th Stage IC3D>IC3C Ch1, and IC3A>IC3B, Potentially considered a two-pole high-cut(aka low-pass)


			Next week: verify 101 x gain, 100 x gain, DC offset !

Danf: calculating expected gains

2016-12-15T06:36:04Z

calculating expected gains

@@ Line 3: / Line 3: @@
 Op amps ...
 OPA2111 - what gain? expecting ~ 100 ?
@@ Line 14: / Line 15: @@
 + (R23 + R24) / R27 ...
 so 1 + (200 K / 2 K) = 101
 nd Stage AD8422 Instrumentation amp with gain resistor