Electronics Lab Philippines

Electronic Bongos

Offline zirlou21

  • *******
  • 762
  • 84
  • Gender: Male
  • I wish there is GOD...
    • ARDUINO,ATMEL-AVR,ZILOG ENCORE,PIC..CIRCUITS/APPS
Re: Electronic Bongos
« Reply #40 on: August 18, 2020, 06:48:29 PM »
...
tamang tama yan para DIY SPWM converter, dami naglabasan DIY sine pwm converter based on china's ASIC EG8010 homegrown chip may ready module sila na EGS002 SPWM complete w/ IR2110 mosfet drive in full bridge config. available sa Lazada EGS002
at dami support docu online, pakisilip baka makagawa naman w/ our version. ala na ako scope at freq counter.
...NO OFFENSE pls..usapang teknikal lang,walang personalan.....

Offline bravokilo

  • *****
  • 6707
  • 185
  • Gender: Male
Re: Electronic Bongos
« Reply #41 on: August 18, 2020, 07:20:16 PM »
HI SUPER AND ZIRLOU. NUNG NAKITA KO ANG TOPIC, AKALA KO ELECTRONIC BongKo. Naku, mareplace na aku. I have 3 copong copong na scope, puro de tubo. isa lang gumagana pa. Pagong ang freq.pero who cares, I only used it for the RC radio.

Offline zirlou21

  • *******
  • 762
  • 84
  • Gender: Male
  • I wish there is GOD...
    • ARDUINO,ATMEL-AVR,ZILOG ENCORE,PIC..CIRCUITS/APPS
Re: Electronic Bongos
« Reply #42 on: August 18, 2020, 08:04:57 PM »
...
hello sirBK, long time no talk..
nakita ko Lazada mga IC rx/tx na nafeature nyo wayback available na. i'm working on 433Mhz at 2.4Ghz transciever para sa wireless controller ng mga digital scoreboards timer dami sa lazada like NRF24L01+ CC1101 at mga rf modules from egizmo, hinahanda ko pa i feature ko sa thread ko about micro.
...NO OFFENSE pls..usapang teknikal lang,walang personalan.....

Offline bravokilo

  • *****
  • 6707
  • 185
  • Gender: Male
Re: Electronic Bongos
« Reply #43 on: August 20, 2020, 05:38:42 AM »
...
hello sirBK, long time no talk..
nakita ko Lazada mga IC rx/tx na nafeature nyo wayback available na. i'm working on 433Mhz at 2.4Ghz transciever para sa wireless controller ng mga digital scoreboards timer dami sa lazada like NRF24L01+ CC1101 at mga rf modules from egizmo, hinahanda ko pa i feature ko sa thread ko about micro.


Sounds good for our nubies to play with those ICs. I expect more proprietary ICs to be be dumped here cuz production has slowed down significantly in China. Many manufacturers are running at lower capacities now. Have you come across Bluetooth  modules?

Offline Super zHero

  • *****
  • 5773
  • 310
  • Simple problem- ...simple solution.
Re: Electronic Bongos
« Reply #44 on: September 17, 2020, 08:53:49 AM »
Continuing on with this Cabonga build....

I drafted a proto PCB for SMDs.  Only the trimmer pots are not SMDs so there are holes for them.



I drew this in Corel 12, printed it on Imari glossy paper, mirrored.  The copper clad board measures 2" x 3" bought from DEECO.  This artwork will be faced down on the copper and hot-ironed for Toner Transfer method.

Offline Super zHero

  • *****
  • 5773
  • 310
  • Simple problem- ...simple solution.
Re: Electronic Bongos
« Reply #45 on: September 17, 2020, 11:17:24 AM »
The PCB material was fine sanded and cleaned with a degreasing agent like denatured alcohol, acetone or lacquer thinner.  Then I taped the artwork on it with high-temp tape and pressed a hot iron (plantsa) for a few minutes with firm pressure making sure all corners are covered.

Here is the result after peeling off the paper under cold tap water:



I re-use my Ferric Chloride, but my trick is that I warm up the solution to maybe 40-50 deg C for faster and cleaner etches.

Offline Super zHero

  • *****
  • 5773
  • 310
  • Simple problem- ...simple solution.
Re: Electronic Bongos
« Reply #46 on: September 17, 2020, 11:28:30 AM »
After etching I wiped off the remaining toner on the copper with lacquer thinner.  It was very important that I made sure the surface was CLEAN for tinning the copper.



Then I dipped the PCB on a small amount of tinning solution called "Liquid Tin" that I think I ordered from Amazon a while back.  There's some over-etching on the lower, right corner of the copper pour that I think resulted from an unclean area of the copper that the toner didn't stick to properly.

Offline Super zHero

  • *****
  • 5773
  • 310
  • Simple problem- ...simple solution.
Re: Electronic Bongos
« Reply #47 on: September 25, 2020, 10:59:21 PM »
OK, so I was thinking of laying a Green Solder Mask on this but since it's only a proto PCB, I decided not to since I want to prove that the board works first.  So I populated only half of the board or one circuit.  The other half is the same/similar circuit.

This design uses an LM324 quad op-amp.  The two op-amps on pins 1-7 compose one circuit, and the other two on pins 8-14 the other circuit.



Even though this is an SMD board, it has 41 holes for the trim pots, a couple of jumpers, an outboard volume pot and three headers.  I think I have 11 SMD 0805 components on this other than the IC on the first circuit.

I found out later that my LM324 was fried so I used a TL074 instead.  Same pin-out.

Offline Super zHero

  • *****
  • 5773
  • 310
  • Simple problem- ...simple solution.
Re: Electronic Bongos
« Reply #48 on: September 25, 2020, 11:05:54 PM »
The topside of the board has the trim pots and the headers.



The board works :)

Offline Super zHero

  • *****
  • 5773
  • 310
  • Simple problem- ...simple solution.
Re: Electronic Bongos
« Reply #49 on: Today at 02:25:16 PM »

In the original Cabonga is this wave-shaping circuit:



It takes a short duration switch closure and turns it into a shorter, timed "pulse" to trigger the oscillator/filter circuit.

S1 is the momentary switch that serves as the sensor when the drum head is hit.  It applies +9V to R1, a limiting resistor, to R2 & C1 which gives a timed pulse passing to C2 and D2, thru R3, another limiting resistor, to the op-amp circuit.  D1 grounds any negative-going signal.

This set of waveforms show, on top (YEL) the +9V entering R1:



The bottom (VIO) is the pulse to the left of R3.  It shows about 7V peak.  Horizontal scale is 5mS.

Offline Super zHero

  • *****
  • 5773
  • 310
  • Simple problem- ...simple solution.
Re: Electronic Bongos
« Reply #50 on: Today at 02:37:29 PM »
What the op-amp 'sees' is this signal:



Again, the top is the +9V at R1.  The bottom is the 'pulse' to the right of R3 (330K) with 1Meg to GND for a load.  These measurements were made on a solderless breadboard and not on an actual Cabonga original circuit.

If you noticed, no matter the length of the input signal, the output pulse remains the same, if the input is not shorter than the R-C time constant.  Again, the horizontal scale is 5mS / div.

Offline Super zHero

  • *****
  • 5773
  • 310
  • Simple problem- ...simple solution.
Re: Electronic Bongos
« Reply #51 on: Today at 04:28:22 PM »

The major disadvantage of the original Cabonga is its lack of Velocity, meaning- however soft or hard you hit the drum head, the sound generated is the same.  This is due to the way the pulse is generated.  Same voltage, same time constant everytime.

In my version, I'm using a piezo transducer and not a switch for my drum sensor.  The piezo generates its own voltage, and will vary to how hard or soft it senses the hit.  This reduces the component count of the circuit, and no more fine-tuning of a switch as in the old Cabonga.  Reduced cost.

Offline Super zHero

  • *****
  • 5773
  • 310
  • Simple problem- ...simple solution.
Re: Electronic Bongos
« Reply #52 on: Today at 04:37:54 PM »

Here are a couple of 20mm piezo discs.  About the size of a 25 coin.  That black thing is a rubber pad:



Just solder a pair of wires to the inner and outer discs.


Offline Super zHero

  • *****
  • 5773
  • 310
  • Simple problem- ...simple solution.
Re: Electronic Bongos
« Reply #53 on: Today at 04:41:20 PM »

I tidied up the wires with heat-shrink tubing and stuck them to the self-adhesive rubber pads:


Offline Super zHero

  • *****
  • 5773
  • 310
  • Simple problem- ...simple solution.
Re: Electronic Bongos
« Reply #54 on: Today at 04:44:37 PM »

This is the rubber pad I got from Ace, also available at most hardwares or stationery stores: