# Arduino Arpegiator module **URL:** \ **Category:** DIY STUFF\ **Created:** [December 30, 2020, 4:08pm UTC](https://lookmumnocomputer.discourse.group/t/arduino-arpegiator-module/2581 "2020-12-30T16:08:46Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Dud](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/dud/32/610_2.png) [@Dud](https://lookmumnocomputer.discourse.group/u/Dud)\ **Post date:** [December 30, 2020, 4:08pm UTC](https://lookmumnocomputer.discourse.group/t/arduino-arpegiator-module/2581/1 "2020-12-30T16:08:47Z")
[![](https://global.discourse-cdn.com/free1/uploads/lookmumnocomputer/original/2X/e/ed0b4c2985232aec51ec1d2227023138b15d4c70.jpeg "DIY ARDUINO ARPEGGIATOR - [YMNK's DIY synths adventures]") ](https://www.youtube.com/watch?v=p_Mg5N31y4s) schematic and code [http://www.ymnkmusic.com/projects/arpeggiator.php](http://www.ymnkmusic.com/projects/arpeggiator.php) ---
**Author:** ![analogoutput](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/analogoutput/32/29663_2.png) [@analogoutput](https://lookmumnocomputer.discourse.group/u/analogoutput)\ **Post date:** [December 30, 2020, 4:21pm UTC](https://lookmumnocomputer.discourse.group/t/arduino-arpegiator-module/2581/2 "2020-12-30T16:21:48Z")
Nice, I’d want a little more protection on that clock input though. ---
**Author:** ![Dud](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/dud/32/610_2.png) [@Dud](https://lookmumnocomputer.discourse.group/u/Dud)\ **Post date:** [December 30, 2020, 4:51pm UTC](https://lookmumnocomputer.discourse.group/t/arduino-arpegiator-module/2581/3 "2020-12-30T16:51:02Z")
A question, are the 2 GND pin on an arduino need a connection to GND ? I think about another schem, because he don’t write GND connection on it : ![generative arduino sequencer](https://global.discourse-cdn.com/free1/uploads/lookmumnocomputer/original/2X/5/5956b54b39220ffca37fdf15eb04651c0385e7fc.jpeg) on other arduino project schem i find only the GND pin near Vin connect to GND, the 2 GND pin are connect inside together ? ---
**Author:** ![eric](https://avatars.discourse-cdn.com/v4/letter/e/898d66/32.png) [@eric](https://lookmumnocomputer.discourse.group/u/eric)\ **Post date:** [December 30, 2020, 7:05pm UTC](https://lookmumnocomputer.discourse.group/t/arduino-arpegiator-module/2581/4 "2020-12-30T19:05:26Z")
On the nano, I usually connect just one, the most easy one to connect in that project, and it always worked… Looking at the schematics, they are connected internally. > **[Arduino\_Nano-Rev3.2-SCH.pdf](https://www.arduino.cc/en/uploads/Main/Arduino_Nano-Rev3.2-SCH.pdf)** > > 79.15 KB ---
**Author:** ![eric](https://avatars.discourse-cdn.com/v4/letter/e/898d66/32.png) [@eric](https://lookmumnocomputer.discourse.group/u/eric)\ **Post date:** [December 30, 2020, 9:03pm UTC](https://lookmumnocomputer.discourse.group/t/arduino-arpegiator-module/2581/5 "2020-12-30T21:03:51Z")
But remember, that’s for a Nano. If you are using a bare '328, which has also two GND pins, you _need_ to connect _both_ to gnd… ---
**Author:** ![twinturbo](https://avatars.discourse-cdn.com/v4/letter/t/8baadc/32.png) [@twinturbo](https://lookmumnocomputer.discourse.group/u/twinturbo)\ **Post date:** [December 30, 2020, 9:27pm UTC](https://lookmumnocomputer.discourse.group/t/arduino-arpegiator-module/2581/6 "2020-12-30T21:27:21Z")
Think I can get that Nocked up and sent to JLC tomorrow, Try and tag it into the other boards I have in the Pipe Line 😉 Rob ---
**Author:** ![Dud](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/dud/32/610_2.png) [@Dud](https://lookmumnocomputer.discourse.group/u/Dud)\ **Post date:** [December 30, 2020, 9:34pm UTC](https://lookmumnocomputer.discourse.group/t/arduino-arpegiator-module/2581/7 "2020-12-30T21:34:15Z")
what’s bare’328 ? only the chip ? ---
**Author:** ![Farabide](https://avatars.discourse-cdn.com/v4/letter/f/ecc23a/32.png) [@Farabide](https://lookmumnocomputer.discourse.group/u/Farabide)\ **Post date:** [December 30, 2020, 9:56pm UTC](https://lookmumnocomputer.discourse.group/t/arduino-arpegiator-module/2581/8 "2020-12-30T21:56:24Z")
Yes. Chip only. Without the board the grounds are not linked. That said it’s a very forgiving chip for power. ---
**Author:** ![BlackDeath](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/blackdeath/32/7644_2.png) [@BlackDeath](https://lookmumnocomputer.discourse.group/u/BlackDeath)\ **Post date:** [December 30, 2020, 10:09pm UTC](https://lookmumnocomputer.discourse.group/t/arduino-arpegiator-module/2581/9 "2020-12-30T22:09:24Z")
Check out his insta, this guy is building Kosmo! Is he a poster here? ---
**Author:** ![Farabide](https://avatars.discourse-cdn.com/v4/letter/f/ecc23a/32.png) [@Farabide](https://lookmumnocomputer.discourse.group/u/Farabide)\ **Post date:** [December 30, 2020, 10:20pm UTC](https://lookmumnocomputer.discourse.group/t/arduino-arpegiator-module/2581/10 "2020-12-30T22:20:42Z")
@Dud has a similar panel style. @dud is this yours too? ---
**Author:** ![Dud](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/dud/32/610_2.png) [@Dud](https://lookmumnocomputer.discourse.group/u/Dud)\ **Post date:** [December 30, 2020, 10:48pm UTC](https://lookmumnocomputer.discourse.group/t/arduino-arpegiator-module/2581/11 "2020-12-30T22:48:29Z")
thx @eric & @Farabide ! … it’s not me : too many white panel 😁 ---
**Author:** ![twinturbo](https://avatars.discourse-cdn.com/v4/letter/t/8baadc/32.png) [@twinturbo](https://lookmumnocomputer.discourse.group/u/twinturbo)\ **Post date:** [December 31, 2020, 11:38am UTC](https://lookmumnocomputer.discourse.group/t/arduino-arpegiator-module/2581/12 "2020-12-31T11:38:09Z")
I am working on this and have simplified it ( I think ) Using GND rail for the switches and INPUT\_PULLUP in the code should allow for all of the resistors to be removed. I hope… ---
**Author:** ![twinturbo](https://avatars.discourse-cdn.com/v4/letter/t/8baadc/32.png) [@twinturbo](https://lookmumnocomputer.discourse.group/u/twinturbo)\ **Post date:** [December 31, 2020, 12:18pm UTC](https://lookmumnocomputer.discourse.group/t/arduino-arpegiator-module/2581/13 "2020-12-31T12:18:13Z")
I have left the resistor on the clock, but I will try it without and set Input\_Pullup on that. ![SCHEMPIC](https://global.discourse-cdn.com/free1/uploads/lookmumnocomputer/original/2X/d/d2ac13da2cd9d51c2c5c6d0d9f72f9149fdc8fb9.png) ---
**Author:** ![Jos](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/jos/32/151_2.png) [@Jos](https://lookmumnocomputer.discourse.group/u/Jos)\ **Post date:** [December 31, 2020, 12:32pm UTC](https://lookmumnocomputer.discourse.group/t/arduino-arpegiator-module/2581/14 "2020-12-31T12:32:26Z")
> [@twinturbo](#): > > INPUT\_PULLUP in the code should allow for all of the resistors to be removed First thing I thought when I had a look at the schematic ! Just wire the switches on D2 … D13 to GND, and invert the value you read. Furthermore you do not need to use a 78x05. The arduino nano can be powered using the VIN input which can be used for an unregulated 7 to 12 Volts DC. ---
**Author:** ![analogoutput](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/analogoutput/32/29663_2.png) [@analogoutput](https://lookmumnocomputer.discourse.group/u/analogoutput)\ **Post date:** [December 31, 2020, 1:21pm UTC](https://lookmumnocomputer.discourse.group/t/arduino-arpegiator-module/2581/15 "2020-12-31T13:21:13Z")
And they connected the 78x05 to VIN, which is incorrect. ---
**Author:** ![twinturbo](https://avatars.discourse-cdn.com/v4/letter/t/8baadc/32.png) [@twinturbo](https://lookmumnocomputer.discourse.group/u/twinturbo)\ **Post date:** [December 31, 2020, 1:43pm UTC](https://lookmumnocomputer.discourse.group/t/arduino-arpegiator-module/2581/16 "2020-12-31T13:43:44Z")
Yeah I used +5 in. Couple of alterations on the schematic for mechanical interface layer… PCB all but done ![PCBPIC](https://global.discourse-cdn.com/free1/uploads/lookmumnocomputer/original/2X/0/0062341da6a41e704c3c24bf330cb3f2a6396401.png) ---
**Author:** ![analogoutput](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/analogoutput/32/29663_2.png) [@analogoutput](https://lookmumnocomputer.discourse.group/u/analogoutput)\ **Post date:** [December 31, 2020, 1:46pm UTC](https://lookmumnocomputer.discourse.group/t/arduino-arpegiator-module/2581/17 "2020-12-31T13:46:52Z")
I’d use a series resistor and a couple Schottkys to the rails (instead of the series diode and resistor to ground) on the clock input: ![image](https://global.discourse-cdn.com/free1/uploads/lookmumnocomputer/original/2X/1/1bacff9da5e9730456d5c1688f079c5b40a405ad.png) Yes, the ATMEGA328P has internal protection diodes, but the datasheet nevertheless says maximum input voltage is -0.5 V, Vcc+0.5 V. Likewise the output pin on the MCP4725 is supposed to be within -0.3 V, Vdd+0.3 V, and output current is max 25 mA, so it should have similar protection. Or buffer with an op amp. ---
**Author:** ![twinturbo](https://avatars.discourse-cdn.com/v4/letter/t/8baadc/32.png) [@twinturbo](https://lookmumnocomputer.discourse.group/u/twinturbo)\ **Post date:** [December 31, 2020, 2:14pm UTC](https://lookmumnocomputer.discourse.group/t/arduino-arpegiator-module/2581/18 "2020-12-31T14:14:37Z")
I will take your advice and update the Input. ---
**Author:** ![twinturbo](https://avatars.discourse-cdn.com/v4/letter/t/8baadc/32.png) [@twinturbo](https://lookmumnocomputer.discourse.group/u/twinturbo)\ **Post date:** [December 31, 2020, 2:43pm UTC](https://lookmumnocomputer.discourse.group/t/arduino-arpegiator-module/2581/19 "2020-12-31T14:43:02Z")
Revised, just got to update the PCB ![SCHEMPIC2](https://global.discourse-cdn.com/free1/uploads/lookmumnocomputer/original/2X/d/d97ab1acfc54bc7221091b4a7b8904b0b02f8108.png) ---
**Author:** ![Farabide](https://avatars.discourse-cdn.com/v4/letter/f/ecc23a/32.png) [@Farabide](https://lookmumnocomputer.discourse.group/u/Farabide)\ **Post date:** [December 31, 2020, 4:14pm UTC](https://lookmumnocomputer.discourse.group/t/arduino-arpegiator-module/2581/20 "2020-12-31T16:14:15Z")
I like that approach. It’s elegant and yet belt and braces too. Pinched for my notes. Thank you. [Next page](https://lookmumnocomputer.discourse.group/t/arduino-arpegiator-module/2581.md?page=2)