OpenCircuits:Community portal

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Welcome to Open Circuits. This is a good place to talk about Open Circuits, as a whole.

We have 748 articles now. Yay!


Help, noob looking to get into electronics

I want to create an open hardware smartphone... but I don't know anything about electronics... yet... Someone care to help? I just need to be pointed in the right direction

I'm guessing i just need to create some sort of small computer running linux??

Thanks =)

--RenatoFontes 00:54, 11 February 2011 (UTC)

Yes. the components for a smartphone board are really small so no one has figured out how to build one. My suggestion? Make one with a beagleboard or raspberry pi as a mainboard instead. Both boards are small and low voltage and linux which would be a great smartphone base. that is your best bet, btw it requires moderate electronics know how to rig up a touchscreen. You should get started familiarizing yourself with whatever electronics knowledge that you can find too.

            -Quinn (

Yes. The components for a smartphone board are really small, but lots of people have figured out how to build one -- see Open Mobile Gadgets for a list.

In particular, the Tux phone [1] [2] and the more polished-looking Openmoko FreeRunner [3] [4] have open hardware and open software.

It's possible to build a small computer running Linux "from scratch" -- see motherboards that run Linux for some people who have done just that. Perhaps you can use one of those smartphone hardware or other motherboard hardware as-is? Or perhaps with a few blue-wires? Or perhaps you could at least download the schematics and tweak the design for your new PCBs, rather than starting entirely from scratch? --DavidCary 16:00, 16 July 2012 (UTC)

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electrical mailing lists

Yahoo claims they have 1,831 electrical engineering mailing lists. What would be a good way of letting the people on those lists know about the Open Circuits wiki, without spamming them? --DavidCary 13:30, 31 May 2006 (PDT)

  • Publish cold fusion howto :-)
  • Send one email/week and only once per list. And be on topic, listen carefully for responses.

Freqmax 16:24, 30 July 2007 (PDT)

about Open Circuits

So, is there any connection between , , and this wiki? --DavidCary 23:47, 13 June 2006 (PDT)

No. There is no connection between any of and the other websites listed. Chazegh 02:55, 18 June 2006 (PDT)

web rings

Document an original microcontroller project and join a PIC webring, or AVR webring. 20 June 2006

audio electronics

Is there some other wiki for people to talk about audio electronics? Or is this Open Circuits the best wiki for talking about things like "Analog Devices AN-221: The Alexander current-feedback audio power amplifier" by Mark Alexander ?

I think I would prefer to offload all the audio electronics controversies to some other wiki (but which one?). Still, it would be nice to have some "tips for high-power electronics" here. I imagine that tips page would list the various quirks of high-power MOSFETs, BJTs, TRIACs, and IGBTs, and (given a particular motor or speaker or other load) how to select one over the others, and various ways of working around those quirks. -- 07:17, 10 August 2006 (PDT)

I just joined Open Circuits. I have been servicing and designing audio equipment for several years (Recording consoles a specialty) I hope you will have a section for audio electronics. I also work with video projection systems and theatrical lighting (stage struck at an early age) I play electric rock-blues guitar, so I also am interested in tube guitar amps (Marshall and Boogie). And there is a big difference in what a guitar player thinks an amp should do, and what a recording engineer wants an amp for. I think these are valid points for discussion. I've also got an interest in power supplies (my experience is mostly with linear, but I've started learning about switching designs). In fact that brings me to my question, I have some regulator designs based on the 723 that I'd like to share. How do I go about doing that? I built a replacement for a console /- 18V @6A supply when I couldn't find the original regulator devices. I used 723s with external series pass devices. The unit has been working for close to 10 years now, so I think the design is worth sharing. Is anyone interested?

I also research discrete op amps like the Jensen 990. I've been working (on and off for years) on a clone of that using more modern, easily available parts and devices. Anyone else? Finally, in response to the first entry in this section, I too read that application note in Analog Devices Audio/Video Reference Manual. My copy is dated 1992. I've repaired a lot of amplifiers, but haven't built any. If anyone else is hip to this amp I'd like to hear about it. It is a very unique design. I also like the A75 amp design from Nelson Pass and Norman Thagard, and the Leach Amp by Marshall Leach. The last two are pretty normal as far as design goes, not as adventurous as the Alexander with its current-feedback approach. Aloha, RAF-- 14:04, 18 May 2007 (PDT)

取得するには理想靴 ハードであり、ほっそりなるする、より良い形ている が必要、時とさ​​せていただき通常はふくらはぎは​​、降伏それら長い非常に長く、タイト靴を終了 スティッフ天然皮革。ブーツこのふくらはぎは通常です がブーツ選択は、靴で両方 2 結婚指輪、または封印されたが各 とほっそりハーフブーツそうでない場合凹フィート、それがが最も適しのあきらめ半円筒スムーズブーツ、彼ら の太もも見 短く密集と限ら、それはされていることを助ける最高の に持っているに 靴もし特定 粗い、足はできるようにするには摩耗Duantongを助けるために、鐘靴、先行シャットするため湾曲したラウンドブーツ外反母趾膝レッグ、通常の推奨 あなたのための丸みを帯びたへ靴、そして覆わ任意 膝をブーツ大はスカート また、今のいくつかの並べ替えの周りにいる相手オールラウンド、はるか年ほぼすべて メーカー ファッションショー以来理由でその足 シングル製品またはサービス、およびたくさんの多数をそうスタイル、このその冬この種の靴見クレイジーとリンク盛り合わせ機会コネクト、窓、通り、ブーツは高を置くプロファイル、専制それ思える 目を引くブーツはおそらく解消される個人 に歩いて、あるいくつかの 靴、めまい---- 見つけるためにのペアを取得するバレンタインの検索では我々のアドバイスにあるべきです。 自分自身を知ることは通常である 内部の仕組み 今シーズンの最も ブーツスタイル ときのと車輪 靴やブーツの靴スニーカーデザイン要素スポーツ 靴ディシプリン、新鮮完全に新しい人生かどうかそれはねのモデルの形、あるいは素材、色のような開口部 一般的な中で、 はじめに、 から一緒にと LVを有するあなた 超微細に加えて、フェンディゲイリーガジェット男完全犬皮膚 D&靴、グッチパッティング倍高ブーツ、ミュウミュウ靴、シャネル平底ブーツスタイル小剣ブーツこの来る年 、最小限に軽減持っている自然な奪うヌーボー種類 私たちの中 のようなビュー、幾分で接続靴またはwellies、様々な大その段落に向かって養子縁組の側面 新しい要素上 この種の6 詳細任意 しわくちゃの襞のいくつかの並べ替え全体を介してすべての道スムーズと端正な美しされている 深くと恋にうんざり、デザイナーはと恋に落ちた興奮不規則なひだ 生得スムーズの量はていないでしょうではない エッジの効いた味 けちるを一旦組み合わさ倍と同様に少し頑固な、やや野生言語道断が、加えてブーツ同様に、追加されたビットに加え増加したあなた 関わる 3次元印象このドン ボディ全体、強力ビジュアル。印象、思い出に残る[ヒント] UGG ブーツ 2012 実際に真実は非常に "を選択して" 人 いつものブーツに、信じられない現代そして信じられないスレンダー女性の体寸法、それはだ 必要がありますので。間違いない試す 2 UGG クラシックミニ ファジーはこの内今年の流行、湯垢のついた毛深いふんわり見非常に本当に非常に非常に これで信じられないほど暖かい毛皮はが通常である大きい splitを求める多く アール通常 保持 毛皮関係帽子、トップスになりがち、スカート、バッグ、毛皮外出連動。ブーツ言うまでもなく確かにあなたのために秋給電プルに 試してみて、実行する UGG 激安 ふんわり毛皮の使用率が真剣に、ずっと どちらかに沿ってないされていません約と、どちらへ 周り円靴、または 小さい と同様に 2 小上から、また、と ラウンドに加え、 "Q" ハングしただと思う視覚的に非常に。信じられないほど暖かい[ヒント] さすることができますブーツでシルキー感じる普通に楽しいですこのブーツ 最初に 由緒 毛皮に現代センス電流が、外観、日常的な環境はだけではありませんこの壮大な機会は本当にペルソナ失礼よくある靴かもしれません3 ラウンドアラウンドブレ目指して に加えて 服装 秋あなたのために新鮮なのペアリングするのに最適な時間の時間とエネルギーに新鮮の時間から、インストール次に ブーツ一度ストリップホーム、時期 脳 パターンのの形 スニーカー最後良い、つま先その他多数、デザイン タイプファッションもっと感覚少し 感じ知覚印象 スタイルの良い感覚幾分 Aビット A少しいくつかのが少しアール鋭いに加え指摘し、小ラウンドは周りに実際には通常の価値ほとんどです注目のヒントフィート長い片思いが行くブーツ、それがになるラウンド頭見つけるために最善の選択する 爪先繊細を彷彿とさせる4ジッパー オーバーオールジッパーに似て ではない必要がありませんスタイルのときめき のようなラテン系ラテンミス代表の ジッパーから 水配管または純銀 ジッパーブーツ 身体装飾の部分の ミリタリージャケットでジャーキンやオーバーオール、野生スタイル準備がいくつかブーツは単に別の長四〇から五ジッパー 設立一緒に、とその後と本物、変態セクシーに見える。頭が混乱せずにヒント] [足 比べスタウトときめき注意は、最適です、あまりにも ファッション、 05 強調もの。欠点は蘭一緒に 5リベットからこれはジーンズのリベットスキニージーンズは排他的なパートナーとなります配偶者、同様に不定に行きましたの方に向かってゲスト任意ブーツのいくつかの並べ替えのブーツ、装飾的なリベットと豊か外観のあなた靴なぜなら、のその光沢 構造、タフ 金属質感に加えて、 。固体美しさのヒントリベット適切 十分に目を引くたくさんの見栄え ふくらはぎ 男性と女性素晴らしいを集め人々と人はに ないスマート事6 だけではない場所皮膚誇示 靴やブーツハート形溝、または実際 の握り、これらの処理それらの 大部門内 靴やブーツ なり非常に の頭 あなたのこのときめき、と変数 ブーツ内、すべての道を残すセクシーヒントは以来 することができる 色相 1特定のの変化色と接続1、純粋色、実用性より堅牢、あまりに買うために取得する複雑。助けるため摩耗 [1] するために 改訂この文衣装実は、一般的な標準人 だけのような着用スカートA が、 アレンジメントいくつ? そのブーツは良い事実:ブーツ、より多くの重量 はるかにになる軽量化するために取得·フラットが靴やブーツ、好ましくは一緒に薄スカート。ハイヒールブーツは最も有益である同行しっかりカバーまたは。セーターどちらの割合はのいくつかの並べ替えの問題で、 ハワイ ugg はるかに寛大な ドレス、ブーツ付き詳細フラット もっと狭いすべてにセーター、ブーツ使用中が高いを使用しながら、拡張スカート、ブーツとすべてに 研修コース、そこnoです不変ではありませんされていません法律のスラックス となる可能性もあります良い補完するためにブーツに加えてを、このようなから着心地靴、細い字パンツをブーツで沿いとズボンスーツ一般的はるかに優れた耐摩耗ブーツからない靴下を着用していますしない傾向がある。スカートと同様に ベスト、中央残したまま からのセクションをで皮膚上の、摩耗ブーツ、あなたことができます アグオーストラリア 同様に タイツ服は、一緒に臨時ファッションと飾られるセンスミックス。慕わ着用実質的に何もない新しいモデル 靴やブーツ ハード服を "憧れの的ブーツスタイル + ドレスを吊り、ブーツ あの人気エスケープこの特定自然災害 セットであるため、それらの "色 べき材料統一 "決まり文句であることのための無視無視、どんなに幸せへの最善の方法とにかく、秋とこれで今年だけでなく、冬 これのへ毛皮事実上 一緒に持つ

inviting bloggers to open circuits

how to connect a JTAG probe to a Nokia phone

I'd like to invite bloggers such as GyrosGeier to edit OpenCircuits. Rather than just spamming him, I think he would be more inclined to help out if we answered one of his questions first -- such as "If you have information on how to connect a JTAG probe to a Nokia phone, please let me know." Maybe I should start a page on JTAG... --DavidCary 09:37, 22 September 2006 (PDT)

The Hacked Gadgets blog also has a bunch of cool electronics. --DavidCary 11:58, 5 January 2007 (PST)

red links

The default skin at OpenCircuits currently has "red links" = page exists, "dark red links" = page does not exist.

I find that confusing. (But not as bad as the wiki that has some links black-on-white, indistinguishable from normal text).

work-around: Register (it's free, and you don't have to give any personal information), then choose the "preferences" link in the far upper-right corner and then pick any other skin.

The other skins have coloring that you may be more used to from other wiki: "blue links" = page exists, "red links" = page does not exist.

--DavidCary 08:58, 18 December 2006 (PST)

The colors are better in the other skins, but the navigation is worse. How about a new skin that is like the default when it comes to navigation, but uses the normal wiki colors? // Cj 06:45, 4 October 2008 (PDT)

      • Guys, the red color on links is AwuFul, it brings ppl headaches.

That's the only reason I cant participate ***

--Takeda 16:38, 29 September 2007 (PDT)

inviting people from other forums to open circuits

Lots of people talk about circuits for LED lighting at . Perhaps we can talk some of them into contributing here -- perhaps using a page or two of Open Circuits as a FAQ for LEDs and drive circuits.

tool lists

Should we have an entire page on "tools", and mention it on the main page? That risks listing *every* tool anyone has ever heard about, like the page at . Yes, I'm responsible for uglier bits on that page; I think the wide variety of oscilloscopes are particularly confusing. How could we cut through the confusion?

I see the "techniques" page already has a list of software tools. Perhaps it would be nifty to have a short list of all the tools necessary for each technique? Then a beginner would have a better idea of what tools he really needs to get (rather than looking at a huge list of every tool, and wondering for each one, "Am I going to regret buying it when I see it gathering dust? Or am I going to regret not buying it when I need it during a midnight debug session?").

--DavidCary 08:37, 24 January 2007 (PST)

Requests For Help

Thanks for your help with the camcorder mic.

sample component

What is the purpose of the Sample Component ? --DavidCary 16:27, 7 May 2007 (PDT)

current surge and battery life


currently my board is using a 3V battery, in every 40msec it will turn on its RF to communicate with the base station. I face a problem here is that my battery life is badly affected. Turning on the RF with cause a current surge.

Will this surge affect my battery life? If I use a supercapacitor does it helps?

-- User: 04:14, 30 April 2007

MIDI electrical interface

In my opinion, the MIDI interface got a lot of things right that too many later interfaces still trip over.

It may look simple, but too often people try to "improve" it by adding or removing things without understanding, ending up with a worse system.

Is there any other wiki that is more appropriate for explaining the low-level details of the MIDI electrical interface, and *why* it was done that way?

I would be most interested in discussing new communication interfaces -- but is this really the right wiki? Or would or the PICA wiki be better for discussing improvements? --DavidCary 13:21, 21 June 2007 (PDT)

IC design

What do you think about ? Should we talk about VLSI design ("VLSI: designing electronic chips") here at Open Circuits? Or is there a more appropriate wiki somewhere else? --DavidCary 15:59, 26 June 2007 (PDT)

electronics infoline

So have you seen "Free electronics projects" "with Photo Preview" ? --DavidCary 00:28, 1 July 2007 (PDT)

And you will be interested in "online circuit diagrams creation" "for free" ?

generating a netlist with a "C++" program

The "Support Electronics for ATLAS Muon CSC" documentation claims that "The design was captured with C++. There are no schematics." and lists the C++ source code.

How did they do that? --DavidCary 01:15, 3 July 2007 (PDT)

rocket electronics

Is there another wiki that talks about rocket electronics? Or is this Open Circuits the best place to talk about ground support electronics (such as Launch Controllers) and onboard electronics (such as one flight computer or another flight computer )? --DavidCary 14:21, 15 July 2007 (PDT)

Hey David,

In case you haven't heard of it for some strange reason, Hack-a-Day has featured a fair number of rocketry projects over the years, and many of their articles on said projects link back to the original project webpages.

--Purduecer 13:52, 10 April 2009 (UTC)


I have created pages about the Minimig project which is running an Amiga 500 in a Xilinx FPGA. It's rather a work in progress, than a static documentation. I hope nobody minds. Freqmax 18:35, 27 July 2007 (PDT)

すべての服装と靴を含め、ブーツ表示全能視点マインドセットそれはことができますが言ったどちらの、ブーツは特定服靴グレーのみれなければならないのみ適切なが、は現在実際にはもっと光、 これで美しい困難 で内部服アミューズメント ドレス 衣装は、 実際にほとんどです。ほぼすべての力のモデリング、一部ヶ月、埋め付き 感覚の衣装 [2]、上のブーツ ハンサム内、ちょうど作成する 一緒に持つ紛争に加えてスーパーブーツ+ミニスカートの気持ちをから特別なテレスコピックからに処理後の膝のブーツの に対応し、近隣にはに向かっての世話をする脚、スリムな足首、どの皮膚に向かって、方法着用----は注意をINSIDE ルール Uggアウトレット 速く スカート、拡張ブーツ、次にフィート ugg オーストラリア オープン 男旅するあなたは従うことを視力のミックス ugg クラシック トール 靴とミニスカートされてしまった最近深セン天候に着用しているようだった。適応最近オールラウンド 証明書、の位置 冬一見ではなく、 ブーツストリートとしてまた、と 壮大とに加えてしかし、今では人気のあるだけではありませんではないされていない好きなストリート されていません楽しむ、超短衣装と脚ブーツ へ 長いのようにあなたのボディ耐える特定 編集。ベスト 色で着色黒と新しいスカート、経済的にも靴やブーツ光灰色で荒涼とした、濃いグレー 赤にから来るから靴色真紅、また黄褐色、暗赤色真紅などが、 ファッションショーからブラックかもしれないテクスチャの範囲、光沢ブーツ 感じサブ、ダッフル珍しくない共通クラシック暗色、絶妙レイアウト、強調自分臨時感じとユニーク エレガントファッション意味アラウンド少し罰金ファッションとデザイン、ジッパー他と共に、ならびにその他の詳細かもしれない 装飾であることであろうの季節ブーツ アグ ブーツ の機会 ugg ブーツ 通販 することができます通常折衷的であり、高い最高品質優れた革材料、革伸ばすファブリック、スエード、デニム、 ナイロンおよび他材料別のの品種 ブーツ、女の子完全に開示について イン時に長い上の下肢フィート、ブーツ

LaTEX math markup

I wrote a quick howto on figuring out resistor values, but it looks bad without latex math markup enabled. Here's what I wrote as it appears on open circuits: Here's how it appears on wikipedia (with math markup enabled):

Anyone know if this is a quick thing to enable for open circuits or if it's involved?

Mzandrew 14:16, 8 September 2007 (PDT)

DONE! -- Chazegh 00:10, 11 March 2008 (PDT)


I deleted a whole bunch of links that had been placed at the top of this page, probably by the same AH that did it to my page. I think the best solution would be to make it so no edits are possible without being logged in. Then there will be a record of who does this kind of thing. Then they can be banned from the site. I don't think that defeats the purpose of an open wiki environment, it simply means you have to register to contribute.

--RAF 10:30, 21 December 2007 (PST)

At least this page is still OK. The Spam AHole hit my user talk page again today. This is very aggravating.

--RAF 06:54, 22 December 2007 (PST)

I agree. Annoying. I'm starting to "semi-protect" most pages so they can only be edited by logged-in users. I'm leaving a couple of pages wide open as a honeypot and/or test pages, so I can make tests and ban spammers without touching good pages. I think the $wgSpamRegex and/or ReCAPTCHA would be a better way to deal with spam. But my attempt to set them up isn't working yet. Sorry. --DavidCary 10:28, 3 January 2008 (PST)

Release 2.0

New Release 2.0: Open Source Hardware by Jimmy Guterman

Does Guterman know about Open Circuits yet? --DavidCary 01:04, 4 January 2008 (PST)


Should we invite the nice people at tech-assist to use the Open Circuits wiki? --DavidCary 20:38, 15 January 2008 (PST)

A post I left at the Schmartboard mailing list.

Last week I posted to the Schmartboard mailing list asking about more interface types for their system. I made reference to sites like this and pleaded the case of individuals wishing to make projects that interface a little better than the methods available now. Neal Greenburg(VP in sales) replied that they had been kicking ideas around like what I was proposing for a while, and that he would like to get some feedback. So, if you're interested, head on over and pipe in. The basic request I made was asking for common internal pc interfaces(PCI, PCI-e, AGP, ISA, etc..) to be included as an attachable module.

The reason for my request was that this would allow organizations such as this one to develop hardware that is now unachievable at a decent prototyping price(quantities in the single digits). Their modules allow robust SMD hardware to be hand soldered and connected to other modules, but interfacing to a pc or other system is limited to rs232. I left a much more in depth post there, and if you're interested, you can find it there.

I'm not affiliated with schmartboard in any other way than as a customer. I'm sorry if this is seen as spam, it's not intended to be. If the general consensus is that this is spam, feel free to delete it.

Thanks for your time, take care. Jonkopp 13:49, 20 January 2008 (PST)

Making it easier to build common interfaces sounds great. There's a brief mention of Schmartboards at Techniques#Circuit construction .28Prototyping - Other than custom PCB.29. Would you like a Schmartboard page for people to unofficially suggest which Schmartboard fits which SMT package, and -- for those things that don't fit well with any current Schmartboard -- to propose new layouts?
I suspect that the special techniques required for high-speed computer buses (reflected-wave switching, transmission lines, etc.) are not really achievable with prototyping boards, and so require full-custom PCBs.
I think the USB interface, the 30-pin SIMM form factor (for designing uCsimm-like boards), etc. could use a Schmartboard.
--DavidCary 05:55, 5 February 2012 (UTC)

open source machine

Is there some other wiki somewhere that would be better for discussing "open source hardware designs" for non-electronic mechanical hardware, such as ? --DavidCary 05:52, 26 June 2008 (PDT) :-) 2008-11-28


What is up with User talk:Sunnyhouselife, User talk:Kaylee, User talk:Seekic ? I'm guessing that English is not their native language. --DavidCary 08:08, 10 July 2008 (PDT)


Is there a better wiki to discuss ultrasonic stuff? Such as: "FERS: the Flexible, Extensible Radar and Sonar Simulator."


"COSHER stands for Completely Open Source, Headers, Engineering, and Research." --

Can we apply COSHER to open hardware, or does it only apply to software? --DavidCary 04:31, 2 February 2010 (UTC)

Quad Helicopter

Hello, I am starting a project to build a multi-rotor helicopter (starting with a 4 motor one and moving up). I am planning on developing everything from scratch. If you are a software programmer (linux), or a mechanical engineer, and want to help out with the project let me know! I got a site where the progress can be tracked and coordinated,


Sounds like a cool project. Would it help to make a wiki page for it at multi-rotor? --DavidCary 17:12, 9 April 2010 (UTC)

indieVisible -- Originally they started as a nonpolitical open hardware movement for DIY people using advanced minifacturing (3D printing and so on).

Greetz. I linked here from Sparkfun and I guess I will toss this over the wire:

I have here a design for a small power supply board that is intended to be sandwiched on top of a lithium ion cell ( I spec'd a pretty small cell that has a storage capacity of 910mAH). It is thermally controlled and automatically switches off the cell when the charger (USB or wall wart) is connected. I include also a soft-latching power switch, which can be externally connected, and a boost-buck switching converter for driving 3.3V loads.

Here is an image of the schematic:


I do have one question: Barring the fact that I have tried very very hard to get the regulator section layout as tight as possible (The switch has a rate of 1.2MHz), nobody I have seen on the web has indicated any good way to eliminate the AC switching noise from the output. Even bumping the output voltage a bit and feeding an LDO linear regulator seems to bleed the noise right downstream.

Top View:


Bottom View:


These last two prior to the flood-fill on both sides for ground planes.

J.R. Stoner

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