Re: Hardware cockpit instruments with round displays.
Alan Teeder <[email protected]> Mon, 27 Jul 2026 23:32:51 +0100
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This is a multi-part message in MIME format. --===============6644785351396982803== Content-Type: multipart/alternative; boundary="------------ym8FyS8JU9A8yqSS0HU989Oc" Content-Language: en-GB Content-Transfer-Encoding: 8bit This is a multi-part message in MIME format. --------------ym8FyS8JU9A8yqSS0HU989Oc Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit While I remember, we also used AC synchros to drive instrument pointers. The analogue computers used a stack of potentiometers as multipliers when several quantities needed to be multiplied by the same variable - e.g CL, CD etc. all need to be multiplied by 0.5 x rho x V x S. The first potentiometer on this stack was the servo feedback so that the potentiometer shaft position was equal to the common multiplier that would be used by the remaining potentiometers, which were gain controls within the analogue computer. We would connect a synchro transmitter at the end of the potentiometer drive shaft, and replace all of the instrument mechanics with a synchro receiver which was connected directly to the instrument pointer. These servo multipliers were especially useful for providing ac synchro signals used by the artificial horizon , the compass and autopilots. As well as driving the hardware, the slave potentiometers had sine and cosine shaped resistances, so the analogue computer could multiply by sin or cos of heading, pitch angle, bank angle etc. Apologies for going off subject. In those long lost days the analogue computer ruled the flight simulation world. Alan On 27/07/2026 16:52, Alan Teeder wrote: > > Back in the day when I worked on a full size motion based simulator, > we would make custom 270 degree instruments by taking a suitable 270 > degree volt meter from the stores, repaint the dial black and add > numbers etc using letraset. I built a full set of instruments > (temperature, RPM, EPR etc) for a 4 engine aircraft and drove it with > operational amplifiers taken from our box of ex TSR2 avionics. > Similar meters are available on the Internet at about 15€ each. > > > On 27/07/2026 14:06, James Turner wrote: >> >> >>> On 27 Jul 2026, at 13:16, David Hudach <[email protected]> wrote: >>> >>> These are very interesting and represent genuine alternatives and >>> options. Part of the problem with the "one large monitor" approach >>> that I'm tinkering with is that in order to make the instrument >>> layout match the actual airplane, the monitor is in the way of the >>> yoke mechanism. Running small LCD displays means that the panel >>> layout can be designed in just about any configuration. Again, it's >>> a really nice option. I really like using Raspberry Pi because my >>> surface control interfaces (elevator, rudder, aileron) are written >>> in python and run on the Pi. So it would seem to me that adding >>> input data for instrument displays wouldn't take too much effort. >>> I'm not dismissing the micro-controller route. They each have their >>> place. I like the idea that I can code directly on Pi in my language >>> of choice. >>> >>> Thanks for the additional information, I had no idea these small LCD >>> display components are available. The larger ones cost a bit more >>> but it's definitely not prohibitive. >> >> Yeah this is a big change recently: on AlixExpress you can find >> genuine round and square LCDs with HDMI or similar interfaces for >> decent prices. This would make creating eg a real ISFD: >> >> https://www.aviationhunt.com/b737-integrated-standby-flight-display/ >> >> .. very doable. >> >> Eg: >> >> https://www.aliexpress.com/item/1005006767303668.html?spm=a2g0o.productlist.main.1.2e4bf336i863u0&algo_pvid=4b9728b3-1027-40ad-9c0e-a6500ce62600&algo_exp_id=4b9728b3-1027-40ad-9c0e-a6500ce62600-0&pdp_ext_f=%7B%22order%22%3A%2290%22%2C%22eval%22%3A%221%22%2C%22fromPage%22%3A%22search%22%7D&pdp_npi=6%40dis%21GBP%219.29%219.29%21%21%2112.05%2112.05%21%402103962917851573958806589e0fd5%2112000038231286172%21sea%21UK%21892510239%21X%211%210%21n_tag%3A-29919%3Bd%3Aa355abe0%3Bm03_new_user%3A-29895&curPageLogUid=LO8BF0QKVxW8&utparam-url=scene%3Asearch%7Cquery_from%3A%7Cx_object_id%3A1005006767303668%7C_p_origin_prod%3A >> <https://www.aliexpress.com/item/1005006767303668.html?spm=a2g0o.productlist.main.1.2e4bf336i863u0&algo_pvid=4b9728b3-1027-40ad-9c0e-a6500ce62600&algo_exp_id=4b9728b3-1027-40ad-9c0e-a6500ce62600-0&pdp_ext_f=%7B%22order%22%3A%2290%22%2C%22eval%22%3A%221%22%2C%22fromPage%22%3A%22search%22%7D&pdp_npi=6%40dis%21GBP%219.29%219.29%21%21%2112.05%2112.05%21%402103962917851573958806589e0fd5%2112000038231286172%21sea%21UK%21892510239%21X%211%210%21n_tag%3A-29919%3Bd%3Aa355abe0%3Bm03_new_user%3A-29895&curPageLogUid=LO8BF0QKVxW8&utparam-url=scene%3Asearch%7Cquery_from%3A%7Cx_object_id%3A1005006767303668%7C_p_origin_prod%3A> >> >> (sorry for the long link) >> >> Annoyingly what still seems to be unavailable is a square LCD >> corresponding to the old square displays used in the >> 747-400/7373NG/777 era cockpits: thus would be something like an 8” >> ‘square’ LCD and the largest truly square displays seem to max out at >> 4” like the one above. >> >> Kind regards, >> James >> >> >> >> _______________________________________________ >> Flightgear-devel mailing list >> [email protected] >> https://lists.sourceforge.net/lists/listinfo/flightgear-devel > > > _______________________________________________ > Flightgear-devel mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/flightgear-devel --------------ym8FyS8JU9A8yqSS0HU989Oc Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: 8bit <!DOCTYPE html> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> </head> <body> <p>While I remember, we also used AC synchros to drive instrument pointers. The analogue computers used a stack of potentiometers as multipliers when several quantities needed to be multiplied by the same variable - e.g CL, CD etc. all need to be multiplied by 0.5 x rho x V x S. The first potentiometer on this stack was the servo feedback so that the potentiometer shaft position was equal to the common multiplier that would be used by the remaining potentiometers, which were gain controls within the analogue computer. We would connect a synchro transmitter at the end of the potentiometer drive shaft, and replace all of the instrument mechanics with a synchro receiver which was connected directly to the instrument pointer. </p> <p>These servo multipliers were especially useful for providing ac synchro signals used by the artificial horizon , the compass and autopilots. As well as driving the hardware, the slave potentiometers had sine and cosine shaped resistances, so the analogue computer could multiply by sin or cos of heading, pitch angle, bank angle etc.</p> <p>Apologies for going off subject. In those long lost days the analogue computer ruled the flight simulation world.</p> <p>Alan</p> <div class="moz-cite-prefix">On 27/07/2026 16:52, Alan Teeder wrote:<br> </div> <blockquote type="cite" cite="mid:[email protected]"> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <p>Back in the day when I worked on a full size motion based simulator, we would make custom 270 degree instruments by taking a suitable 270 degree volt meter from the stores, repaint the dial black and add numbers etc using letraset. I built a full set of instruments (temperature, RPM, EPR etc) for a 4 engine aircraft and drove it with operational amplifiers taken from our box of ex TSR2 avionics. Similar meters are available on the Internet at about 15€ each.</p> <p><br> </p> <div class="moz-cite-prefix">On 27/07/2026 14:06, James Turner wrote:<br> </div> <blockquote type="cite" cite="mid:[email protected]"> <meta http-equiv="content-type" content="text/html; charset=UTF-8"> <br id="lineBreakAtBeginningOfMessage"> <div><br> <blockquote type="cite"> <div>On 27 Jul 2026, at 13:16, David Hudach <a class="moz-txt-link-rfc2396E" href="mailto:[email protected]" moz-do-not-send="true"><[email protected]></a> wrote:</div> <br class="Apple-interchange-newline"> <div> <meta charset="UTF-8"> <div class="gmail_default" style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-line: none; text-decoration-thickness: auto; text-decoration-style: solid; font-size: small;">These are very interesting and represent genuine alternatives and options. Part of the problem with the "one large monitor" approach that I'm tinkering with is that in order to make the instrument layout match the actual airplane, the monitor is in the way of the yoke mechanism. Running small LCD displays means that the panel layout can be designed in just about any configuration. Again, it's a really nice option. I really like using Raspberry Pi because my surface control interfaces (elevator, rudder, aileron) are written in python and run on the Pi. So it would seem to me that adding input data for instrument displays wouldn't take too much effort. I'm not dismissing the micro-controller route. They each have their place. I like the idea that I can code directly on Pi in my language of choice.</div> <div class="gmail_default" style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-line: none; text-decoration-thickness: auto; text-decoration-style: solid; font-size: small;"><br> </div> <div class="gmail_default" style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-line: none; text-decoration-thickness: auto; text-decoration-style: solid; font-size: small;">Thanks for the additional information, I had no idea these small LCD display components are available. The larger ones cost a bit more but it's definitely not prohibitive.</div> </div> </blockquote> </div> <br> <div>Yeah this is a big change recently: on AlixExpress you can find genuine round and square LCDs with HDMI or similar interfaces for decent prices. This would make creating eg a real ISFD:</div> <div><br> </div> <div><span class="Apple-tab-span" style="white-space:pre"> </span><a href="https://www.aviationhunt.com/b737-integrated-standby-flight-display/" moz-do-not-send="true" class="moz-txt-link-freetext">https://www.aviationhunt.com/b737-integrated-standby-flight-display/</a></div> <div><br> </div> <div>.. very doable.</div> <div><br> </div> <div>Eg:</div> <div><br> </div> <div><span class="Apple-tab-span" style="white-space:pre"> </span><a href="https://www.aliexpress.com/item/1005006767303668.html?spm=a2g0o.productlist.main.1.2e4bf336i863u0&algo_pvid=4b9728b3-1027-40ad-9c0e-a6500ce62600&algo_exp_id=4b9728b3-1027-40ad-9c0e-a6500ce62600-0&pdp_ext_f=%7B%22order%22%3A%2290%22%2C%22eval%22%3A%221%22%2C%22fromPage%22%3A%22search%22%7D&pdp_npi=6%40dis%21GBP%219.29%219.29%21%21%2112.05%2112.05%21%402103962917851573958806589e0fd5%2112000038231286172%21sea%21UK%21892510239%21X%211%210%21n_tag%3A-29919%3Bd%3Aa355abe0%3Bm03_new_user%3A-29895&curPageLogUid=LO8BF0QKVxW8&utparam-url=scene%3Asearch%7Cquery_from%3A%7Cx_object_id%3A1005006767303668%7C_p_origin_prod%3A" moz-do-not-send="true">https://www.aliexpress.com/item/1005006767303668.html?spm=a2g0o.productlist.main.1.2e4bf336i863u0&algo_pvid=4b9728b3-1027-40ad-9c0e-a6500ce62600&algo_exp_id=4b9728b3-1027-40ad-9c0e-a6500ce62600-0&pdp_ext_f=%7B%22order%22%3A%2290%22%2C%22eval%22%3A%221%22%2C%22fromPage%22%3A%22search%22%7D&pdp_npi=6%40dis%21GBP%219.29%219.29%21%21%2112.05%2112.05%21%402103962917851573958806589e0fd5%2112000038231286172%21sea%21UK%21892510239%21X%211%210%21n_tag%3A-29919%3Bd%3Aa355abe0%3Bm03_new_user%3A-29895&curPageLogUid=LO8BF0QKVxW8&utparam-url=scene%3Asearch%7Cquery_from%3A%7Cx_object_id%3A1005006767303668%7C_p_origin_prod%3A</a></div> <div><br> </div> <div>(sorry for the long link)</div> <div><br> </div> <div>Annoyingly what still seems to be unavailable is a square LCD corresponding to the old square displays used in the 747-400/7373NG/777 era cockpits: thus would be something like an 8” ‘square’ LCD and the largest truly square displays seem to max out at 4” like the one above.</div> <div><br> </div> <div>Kind regards,</div> <div>James</div> <div><br> </div> <br> <fieldset class="moz-mime-attachment-header"></fieldset> <br> <fieldset class="moz-mime-attachment-header"></fieldset> <pre wrap="" class="moz-quote-pre">_______________________________________________ Flightgear-devel mailing list <a class="moz-txt-link-abbreviated moz-txt-link-freetext" href="mailto:[email protected]" moz-do-not-send="true">[email protected]</a> <a class="moz-txt-link-freetext" href="https://lists.sourceforge.net/lists/listinfo/flightgear-devel" moz-do-not-send="true">https://lists.sourceforge.net/lists/listinfo/flightgear-devel</a> </pre> </blockquote> <br> <fieldset class="moz-mime-attachment-header"></fieldset> <br> <fieldset class="moz-mime-attachment-header"></fieldset> <pre wrap="" class="moz-quote-pre">_______________________________________________ Flightgear-devel mailing list <a class="moz-txt-link-abbreviated" href="mailto:[email protected]">[email protected]</a> <a class="moz-txt-link-freetext" href="https://lists.sourceforge.net/lists/listinfo/flightgear-devel">https://lists.sourceforge.net/lists/listinfo/flightgear-devel</a> </pre> </blockquote> </body> </html> --------------ym8FyS8JU9A8yqSS0HU989Oc-- --===============6644785351396982803== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline --===============6644785351396982803== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ Flightgear-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/flightgear-devel --===============6644785351396982803==--