# Taktile Simple Pressure Sensor **URL:** \ **Category:** DIY STUFF\ **Created:** [September 14, 2020, 8:28am UTC](https://lookmumnocomputer.discourse.group/t/taktile-simple-pressure-sensor/1801 "2020-09-14T08:28:27Z")\ **Posts on this page:** 13\ **Page:** 1
**Author:** ![Mcshafty](https://avatars.discourse-cdn.com/v4/letter/m/f4b2a3/32.png) [@Mcshafty](https://lookmumnocomputer.discourse.group/u/Mcshafty)\ **Post date:** [September 14, 2020, 8:28am UTC](https://lookmumnocomputer.discourse.group/t/taktile-simple-pressure-sensor/1801/1 "2020-09-14T08:28:27Z")
Today I built the Taktile from Synth DIY Guy’s YouTube clip. [https://youtu.be/DT6nZsixP0M](https://youtu.be/DT6nZsixP0M) Great fun, especially if you lick it ![IMG20200914180550](https://global.discourse-cdn.com/free1/uploads/lookmumnocomputer/original/2X/6/6ddea028f13cf51079f0402b2e6b2224170ea538.jpeg) Out of interest, it took a couple of hours for the copper the etch away in the ferric chloride solution I mixed. Is that normal? ---
**Author:** ![fredrik](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/fredrik/32/682_2.png) [@fredrik](https://lookmumnocomputer.discourse.group/u/fredrik)\ **Post date:** [September 14, 2020, 10:12am UTC](https://lookmumnocomputer.discourse.group/t/taktile-simple-pressure-sensor/1801/2 "2020-09-14T10:12:45Z")
> [@Mcshafty](#): > > Is that normal? It was ages since I used ferric chloride, but it sounds a bit high. But etching time depends on temperature and you also need to agitate the container now and then to make sure the surface is exposed to fresh etchant. ---
**Author:** ![Mcshafty](https://avatars.discourse-cdn.com/v4/letter/m/f4b2a3/32.png) [@Mcshafty](https://lookmumnocomputer.discourse.group/u/Mcshafty)\ **Post date:** [September 14, 2020, 11:12am UTC](https://lookmumnocomputer.discourse.group/t/taktile-simple-pressure-sensor/1801/3 "2020-09-14T11:12:03Z")
Thanks. Agitating did help - and the solution was cold. This was my second go at etching. First time I didn’t leave it in the ferric chloride long enough - I just thought the board underneath the copper was a pale pink colour. That led to some head sctratching with the multimeter! ---
**Author:** ![telec16](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/telec16/32/4510_2.png) [@telec16](https://lookmumnocomputer.discourse.group/u/telec16)\ **Post date:** [September 14, 2020, 1:21pm UTC](https://lookmumnocomputer.discourse.group/t/taktile-simple-pressure-sensor/1801/4 "2020-09-14T13:21:01Z")
Did you brush up the copper before etching? It usually works better if it’s not oxidized. ---
**Author:** ![Mcshafty](https://avatars.discourse-cdn.com/v4/letter/m/f4b2a3/32.png) [@Mcshafty](https://lookmumnocomputer.discourse.group/u/Mcshafty)\ **Post date:** [September 14, 2020, 1:52pm UTC](https://lookmumnocomputer.discourse.group/t/taktile-simple-pressure-sensor/1801/5 "2020-09-14T13:52:23Z")
No, I only gave it a good wipe with isopropyl alcohol to clean the surface before drawing on the two tracks with a Sharpie. Next time I’ll try buffing the copper with some wirewool first. ---
**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:** [September 14, 2020, 5:01pm UTC](https://lookmumnocomputer.discourse.group/t/taktile-simple-pressure-sensor/1801/6 "2020-09-14T17:01:32Z")
> [@Mcshafty](#): > > Great fun, especially if you lick it and you get an additional prickly taste, unless you wash the board after etching … To warm up the etching solution I once used an electric iron held upside down by a vice. I put a glass tray with the etching fluid on top of it. The power to the iron I reduced using a dimmer circuit for a light bulb. The fluid got warm but not hot in this way. Worked like a charm! ---
**Author:** ![eric](https://avatars.discourse-cdn.com/v4/letter/e/898d66/32.png) [@eric](https://lookmumnocomputer.discourse.group/u/eric)\ **Post date:** [September 14, 2020, 5:05pm UTC](https://lookmumnocomputer.discourse.group/t/taktile-simple-pressure-sensor/1801/7 "2020-09-14T17:05:31Z")
An old iron upside-down in a wise si great too. Has integrated “dimmer”. ---
**Author:** ![Mcshafty](https://avatars.discourse-cdn.com/v4/letter/m/f4b2a3/32.png) [@Mcshafty](https://lookmumnocomputer.discourse.group/u/Mcshafty)\ **Post date:** [September 15, 2020, 3:56am UTC](https://lookmumnocomputer.discourse.group/t/taktile-simple-pressure-sensor/1801/8 "2020-09-15T03:56:52Z")
After I’d finished the ironing I drew up the layout ![tttttouchmebyppp](https://global.discourse-cdn.com/free1/uploads/lookmumnocomputer/original/2X/e/e7b227f9a3a33cec33956b823f8f6c1bfff12179.png) I added an on/off switch to save the batteries and put a red led under the etched PCB for an eerie glow. If I did it again I’d use a smaller resistor before the led to make it brighter. ---
**Author:** ![Mcshafty](https://avatars.discourse-cdn.com/v4/letter/m/f4b2a3/32.png) [@Mcshafty](https://lookmumnocomputer.discourse.group/u/Mcshafty)\ **Post date:** [September 20, 2020, 8:46am UTC](https://lookmumnocomputer.discourse.group/t/taktile-simple-pressure-sensor/1801/9 "2020-09-20T08:46:49Z")
I just found this nifty AA to 12v battery adaptor. Anybody see any issues using this to replace the 9v battery? ![160059146265178897320](https://global.discourse-cdn.com/free1/uploads/lookmumnocomputer/original/2X/6/667149c3bfe15c377b3bff8bb11ec4e88f18a3e6.jpeg) ---
**Author:** ![Mcshafty](https://avatars.discourse-cdn.com/v4/letter/m/f4b2a3/32.png) [@Mcshafty](https://lookmumnocomputer.discourse.group/u/Mcshafty)\ **Post date:** [September 20, 2020, 11:18am UTC](https://lookmumnocomputer.discourse.group/t/taktile-simple-pressure-sensor/1801/10 "2020-09-20T11:18:58Z")
Thought wtf and tried it anyway. Works a treat with 12v. And the weight of the AA batteries adds a nice bit of heft to the case. ---
**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:** [September 20, 2020, 12:22pm UTC](https://lookmumnocomputer.discourse.group/t/taktile-simple-pressure-sensor/1801/11 "2020-09-20T12:22:05Z")
> [@Mcshafty](#): > > If I did it again I’d use a smaller resistor before the led to make it brighter. Is there a reason the PCB’s connected to the LED and not to the battery? How much resistance do you get across the PCB? If I lick two fingers and hold multimeter probes between them I get about 1 or 2 M. If you get something like that, then with the pot turned all the way left, 2V drop across the LED, and a 100k load on the CV, I’d expect the CV to go from ~0V to about 2((100k||10k)/((100k||10k)+1M)) ~ 0.018V. Very small. But if the PCB connected to the other end of the resistor you’d get (with 12V battery) about 6 times higher CV, 0.11 V. Still pretty small. Using a 100k pot would increase that. Or am I for some reason seriously overestimating the PCB resistance? ---
**Author:** ![Mcshafty](https://avatars.discourse-cdn.com/v4/letter/m/f4b2a3/32.png) [@Mcshafty](https://lookmumnocomputer.discourse.group/u/Mcshafty)\ **Post date:** [September 20, 2020, 1:31pm UTC](https://lookmumnocomputer.discourse.group/t/taktile-simple-pressure-sensor/1801/12 "2020-09-20T13:31:08Z")
Gee, that’s a bit to consider. I only wired the led the way I did because it seems to work - and I am totally bluffing my way so thanks for the hints. Any improvements and suggestions are much appreciated. I’ll have a chance to do some probing with a multimeter in a day or so and will try connecting the resistor to the other side of the board. There was no switch or led in Synth DIY Guy’s example vid. I just knew that I would forget to disconnect the battery without them. ---
**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:** [September 20, 2020, 2:17pm UTC](https://lookmumnocomputer.discourse.group/t/taktile-simple-pressure-sensor/1801/13 "2020-09-20T14:17:25Z")
> [@Mcshafty](#): > > will try connecting the resistor to the other side of the board. Board to the other side of the resistor, rather — the suggestion is that the board connect direct to the battery (or rather to the switch connected to the battery). Just move that one wire, red in your diagram.