Repairing a Nikon D80 with ERR message TRACK TOP
Publicado el 4th Diciembre, 2021 por KaRMaN. Archivado en Cacharros, Electrónica, Hardware.
Leido 25,815 veces. Comments Off

Initially introduced at $999 body only this was a prosumer camera back in 2006. Later years and up today photography comunity members started to report a ERR message in their cameras top display (in the shutter speed field). This error is commonly associated to the mechanical parts of the camera (shutter, diaphragm and mirror) being not properly in sync.

I have already fixed 3 cameras with these flaws. These cameras where brougth to me as for parts/teardowns so I decided to publish a small guideline on how to fix them.

Nikon D80 and the main mechanics

Nikon D80 and the main mechanics

Seems that this specific model of Nikon had two major flawn that made the mechanics out of sync. Maybe the fault comes from the design, maybe comes from quality control. The flawns are:

Main motor pinion gets broken. This makes the pinion too loose so the motor spins without transmiting it’s force to the mecanism and rotating in void. The main electronics detects no action in it’s sensors despite givin the command to spin the motor, hence produces the ERR message. This is fixable by carefully removing the pinion, putting a smal drop of SuperGlue in the motors shaft tip then pushing back the pinion.

Nikon D80 main motor pinion broken in half

Nikon D80 main motor pinion broken in half

Mechanics encoder loses one brush fixing. The mechanic rotatory enconder is the electronics main sensor of the mecanics position and travel. It’s made of a gear that has a fixed brushes against a PCB board where makes it’s contact. The brushes are fixed by a plastic welding that brokes with passing time. The brushes then missaling or makes no contact at all. Electronics loses perception of the mechanics travel and position and then drops the fatal ERR message. This can be fixed with a small drop of superglue in the affected/broken plastic fixing (in this photo, the right side one).

Mechanics rotatory encoder with one broken/loose plastic fixing.

Mechanics rotatory encoder with one broken/loose plastic fixing.

I recommend to let dry the superglue at least 1  hour before trying the fix. You can start assembling the camera inmediatly but is best for all to let it totally dry before inserting a charged battery to try it out.

Any of these flaws renders the camera unusable. Fortunally both flaws are relative easy to fix, but both requires a lot of careful dissasembly to be able to get to the afected parts. I recommend to follow the help this Nikon D80 service manual and use a welder when the disassembly requires to unsolder some wires.

Nikon D80 main mechanics, motor removed. The main encoder can be seen below, being the grey gear.

Nikon D80 main mechanics, motor removed. The main encoder can be seen below, being the grey gear.

Publicado el 16th Agosto, 2021 por KaRMaN. Archivado en Arduino, Electrónica, Hardware.
Leido 32,214 veces. 3 comentarios archivados.

This is my last week project: a Simple Yet Powerful Handheld CO2 Meter. SYPHCOM (name in progress ..)

The use for a portable CO2 meter is to be able to measure air quality in closed spaces (i.e. the office). The higher the number (usually above 1200~1500) the worst ventilation, which means higher chances to get
the Covid-19.

CO2 Meter Front View

CO2 Meter Front View

With this is possible to know when is time to open the windows and ventilate.

It’s main guts are:

Back view of handmade CO2 meter

Back view of handmade CO2 meter

The capacitor stands for when the CO2 sensor does a read cycle (every 2s): both the display and the SenseAir S8 uses so much power that you can see the display and leds in the Arduino Pro Micro sighly dim off when powered from standard USB 0.5A when a read is made in the SenseAir CO2 Sensor. Without the capacitor, the arduino can’t stand for the display refresh and does a glitch in the display.

BCO2 Meter Glitch

CO2 Meter glitch

Also there’s a UDN2981A source driver to drive the columns in the HDSP-2000 display and a small momentary press button with 10K pull down resistor to launch sensor callibration if pressed on powerup (use with caution!!).

CO2 Meter first working stage

CO2 Meter first working stage

The components that makes it portable are:

  • Lithium battery charger (Like this one).
  • Recycled Li-Po cell (250mAh)
  • Pololu s7v8a adjustable step-up DC-DC (adjusted to 5V).
  • Switch.
Making CO2 Meter porable with lipo charger and battery

Making CO2 Meter porable with lipo charger and battery

I use the same components to make projects portables. The good thing about the pololu s7v8a is that it is both a step-up and a step-down DC-DC converter. This is handful if a project work 3.3v as it will give 3.3v always even if the battery is reading 3.0v. Unfortunally the recicled 250mAh battery is not much for the power needs so only lasts 30m on thi battery cell.

CO2 Arduino HDSP-2000 SenseAir Schematic

CO2 Arduino HDSP-2000 SenseAir Schematic

Code available here.

In the video the leds seems to be dimmer than they really are because of the high light, but actually they are pretty much visible.

Overall all makes a nice looking portable and easy to use CO2 meter and Covid prevention tool in closed spaces.

Omega2+ minidock and Oled custom enclosure. TRACK TOP
Publicado el 10th Septiembre, 2020 por KaRMaN. Archivado en Sin categoria.
Leido 34,781 veces. 4 comentarios archivados.

I’ve had this Omega2+ with minidock and soldered Oled SDD1306 lying around naked and decided to make a 3D printed custom enclosure for it.

Both halves snaps together to keep it closed.

WiFi Scanner Keychain TRACK TOP
Publicado el 9th Septiembre, 2020 por KaRMaN. Archivado en Sin categoria.
Leido 26,853 veces. Comments Off

I recently came across with moononournation’s libraries and code on Arduino IDE for ESP8266 and ESP32, which includes a demo of WiFi 2.4G air scanner.

As iOS user I can not have a WiFi Explorer so having this keychain hanging in my backpack was a nice idea. However moononournation did a tutorial and printer STL files for a TTGO VT7 v1.0 that is no longer available, so I designed my own enclosure for a TTGO T7 v1.4.

Link to the file here.

Publicado el 29th Julio, 2020 por KaRMaN. Archivado en Sin categoria.
Leido 32,581 veces. 6 comentarios archivados.

When I contracted my internet line with spanish ISP Pepephone they installed me a ZTE F680 router with embedded ONU/ONT. I didn’t wanted the router thing so I hacked it to achieve the ONU/ONT password and replaced with a classic ZTE F601.

Now I finally managed to get rid of the ZTE F601 by using a SFP with integrated ONU/ONT. The SFP I bought is DFP-34X-2C2 but DFP-34G-2C2 model should work as well.



This is an ARM v7 (ZX279125) running at 600Mhz and nearly 1200 bogomips, 32Mb integrated RAM and 16Mb of external (SPI?) flash (source) running linux ZTE flavour 2.6.32 in a SFP form factor. PDF

To be able to configure it there has to be some link in the optical connection, otherwise the SFP interface in your switch/router might not linkup and the SFP internal IP might not be reachable.

The default connection info is as follows:

  • IP:
  • VLAN: 1
  • URL:
  • User: admin
  • Pass: admin

In its web page you can configure PON settings and even routing mode. By default, there is no WAN connection (this means there’s no routing mode, only bridge with all vlans through the SFP interface port). You can make the SFP a router to route you house/office traffic by making a WAN connection but I prefer to keep it as bridge.

Once in the web configuration page we can configure LOID, SN and their passwords as per our ISP requirements:

DFP-34G-2C2 LOID web onu ont

DFP-34G-2C2 LOID web

DFP-34G-2C2 SN web

DFP-34G-2C2 SN web

There is also telnet access with the following credentials:

  • User: root
  • Pass: Pon521

Telnet access is for linux advanced users and is not recomended to tamper with.

I bougth mine here:

I have this SFP directly plugged to my C2960G switch and my router is a Debian virtual machine inside a synology DS218+ NAS which receivec VLAN20 traffic from the ONU/ONT through the switch and then the VM routers the traffic to VLAN1.