HestiaPi Touch Kit Soldering Guide

Instructions:

This guide describes the steps required to solder and assemble HestiaPi Touch from parts.

We offer all difficult parts as HestiaPi Kit to save you from sourcing all separately.

Assembly with the case and wall is not covered here.

Components:

See BOM for details.

0. RaspberryPi Zero or RaspberryPi Zero W

1. PCB with all SMD parts presoldered (not shown here)2. Touchscreen LCD with protective film to be removed only at the very end3. 5V relays (2pcs) 4. 5V Power supply 5. 1×4 terminal block 6. BME280 sensor 7. 1×4 Female pin headers (2pcs) and 1×4 male-to-male dupont cable 8. Reset button  9. 2×18 male pin header 10. MicroSD card 11. USB WiFi adapter with microUSB converter (unless RaspberryPi Zero W is used)12. Screws and nuts for fixing PCB to case and screws for fixing case to wall

Tools needed:

  1. Your favourite soldering tools
  2. 3mm drill bit
  3. Pliers
  4. Wire cutter

Mechanical preparation:

In order to save space, the black protruding camera connector’s plastic lock needs to be removed by force. Pull by hand one side first, then the other one and remove.

For easier assembly with the case by the supplied screws and nuts a 3mm drill is advised to be used for clearance on the 4 holes on the RaspberryPi.

Soldering order:

  1. Solder the reset button in the RUN pins on RaspberryPi with the button facing the GPIO pins, up. It may touch the two GPIO pins but this will not affect anything. It has a 2.5mm spacing while the RUN pins 2.54mm so it may be a bit tight. Be careful not to bend the legs.
  2. Solder the male 2×18 pin header starting from RaspberryPi’s pin 1, on the left, leaving 4-pin space, on the right, for the reset button to be pressed. Take extra care and the right soldering temperature in order to leave the least solder on the pins. The pins at the bottom will need to enter through the PCB too so if too much solder is used, they will not fit. 
  3. Align, starting from pin 1, the PCB and the RaspberryPi with the male header already soldered. Make sure the 4 fixing holes of the PCB align with the 4 fixing holes of the RaspberryPi. Keep them tightly pressed until you solder 4 pins on left end and 4 pins on the right. Then solder the rest.        
  4. Solder the terminal block, the power supply and the relays, ideally in this order.
  5. If you design your own case and space is plenty, solder the 2 female 1×4 headers on the PCB (labeled BME) and BME sensor. Otherwise bend and solder the dupont 1×4 wire directly to the PCB and BME sensor. VIN to +, GND to -, SCL to SCL and SDA to SDA. The Hex case has a tight sensor compartment at the bottom and some people have pulled the connectors apart by accident stopping temperature readings.  
  6. Align the LCD to pin 1 and press gently all the way down. If you are using the Hex case, the LCD needs to be secured to the cover first.  

Hints and tips

The LCD needs to be connected before powering HestiaPi as it initialises on boot only (otherwise it looks blank-white and touch events do not register) and it may also cause a freeze or reboot due to power spike.

If you cannot control mains, that is having it off during all the time of installation, our advise is to leave the SD card and LCD out, connect all 4 wires (Neutral to N, Line to L, Water to W and Heating to H), partly (not fully) insert the SD and finish off case installation with the LCD attached to the cover. Once all is done, from outside of the case, push first the SD all the way in (it does not lock-click in place) and then insert a non-metallic tool and press the reset button. HestiaPi will boot and in about 10-15sec the LCD will show some of the boot messages.