Reference

Node Reference

Every node available in the BLUEHASH editor — ports, config fields, notes, and examples.

triggerstringnumberfloatbooleanokerrorneutralany

6 nodes

Flow control

Sequencing, timing, branching, and repeating

6 nodes

Display

OLED text, menus, values, and notifications

1 nodes

Input

Physical button presses

10 nodes

GPIO / Hardware

Digital, analog, PWM, IR, RF, camera

9 nodes

Connectivity

WiFi, web server, HTTP, MQTT

5 nodes

Data / Logic

Variables, math, storage, scaling

6 nodes

System

Sleep, restart, logging, custom code

Flow control

Sequencing, timing, branching, and repeating

start

Start

Entry point of every flow. Fires boot on power-up. Every flow must have exactly one Start node.

Ports

Name	Dir	Type	Description
boot	OUT →	trigger	Fires once when the device powers on
wake	OUT →	trigger	Fires when waking from deep sleep

Notes

Every flow must have exactly one Start node
boot and wake are separate — use wake to restore state after deep sleep

end

End

Terminates a flow branch. Has no effect at runtime — used as a visual terminator.

Ports

Name	Dir	Type	Description
trigger	← IN	trigger	Receives any trigger and does nothing

delay

Delay

Blocks execution for a fixed duration, then fires done.

Ports

Name	Dir	Type	Description
trigger	← IN	trigger	Start the delay
done	OUT →	trigger	Fires after duration has elapsed

Config

Key	Widget	Default	Description
duration	number	1000	Wait time in milliseconds

Example

// Blink: wait 500ms between on/off
[digital_write HIGH] → done → [delay 500] → done → [digital_write LOW]

timer

Timer

Fires tick on a repeating interval. Non-blocking — runs alongside other nodes each loop iteration.

Ports

Name	Dir	Type	Description
start	← IN	trigger	Enable the timer
stop	← IN	trigger	Disable the timer
tick	OUT →	trigger	Fires every interval ms

Config

Key	Widget	Default	Description
interval	number	1000	Time between ticks in milliseconds
autoStart	toggle	true	Start ticking immediately on boot without needing a start trigger

Notes

Timer runs in tick() — it is non-blocking and never delays other nodes
autoStart=true means the timer fires from boot with no wiring needed

Example

// Read sensor every 2 seconds
[timer interval=2000] → tick → [analog_read]

condition

Condition

Compares two float values (A op B) and routes flow to true or false output.

Ports

Name	Dir	Type	Description
run	← IN	trigger	Evaluate the condition
a	← IN	number	Left-hand value
b	← IN	number	Right-hand value
true	OUT →	trigger	Fires when condition is true
false	OUT →	trigger	Fires when condition is false

Config

Key	Widget	Default	Description
operator	select	==	Comparison: ==, !=, >, <, >=, <=

Example

// Alert if voltage > 3.0V
[analog_read] → voltage → [condition A>3.0] → true → [notification "High voltage"]

loop

Loop

Fires each(index) N times in sequence, then fires done.

Ports

Name	Dir	Type	Description
run	← IN	trigger	Start the loop
each	OUT →	number	Fires for each iteration with current index (0-based)
done	OUT →	trigger	Fires after all iterations complete

Config

Key	Widget	Default	Description
count	number	10	Number of iterations

Notes

Loop is blocking — the device cannot do anything else during iteration
Use timer + counter for non-blocking repeat

Display

OLED text, menus, values, and notifications

show_text

Show text

Prints static text at a pixel position on the OLED. Optionally clears the screen first.

Ports

Name	Dir	Type	Description
trigger	← IN	trigger	Draw the text
done	OUT →	trigger	Fires after text is drawn

Config

Key	Widget	Default	Description
text	text		Text to display
x	number	0	X pixel position (0 = left edge)
y	number	0	Y pixel position (0 = top edge)
fontSize	select	small	small (5×7) \| medium (8×8) \| large (10×20)
clear	toggle	false	Clear screen before drawing

Example

// Show IP on boot
[wifi_connect] → ip → [show_text "IP: " x=0 y=0]

Shows a scrollable menu on OLED. Reads Up/Down/OK/Back buttons internally — no button_press node needed.

Ports

Name	Dir	Type	Description
show	← IN	trigger	Display the menu and start listening for input
option_0…N	OUT →	trigger	One output per item — fires when user selects that item
back	OUT →	trigger	Fires when user presses Back

Config

Key	Widget	Default	Description
title	text	—	Header text shown above items
items	itemlist	—	List of menu item labels

Notes

Menu reads buttons itself — do NOT add a button_press node alongside it
Up/Down scroll, OK selects, Back fires the back output
Scroll indicator appears automatically when items > 4
Pressing Back from any option wires back to re-show the menu

Example

// Main menu → 3 options
[start] → boot → [menu "MAIN"]
  option_0 → [show_text "Blink"]
  option_1 → [ir_send]
  option_2 → [show_text "Info"]
  back     → [menu "MAIN"] (re-show)

show_value

Show value

Displays a labelled numeric value in large font. Good for live sensor readings.

Ports

Name	Dir	Type	Description
trigger	← IN	trigger	Refresh the display with the current value
value	← IN	number	Float value to display — triggers refresh automatically
done	OUT →	trigger	Fires after display is updated

Config

Key	Widget	Default	Description
label	text	Value	Label shown above the value
unit	text		Unit suffix shown after the number (e.g. °C, V, %)
decimals	number	1	Decimal places to display

Example

// Live temperature display
[timer 2s] → tick → [analog_read] → voltage → [show_value label="Temp" unit="V"]

progress_bar

Progress bar

Draws a progress bar 0–100%. Fires full when value reaches 100.

Ports

Name	Dir	Type	Description
trigger	← IN	trigger	Refresh the bar
value	← IN	number	0–100 — triggers refresh automatically when wired
done	OUT →	trigger	Fires after drawing
full	OUT →	trigger	Fires when value reaches 100

Config

Key	Widget	Default	Description
label	text		Label shown above the bar
height	number	8	Bar height in pixels

notification

Notification

Shows a popup message and waits for OK/Back or timeout. Blocking.

Ports

Name	Dir	Type	Description
trigger	← IN	trigger	Show the notification
ok	OUT →	trigger	Fires when user presses OK
dismissed	OUT →	trigger	Fires when user presses Back or timeout expires

Config

Key	Widget	Default	Description
message	text	—	Message text to display
duration	number	2000	Auto-dismiss after ms (0 = wait forever)

clear_screen

Clear screen

Blanks the OLED.

Ports

Name	Dir	Type	Description
trigger	← IN	trigger	Clear the screen
done	OUT →	trigger	Fires after clearing

Config

Key	Widget	Default	Description
fill	select	black	black (blank) \| white (all pixels on)

Input

Physical button presses

button_press

Button press

Detects physical button presses on board-defined pins and fires per-button outputs.

Ports

Name	Dir	Type	Description
ok	OUT →	trigger	OK button pressed
back	OUT →	trigger	Back button pressed
up	OUT →	trigger	Up button pressed
down	OUT →	trigger	Down button pressed
btn1	OUT →	trigger	Button 1 pressed
btn2	OUT →	trigger	Button 2 pressed

Config

Key	Widget	Default	Description
debounce	number	50	Debounce window in ms

Notes

Pin assignments come from bh_hal.h — they are board-specific
Pins defined as -1 for a board are silently skipped
Do NOT use button_press alongside a menu node — menu reads buttons itself
ESP32-CAM only has OK (GPIO 13) and Back (GPIO 0 / IO0 button)

GPIO / Hardware

Digital, analog, PWM, IR, RF, camera

digital_write

Digital write

Sets a GPIO pin HIGH or LOW.

Ports

Name	Dir	Type	Description
trigger	← IN	trigger	Apply the pin state
done	OUT →	trigger	Fires after pin is set

Config

Key	Widget	Default	Description
pin	pin	—	GPIO pin number
state	select	HIGH	HIGH or LOW

digital_read

Digital read

Reads a GPIO pin and fires high or low output.

Ports

Name	Dir	Type	Description
trigger	← IN	trigger	Perform the read
state	OUT →	boolean	Current pin state (true=HIGH)
high	OUT →	trigger	Fires if pin is HIGH
low	OUT →	trigger	Fires if pin is LOW

Config

Key	Widget	Default	Description
pin	pin	—	GPIO pin number
pullMode	select	INPUT_PULLUP	INPUT \| INPUT_PULLUP \| INPUT_PULLDOWN

analog_read

Analog read

Reads an ADC pin. Returns both raw 12-bit value (0–4095) and converted voltage (0–3.3V).

Ports

Name	Dir	Type	Description
trigger	← IN	trigger	Perform the read
raw	OUT →	number	0–4095 ADC value
voltage	OUT →	number	0.0–3.3 calculated voltage

Config

Key	Widget	Default	Description
pin	pin	—	ADC-capable GPIO pin

Notes

Uses 11dB attenuation — full 0–3.3V range
ESP32 ADC is non-linear near 0V and 3.3V — use map_scale for calibration

pwm_output

PWM output

Outputs a PWM signal — for LED dimming, motor speed, servo control.

Ports

Name	Dir	Type	Description
trigger	← IN	trigger	Apply PWM settings
done	OUT →	trigger	Fires after PWM is applied

Config

Key	Widget	Default	Description
pin	pin	—	PWM-capable GPIO pin
duty	number	128	Duty cycle 0–255
freq	number	1000	Frequency in Hz

pin_trigger

Pin trigger

Fires on GPIO edge via hardware interrupt. Non-blocking — works alongside everything else.

Ports

Name	Dir	Type	Description
rising	OUT →	trigger	Fires on LOW→HIGH edge
falling	OUT →	trigger	Fires on HIGH→LOW edge
change	OUT →	trigger	Fires on any edge
state	OUT →	boolean	Current pin state

Config

Key	Widget	Default	Description
pin	pin	—	GPIO pin to watch
mode	select	CHANGE	RISING \| FALLING \| CHANGE

Notes

Uses hardware interrupt (IRAM_ATTR) — minimal latency
Sets INPUT_PULLUP automatically

ir_receive

IR receive

Decodes IR signals from any remote. Outputs the protocol name and raw code.

Ports

Name	Dir	Type	Description
received	OUT →	trigger	Fires when a valid IR code is received
protocol	OUT →	string	Protocol name e.g. NEC, SONY, RC5
code	OUT →	number	Raw decoded IR code

Config

Key	Widget	Default	Description
pin	pin	—	IR receiver data pin (connect to TSOP382x)
timeout	number	15	Gap timeout in ms — default suits most remotes

Notes

Supports NEC, SONY, RC5, RC6, Samsung, LG, and 20+ more protocols via IRremoteESP8266

ir_send

IR send

Transmits an IR code at 38kHz carrier.

Ports

Name	Dir	Type	Description
trigger	← IN	trigger	Send the IR code
sent	OUT →	trigger	Fires after transmission completes

Config

Key	Widget	Default	Description
pin	pin	—	IR LED pin (via NPN transistor for range)
protocol	select	NEC	NEC \| SONY \| RC5 \| RC6 \| Samsung \| LG
code	text	—	IR code in hex e.g. 0x20DF10EF
bits	number	32	Code bit length

rf_receive

RF receive

Receives 433MHz RF codes from remote controls and switches.

Ports

Name	Dir	Type	Description
received	OUT →	trigger	Valid code received
code	OUT →	number	Decoded RF code
protocol	OUT →	number	RF protocol number
bitlength	OUT →	number	Code bit length

Config

Key	Widget	Default	Description
pin	pin	—	RF receiver DATA pin

rf_send

RF send

Transmits a 433MHz RF code — controls remote sockets, gates, alarm panels.

Ports

Name	Dir	Type	Description
trigger	← IN	trigger	Transmit the code
sent	OUT →	trigger	Fires after transmission

Config

Key	Widget	Default	Description
pin	pin	—	RF transmitter DATA pin
code	number	—	RF code to send
bitLength	number	24	Code bit length
protocol	number	1	RF protocol (1 is most common)
pulseLength	number	350	Pulse width in µs
repeat	number	10	Transmission repeat count

camera_capture

Camera capture

Initializes the OV2640/OV5640 camera and captures a single JPEG frame into memory.

Ports

Name	Dir	Type	Description
trigger	← IN	trigger	Capture a frame
done	OUT →	trigger	Frame captured successfully
imagedata	OUT →	any	BHFrame* pointer — connect to SD write or custom_code
width	OUT →	number	Frame width in pixels
height	OUT →	number	Frame height in pixels
error	OUT →	error	Camera not ready or capture failed

Config

Key	Widget	Default	Description
resolution	select	QVGA (320x240)	QQVGA \| QVGA \| VGA \| SVGA \| XGA \| UXGA
format	select	JPEG	JPEG \| RGB565 \| Grayscale
quality	number	12	JPEG quality 4–63 (lower = smaller file)
hmirror	toggle	false	Flip image horizontally
vflip	toggle	false	Flip image vertically

Notes

Cannot be used in the same flow as cam_web — both call bh_cam_init() and will conflict
Use camera_capture to save frames to SD card
Use cam_web to serve frames over HTTP to a browser
PSRAM required for VGA and above — ESP32-CAM has PSRAM, plain ESP32 does not

Connectivity

WiFi, web server, HTTP, MQTT

wifi_connect

WiFi connect

Connects to an existing WiFi access point (STA mode). Shows progress on OLED.

Ports

Name	Dir	Type	Description
trigger	← IN	trigger	Start connecting
connected	OUT →	ok	Successfully connected
ip	OUT →	string	Assigned IP address string
failed	OUT →	error	Connection failed or timed out
timeout	OUT →	neutral	Timeout elapsed without connecting

Config

Key	Widget	Default	Description
ssid	text	—	WiFi network name
password	text	—	WiFi password
timeout	number	10000	Connection timeout in ms

Notes

Cannot be used in the same flow as wifi_ap — choose STA or AP mode
Both failed and timeout fire on any connection failure — wire both or just failed

wifi_ap

WiFi AP

Creates a WiFi hotspot. Phones and laptops can connect directly — no router needed. Shows SSID and IP on OLED.

Ports

Name	Dir	Type	Description
trigger	← IN	trigger	Start the access point
ready	OUT →	ok	AP is up and accepting connections
ip	OUT →	string	Gateway IP (always 192.168.4.1)

Config

Key	Widget	Default	Description
ssid	text	BLUEHASH	Hotspot name visible to devices
password	text		Password — leave empty for open network
channel	number	1	WiFi channel 1–13

Notes

Gateway is always 192.168.4.1 — users open this in their browser
Open network (no password) is simplest for demos and local use
Always wire ready → web_server to start the HTTP server

Example

[start] → boot → [wifi_ap "BLUEHASH"] → ready → [web_server port=80]

web_server

Web server

Starts an HTTP server on port 80. Must be running for any browser requests to be served. Runs handleClient() every loop.

Ports

Name	Dir	Type	Description
trigger	← IN	trigger	Start the web server
started	OUT →	ok	Server is live and accepting connections

Config

Key	Widget	Default	Description
port	number	80	HTTP port (80 = no port needed in browser URL)

Notes

html_page, web_button, cam_web register their routes during setup() — before web_server starts. Routes are queued and applied automatically when the server starts.
Keep port 80 — any other port requires users to type 192.168.4.1:PORT
tick() runs every loop iteration automatically

Example

[wifi_ap] → ready → [web_server] → started → [show_text "Server live"]

html_page

HTML page

Serves a fully styled HTML page at "/". The page includes a dark theme, button styling, and JS helper functions. No wiring needed — presence in the flow is enough.

Config

Key	Widget	Default	Description
title	text	BLUEHASH	Browser tab title
body	textarea		HTML for the <body> tag. Use single quotes in onclick to avoid escaping.

Notes

No edges needed — the node registers GET "/" in setup() automatically
Use single quotes inside onclick attributes: onclick='bh_img("/snap")'
Built-in JS: bh_call(url) fetches a route and shows response in <div id="out">
Built-in JS: bh_img(url) fetches a route and shows result in <img id="preview">
Built-in JS: bh_poll(url, ms) auto-refreshes <img id="preview"> every ms milliseconds

Example

// Snap button + live preview
<button onclick='bh_img("/snap")'>📷 Capture</button>
<img id='preview'>

// Auto-refresh every 800ms (live view)
<script>bh_poll("/snap", 800)</script>
<img id='preview'>

// Button triggers flow + shows result text
<button onclick='bh_call("/btn/0")'>Read sensor</button>
<div id='out'></div>

web_button

Web button

Registers GET /btn/{id} on the web server. When a browser calls that URL, fires the pressed output on the next loop tick.

Ports

Name	Dir	Type	Description
pressed	OUT →	ok	Fires when browser calls GET /btn/{btnId}

Config

Key	Widget	Default	Description
label	text	Button	For reference only — not served automatically
btnId	text	0	URL segment — registers route /btn/{btnId}

Notes

No edges needed to register the route — just add the node
Wire pressed to any flow node: cam_capture, ir_send, led toggle, etc.
Browser response is always 200 "ok" — show result by calling bh_img("/snap") separately
Use unique btnId for each web_button in the same flow: 0, 1, 2…
Cannot be used with cam_web if you also want camera — cam_web registers /snap, wire web_button.pressed to ir_send, led, etc.

Example

// HTML: two buttons
<button onclick='bh_call("/btn/0")'>💡 LED ON</button>
<button onclick='bh_call("/btn/1")'>💡 LED OFF</button>
<div id='out'></div>

// Flow wiring:
[web_button id=0] → pressed → [digital_write pin=2 HIGH]
[web_button id=1] → pressed → [digital_write pin=2 LOW]

cam_web

Camera → web

Initializes the camera and serves JPEG snapshots at /snap. Each browser request captures a fresh frame.

Ports

Name	Dir	Type	Description
ready	OUT →	ok	Camera initialized and /snap is live
error	OUT →	error	Camera initialization failed

Config

Key	Widget	Default	Description
resolution	select	QVGA (320x240)	QQVGA (160×120) \| QVGA (320×240) \| VGA (640×480) \| SVGA (800×600)
quality	number	12	JPEG quality 4–63 (lower = smaller, faster)

Notes

No edges needed to register /snap — just add the node
Cannot be in the same flow as camera_capture — both call bh_cam_init() and will conflict
In html_page body: <img id="preview"> + bh_img("/snap") shows a snapshot on demand
For live view: bh_poll("/snap", 800) auto-refreshes every 800ms
QVGA is best for ESP32-CAM — fast capture, good quality, loads quickly on phone

Example

// Minimal camera web flow:
Nodes: start → wifi_ap → web_server
       html_page (body below)
       cam_web

// html_page body:
<h1>Camera</h1>
<button onclick='bh_img("/snap")'>📷 Snap</button>
<img id='preview'>

http_get

HTTP GET

Makes a blocking HTTP GET request to a URL and returns the response body.

Ports

Name	Dir	Type	Description
trigger	← IN	trigger	Make the request
success	OUT →	ok	Request completed with 2xx status
body	OUT →	string	Response body text
statuscode	OUT →	number	HTTP status code
error	OUT →	error	Connection failed or negative code

Config

Key	Widget	Default	Description
url	text	—	Full URL including https://
timeout	number	5000	Request timeout in ms

Notes

Requires wifi_connect first
Blocks the loop for the duration of the request

http_post

HTTP POST

Makes a blocking HTTP POST request with a body.

Ports

Name	Dir	Type	Description
trigger	← IN	trigger	Send the request
body	← IN	string	Request body — triggers send automatically when wired
success	OUT →	ok	Request succeeded
response	OUT →	string	Response body text
error	OUT →	error	Request failed

Config

Key	Widget	Default	Description
url	text	—	Endpoint URL
contentType	select	application/json	Content-Type header
timeout	number	5000	Timeout in ms

mqtt_publish

MQTT publish

Publishes a message to an MQTT broker topic.

Ports

Name	Dir	Type	Description
trigger	← IN	trigger	Publish the message
payload	← IN	string	Message payload — triggers publish when wired
sent	OUT →	ok	Message published
failed	OUT →	error	Broker unreachable or publish failed

Config

Key	Widget	Default	Description
broker	text	—	Broker IP or hostname
port	number	1883	MQTT port
topic	text	—	Topic to publish to e.g. bluehash/sensor
retain	toggle	false	Retain message on broker

Data / Logic

Variables, math, storage, scaling

set_variable

Set variable

Stores a string value in memory and passes it downstream.

Ports

Name	Dir	Type	Description
trigger	← IN	trigger	Output the stored value
value	← IN	string	New value to store — triggers output automatically
done	OUT →	trigger	Fires after outputting
value	OUT →	string	Current stored value

Config

Key	Widget	Default	Description
value	text	—	Initial/default value

math

Math

Applies an arithmetic operator to two float values (A op B).

Ports

Name	Dir	Type	Description
run	← IN	trigger	Calculate and output result
a	← IN	number	Left operand
b	← IN	number	Right operand
result	OUT →	number	Calculation result
divbyzero	OUT →	error	Fires on division by zero

Config

Key	Widget	Default	Description
operator	select	—	+ − × ÷ % ** abs min max round floor ceil

map_scale

Map / scale

Linearly maps a value from one range to another and clamps the output.

Ports

Name	Dir	Type	Description
trigger	← IN	trigger	Map the current value
value	← IN	number	Value to map — triggers automatically when wired
mapped	OUT →	number	Mapped output value

Config

Key	Widget	Default	Description
inMin	number	0	Input range minimum
inMax	number	4095	Input range maximum
outMin	number	0	Output range minimum
outMax	number	100	Output range maximum

Example

// ADC → percentage
[analog_read] → raw → [map_scale 0–4095 → 0–100] → mapped → [progress_bar]

nvs_store

NVS store

Saves a string value to non-volatile flash storage. Survives reboots and deep sleep.

Ports

Name	Dir	Type	Description
trigger	← IN	trigger	Save the value
value	← IN	string	Value to save — triggers save automatically
saved	OUT →	ok	Value saved

Config

Key	Widget	Default	Description
namespace	text	bluehash	NVS namespace (max 15 chars)
key	text	—	Key name (max 15 chars)

Notes

NVS has limited write cycles (~100,000) — do not write on every timer tick

nvs_read

NVS read

Reads a value from non-volatile flash storage.

Ports

Name	Dir	Type	Description
trigger	← IN	trigger	Read the value
value	OUT →	string	Retrieved value or default
found	OUT →	ok	Key existed in storage
useddefault	OUT →	neutral	Key not found — default returned

Config

Key	Widget	Default	Description
namespace	text	bluehash	NVS namespace
key	text	—	Key name
default	text	—	Value to return if key not found

System

Sleep, restart, logging, custom code

deep_sleep

Deep sleep

Puts the ESP32 into deep sleep, consuming ~10µA. Wakes on timer or external pin.

Ports

Name	Dir	Type	Description
trigger	← IN	trigger	Enter deep sleep

Config

Key	Widget	Default	Description
duration	number	0	Wake-up time in ms (0 = no timer wake, use external pin)

Notes

RAM contents are lost — save state to NVS before sleeping
Wakes via start node — connect start → wake for post-sleep logic

restart

Restart

Reboots the ESP32 after an optional delay.

Ports

Name	Dir	Type	Description
trigger	← IN	trigger	Restart the device

Config

Key	Widget	Default	Description
delay	number	500	Delay before restart in ms

beep

Beep

Plays a tone on the buzzer pin.

Ports

Name	Dir	Type	Description
trigger	← IN	trigger	Play the tone
done	OUT →	trigger	Fires after tone completes

Config

Key	Widget	Default	Description
pin	pin	—	Buzzer pin
freq	number	1000	Tone frequency in Hz
duration	number	200	Tone duration in ms

log

Log

Prints a message to Serial monitor at the configured log level.

Ports

Name	Dir	Type	Description
trigger	← IN	trigger	Print the message
done	OUT →	trigger	Fires after printing

Config

Key	Widget	Default	Description
message	text	—	Message to print
level	select	INFO	INFO \| WARN \| ERROR \| DEBUG

custom_code

Custom code

Runs arbitrary C++ code inside the generated flow. Full access to bh_hal.h API.

Ports

Name	Dir	Type	Description
trigger	← IN	trigger	Execute the code
done	OUT →	trigger	Fires after execution
returnval	OUT →	number	Float return value (call node_xxx_output_returnval(v))
error	OUT →	error	Error path (call node_xxx_output_error())

Config

Key	Widget	Default	Description
code	code	—	C++ code to run. Use bh_* functions from the HAL.

Notes

Code runs inside a void function — use return to exit early
bh_hal.h is already included — call bh_display_print(), bh_led(), etc. directly

Example

// Flash LED 3 times
bh_led_blink(3, 100, 100);
bh_display_print_center(20, "Done!");
bh_display_show();

program

Program

Launches a community program from the library. The program runs until it calls bh_program_exit().

Ports

Name	Dir	Type	Description
trigger	← IN	trigger	Launch the program
done	OUT →	trigger	Fires when program exits cleanly
returnval	OUT →	number	Value returned by the program
error	OUT →	error	Program not found or crashed

Config

Key	Widget	Default	Description
programId	text	—	Library program ID (from the community library)

Notes

Programs are embedded at compile time — the program ID must exist in the compiler's library
Long-pressing BACK during a program triggers bh_exit_requested() which programs must handle

Web panel recipes

Common patterns combining wifi_ap + web_server + html_page + cam_web + web_button.

Camera snap on button click

wifi_apweb_serverhtml_pagecam_web

Phone connects, taps a button, sees a fresh JPEG.

// Edges: start→wifi_ap, wifi_ap.ready→web_server
// html_page body:
<h1>Camera</h1>
<button onclick='bh_img("/snap")'>📷 Snap</button>
<img id='preview'>

Live view (auto-refresh)

wifi_apweb_serverhtml_pagecam_web

Image refreshes automatically every 800ms — no button needed.

// html_page body:
<h1>Live View</h1>
<img id='preview'>
<script>bh_poll("/snap", 800)</script>

Remote control panel

wifi_apweb_serverhtml_pageweb_button ×2

Two buttons control the LED via browser. No camera.

// web_button id=0 → pressed → digital_write HIGH
// web_button id=1 → pressed → digital_write LOW
// html_page body:
<h1>LED Control</h1>
<button onclick='bh_call("/btn/0")'>💡 ON</button>
<button onclick='bh_call("/btn/1")'>💡 OFF</button>
<div id='out'></div>

Sensor dashboard

wifi_apweb_serverhtml_pageweb_buttonanalog_read

Click to read a sensor and see the value in the browser.

// web_button id=0 → pressed → analog_read → (result shown via separate GET)
// html_page body:
<h1>Sensors</h1>
<button onclick='bh_call("/btn/0")'>📊 Read ADC</button>
<div id='out'>Press to read</div>

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